| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Copyright (C) 1999 Eric Youngdale |
| * Copyright (C) 2014 Christoph Hellwig |
| * |
| * SCSI queueing library. |
| * Initial versions: Eric Youngdale (eric@andante.org). |
| * Based upon conversations with large numbers |
| * of people at Linux Expo. |
| */ |
| |
| #include <linux/bio.h> |
| #include <linux/bitops.h> |
| #include <linux/blkdev.h> |
| #include <linux/completion.h> |
| #include <linux/kernel.h> |
| #include <linux/export.h> |
| #include <linux/init.h> |
| #include <linux/pci.h> |
| #include <linux/delay.h> |
| #include <linux/hardirq.h> |
| #include <linux/scatterlist.h> |
| #include <linux/blk-mq.h> |
| #include <linux/blk-integrity.h> |
| #include <linux/ratelimit.h> |
| #include <asm/unaligned.h> |
| |
| #include <scsi/scsi.h> |
| #include <scsi/scsi_cmnd.h> |
| #include <scsi/scsi_dbg.h> |
| #include <scsi/scsi_device.h> |
| #include <scsi/scsi_driver.h> |
| #include <scsi/scsi_eh.h> |
| #include <scsi/scsi_host.h> |
| #include <scsi/scsi_transport.h> /* __scsi_init_queue() */ |
| #include <scsi/scsi_dh.h> |
| |
| #include <trace/events/scsi.h> |
| |
| #include "scsi_debugfs.h" |
| #include "scsi_priv.h" |
| #include "scsi_logging.h" |
| |
| /* |
| * Size of integrity metadata is usually small, 1 inline sg should |
| * cover normal cases. |
| */ |
| #ifdef CONFIG_ARCH_NO_SG_CHAIN |
| #define SCSI_INLINE_PROT_SG_CNT 0 |
| #define SCSI_INLINE_SG_CNT 0 |
| #else |
| #define SCSI_INLINE_PROT_SG_CNT 1 |
| #define SCSI_INLINE_SG_CNT 2 |
| #endif |
| |
| static struct kmem_cache *scsi_sense_cache; |
| static DEFINE_MUTEX(scsi_sense_cache_mutex); |
| |
| static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd); |
| |
| int scsi_init_sense_cache(struct Scsi_Host *shost) |
| { |
| int ret = 0; |
| |
| mutex_lock(&scsi_sense_cache_mutex); |
| if (!scsi_sense_cache) { |
| scsi_sense_cache = |
| kmem_cache_create_usercopy("scsi_sense_cache", |
| SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN, |
| 0, SCSI_SENSE_BUFFERSIZE, NULL); |
| if (!scsi_sense_cache) |
| ret = -ENOMEM; |
| } |
| mutex_unlock(&scsi_sense_cache_mutex); |
| return ret; |
| } |
| |
| /* |
| * When to reinvoke queueing after a resource shortage. It's 3 msecs to |
| * not change behaviour from the previous unplug mechanism, experimentation |
| * may prove this needs changing. |
| */ |
| #define SCSI_QUEUE_DELAY 3 |
| |
| static void |
| scsi_set_blocked(struct scsi_cmnd *cmd, int reason) |
| { |
| struct Scsi_Host *host = cmd->device->host; |
| struct scsi_device *device = cmd->device; |
| struct scsi_target *starget = scsi_target(device); |
| |
| /* |
| * Set the appropriate busy bit for the device/host. |
| * |
| * If the host/device isn't busy, assume that something actually |
| * completed, and that we should be able to queue a command now. |
| * |
| * Note that the prior mid-layer assumption that any host could |
| * always queue at least one command is now broken. The mid-layer |
| * will implement a user specifiable stall (see |
| * scsi_host.max_host_blocked and scsi_device.max_device_blocked) |
| * if a command is requeued with no other commands outstanding |
| * either for the device or for the host. |
| */ |
| switch (reason) { |
| case SCSI_MLQUEUE_HOST_BUSY: |
| atomic_set(&host->host_blocked, host->max_host_blocked); |
| break; |
| case SCSI_MLQUEUE_DEVICE_BUSY: |
| case SCSI_MLQUEUE_EH_RETRY: |
| atomic_set(&device->device_blocked, |
| device->max_device_blocked); |
| break; |
| case SCSI_MLQUEUE_TARGET_BUSY: |
| atomic_set(&starget->target_blocked, |
| starget->max_target_blocked); |
| break; |
| } |
| } |
| |
| static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd) |
| { |
| struct request *rq = scsi_cmd_to_rq(cmd); |
| |
| if (rq->rq_flags & RQF_DONTPREP) { |
| rq->rq_flags &= ~RQF_DONTPREP; |
| scsi_mq_uninit_cmd(cmd); |
| } else { |
| WARN_ON_ONCE(true); |
| } |
| blk_mq_requeue_request(rq, true); |
| } |
| |
| /** |
| * __scsi_queue_insert - private queue insertion |
| * @cmd: The SCSI command being requeued |
| * @reason: The reason for the requeue |
| * @unbusy: Whether the queue should be unbusied |
| * |
| * This is a private queue insertion. The public interface |
| * scsi_queue_insert() always assumes the queue should be unbusied |
| * because it's always called before the completion. This function is |
| * for a requeue after completion, which should only occur in this |
| * file. |
| */ |
| static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy) |
| { |
| struct scsi_device *device = cmd->device; |
| |
| SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd, |
| "Inserting command %p into mlqueue\n", cmd)); |
| |
| scsi_set_blocked(cmd, reason); |
| |
| /* |
| * Decrement the counters, since these commands are no longer |
| * active on the host/device. |
| */ |
| if (unbusy) |
| scsi_device_unbusy(device, cmd); |
| |
| /* |
| * Requeue this command. It will go before all other commands |
| * that are already in the queue. Schedule requeue work under |
| * lock such that the kblockd_schedule_work() call happens |
| * before blk_cleanup_queue() finishes. |
| */ |
| cmd->result = 0; |
| |
| blk_mq_requeue_request(scsi_cmd_to_rq(cmd), true); |
| } |
| |
| /** |
| * scsi_queue_insert - Reinsert a command in the queue. |
| * @cmd: command that we are adding to queue. |
| * @reason: why we are inserting command to queue. |
| * |
| * We do this for one of two cases. Either the host is busy and it cannot accept |
| * any more commands for the time being, or the device returned QUEUE_FULL and |
| * can accept no more commands. |
| * |
| * Context: This could be called either from an interrupt context or a normal |
| * process context. |
| */ |
| void scsi_queue_insert(struct scsi_cmnd *cmd, int reason) |
| { |
| __scsi_queue_insert(cmd, reason, true); |
| } |
| |
| |
| /** |
| * __scsi_execute - insert request and wait for the result |
| * @sdev: scsi device |
| * @cmd: scsi command |
| * @data_direction: data direction |
| * @buffer: data buffer |
| * @bufflen: len of buffer |
| * @sense: optional sense buffer |
| * @sshdr: optional decoded sense header |
| * @timeout: request timeout in HZ |
| * @retries: number of times to retry request |
| * @flags: flags for ->cmd_flags |
| * @rq_flags: flags for ->rq_flags |
| * @resid: optional residual length |
| * |
| * Returns the scsi_cmnd result field if a command was executed, or a negative |
| * Linux error code if we didn't get that far. |
| */ |
| int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, |
| int data_direction, void *buffer, unsigned bufflen, |
| unsigned char *sense, struct scsi_sense_hdr *sshdr, |
| int timeout, int retries, u64 flags, req_flags_t rq_flags, |
| int *resid) |
| { |
| struct request *req; |
| struct scsi_request *rq; |
| int ret; |
| |
| req = scsi_alloc_request(sdev->request_queue, |
| data_direction == DMA_TO_DEVICE ? |
| REQ_OP_DRV_OUT : REQ_OP_DRV_IN, |
| rq_flags & RQF_PM ? BLK_MQ_REQ_PM : 0); |
| if (IS_ERR(req)) |
| return PTR_ERR(req); |
| |
| rq = scsi_req(req); |
| |
| if (bufflen) { |
| ret = blk_rq_map_kern(sdev->request_queue, req, |
| buffer, bufflen, GFP_NOIO); |
| if (ret) |
| goto out; |
| } |
| rq->cmd_len = COMMAND_SIZE(cmd[0]); |
| memcpy(rq->cmd, cmd, rq->cmd_len); |
| rq->retries = retries; |
| req->timeout = timeout; |
| req->cmd_flags |= flags; |
| req->rq_flags |= rq_flags | RQF_QUIET; |
| |
| /* |
| * head injection *required* here otherwise quiesce won't work |
| */ |
| blk_execute_rq(NULL, req, 1); |
| |
| /* |
| * Some devices (USB mass-storage in particular) may transfer |
| * garbage data together with a residue indicating that the data |
| * is invalid. Prevent the garbage from being misinterpreted |
| * and prevent security leaks by zeroing out the excess data. |
| */ |
| if (unlikely(rq->resid_len > 0 && rq->resid_len <= bufflen)) |
| memset(buffer + (bufflen - rq->resid_len), 0, rq->resid_len); |
| |
| if (resid) |
| *resid = rq->resid_len; |
| if (sense && rq->sense_len) |
| memcpy(sense, rq->sense, SCSI_SENSE_BUFFERSIZE); |
| if (sshdr) |
| scsi_normalize_sense(rq->sense, rq->sense_len, sshdr); |
| ret = rq->result; |
| out: |
| blk_mq_free_request(req); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(__scsi_execute); |
| |
| /* |
| * Wake up the error handler if necessary. Avoid as follows that the error |
| * handler is not woken up if host in-flight requests number == |
| * shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination |
| * with an RCU read lock in this function to ensure that this function in |
| * its entirety either finishes before scsi_eh_scmd_add() increases the |
| * host_failed counter or that it notices the shost state change made by |
| * scsi_eh_scmd_add(). |
| */ |
| static void scsi_dec_host_busy(struct Scsi_Host *shost, struct scsi_cmnd *cmd) |
| { |
| unsigned long flags; |
| |
| rcu_read_lock(); |
| __clear_bit(SCMD_STATE_INFLIGHT, &cmd->state); |
| if (unlikely(scsi_host_in_recovery(shost))) { |
| spin_lock_irqsave(shost->host_lock, flags); |
| if (shost->host_failed || shost->host_eh_scheduled) |
| scsi_eh_wakeup(shost); |
| spin_unlock_irqrestore(shost->host_lock, flags); |
| } |
| rcu_read_unlock(); |
| } |
| |
| void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd) |
| { |
| struct Scsi_Host *shost = sdev->host; |
| struct scsi_target *starget = scsi_target(sdev); |
| |
| scsi_dec_host_busy(shost, cmd); |
| |
| if (starget->can_queue > 0) |
| atomic_dec(&starget->target_busy); |
| |
| sbitmap_put(&sdev->budget_map, cmd->budget_token); |
| cmd->budget_token = -1; |
| } |
| |
| static void scsi_kick_queue(struct request_queue *q) |
| { |
| blk_mq_run_hw_queues(q, false); |
| } |
| |
| /* |
| * Called for single_lun devices on IO completion. Clear starget_sdev_user, |
| * and call blk_run_queue for all the scsi_devices on the target - |
| * including current_sdev first. |
| * |
| * Called with *no* scsi locks held. |
| */ |
| static void scsi_single_lun_run(struct scsi_device *current_sdev) |
| { |
| struct Scsi_Host *shost = current_sdev->host; |
| struct scsi_device *sdev, *tmp; |
| struct scsi_target *starget = scsi_target(current_sdev); |
| unsigned long flags; |
| |
| spin_lock_irqsave(shost->host_lock, flags); |
| starget->starget_sdev_user = NULL; |
| spin_unlock_irqrestore(shost->host_lock, flags); |
| |
| /* |
| * Call blk_run_queue for all LUNs on the target, starting with |
| * current_sdev. We race with others (to set starget_sdev_user), |
| * but in most cases, we will be first. Ideally, each LU on the |
| * target would get some limited time or requests on the target. |
| */ |
| scsi_kick_queue(current_sdev->request_queue); |
| |
| spin_lock_irqsave(shost->host_lock, flags); |
| if (starget->starget_sdev_user) |
| goto out; |
| list_for_each_entry_safe(sdev, tmp, &starget->devices, |
| same_target_siblings) { |
| if (sdev == current_sdev) |
| continue; |
| if (scsi_device_get(sdev)) |
| continue; |
| |
| spin_unlock_irqrestore(shost->host_lock, flags); |
| scsi_kick_queue(sdev->request_queue); |
| spin_lock_irqsave(shost->host_lock, flags); |
| |
| scsi_device_put(sdev); |
| } |
| out: |
| spin_unlock_irqrestore(shost->host_lock, flags); |
| } |
| |
| static inline bool scsi_device_is_busy(struct scsi_device *sdev) |
| { |
| if (scsi_device_busy(sdev) >= sdev->queue_depth) |
| return true; |
| if (atomic_read(&sdev->device_blocked) > 0) |
| return true; |
| return false; |
| } |
| |
| static inline bool scsi_target_is_busy(struct scsi_target *starget) |
| { |
| if (starget->can_queue > 0) { |
| if (atomic_read(&starget->target_busy) >= starget->can_queue) |
| return true; |
| if (atomic_read(&starget->target_blocked) > 0) |
| return true; |
| } |
| return false; |
| } |
| |
| static inline bool scsi_host_is_busy(struct Scsi_Host *shost) |
| { |
| if (atomic_read(&shost->host_blocked) > 0) |
| return true; |
| if (shost->host_self_blocked) |
| return true; |
| return false; |
| } |
| |
| static void scsi_starved_list_run(struct Scsi_Host *shost) |
| { |
| LIST_HEAD(starved_list); |
| struct scsi_device *sdev; |
| unsigned long flags; |
| |
| spin_lock_irqsave(shost->host_lock, flags); |
| list_splice_init(&shost->starved_list, &starved_list); |
| |
| while (!list_empty(&starved_list)) { |
| struct request_queue *slq; |
| |
| /* |
| * As long as shost is accepting commands and we have |
| * starved queues, call blk_run_queue. scsi_request_fn |
| * drops the queue_lock and can add us back to the |
| * starved_list. |
| * |
| * host_lock protects the starved_list and starved_entry. |
| * scsi_request_fn must get the host_lock before checking |
| * or modifying starved_list or starved_entry. |
| */ |
| if (scsi_host_is_busy(shost)) |
| break; |
| |
| sdev = list_entry(starved_list.next, |
| struct scsi_device, starved_entry); |
| list_del_init(&sdev->starved_entry); |
| if (scsi_target_is_busy(scsi_target(sdev))) { |
| list_move_tail(&sdev->starved_entry, |
| &shost->starved_list); |
| continue; |
| } |
| |
| /* |
| * Once we drop the host lock, a racing scsi_remove_device() |
| * call may remove the sdev from the starved list and destroy |
| * it and the queue. Mitigate by taking a reference to the |
| * queue and never touching the sdev again after we drop the |
| * host lock. Note: if __scsi_remove_device() invokes |
| * blk_cleanup_queue() before the queue is run from this |
| * function then blk_run_queue() will return immediately since |
| * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING. |
| */ |
| slq = sdev->request_queue; |
| if (!blk_get_queue(slq)) |
| continue; |
| spin_unlock_irqrestore(shost->host_lock, flags); |
| |
| scsi_kick_queue(slq); |
| blk_put_queue(slq); |
| |
| spin_lock_irqsave(shost->host_lock, flags); |
| } |
| /* put any unprocessed entries back */ |
| list_splice(&starved_list, &shost->starved_list); |
| spin_unlock_irqrestore(shost->host_lock, flags); |
| } |
| |
| /** |
| * scsi_run_queue - Select a proper request queue to serve next. |
| * @q: last request's queue |
| * |
| * The previous command was completely finished, start a new one if possible. |
| */ |
| static void scsi_run_queue(struct request_queue *q) |
| { |
| struct scsi_device *sdev = q->queuedata; |
| |
| if (scsi_target(sdev)->single_lun) |
| scsi_single_lun_run(sdev); |
| if (!list_empty(&sdev->host->starved_list)) |
| scsi_starved_list_run(sdev->host); |
| |
| blk_mq_run_hw_queues(q, false); |
| } |
| |
| void scsi_requeue_run_queue(struct work_struct *work) |
| { |
| struct scsi_device *sdev; |
| struct request_queue *q; |
| |
| sdev = container_of(work, struct scsi_device, requeue_work); |
| q = sdev->request_queue; |
| scsi_run_queue(q); |
| } |
| |
| void scsi_run_host_queues(struct Scsi_Host *shost) |
| { |
| struct scsi_device *sdev; |
| |
| shost_for_each_device(sdev, shost) |
| scsi_run_queue(sdev->request_queue); |
| } |
| |
| static void scsi_uninit_cmd(struct scsi_cmnd *cmd) |
| { |
| if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) { |
| struct scsi_driver *drv = scsi_cmd_to_driver(cmd); |
| |
| if (drv->uninit_command) |
| drv->uninit_command(cmd); |
| } |
| } |
| |
| void scsi_free_sgtables(struct scsi_cmnd *cmd) |
| { |
| if (cmd->sdb.table.nents) |
| sg_free_table_chained(&cmd->sdb.table, |
| SCSI_INLINE_SG_CNT); |
| if (scsi_prot_sg_count(cmd)) |
| sg_free_table_chained(&cmd->prot_sdb->table, |
| SCSI_INLINE_PROT_SG_CNT); |
| } |
| EXPORT_SYMBOL_GPL(scsi_free_sgtables); |
| |
| static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd) |
| { |
| scsi_free_sgtables(cmd); |
| scsi_uninit_cmd(cmd); |
| } |
| |
| static void scsi_run_queue_async(struct scsi_device *sdev) |
| { |
| if (scsi_target(sdev)->single_lun || |
| !list_empty(&sdev->host->starved_list)) { |
| kblockd_schedule_work(&sdev->requeue_work); |
| } else { |
| /* |
| * smp_mb() present in sbitmap_queue_clear() or implied in |
| * .end_io is for ordering writing .device_busy in |
| * scsi_device_unbusy() and reading sdev->restarts. |
| */ |
| int old = atomic_read(&sdev->restarts); |
| |
| /* |
| * ->restarts has to be kept as non-zero if new budget |
| * contention occurs. |
| * |
| * No need to run queue when either another re-run |
| * queue wins in updating ->restarts or a new budget |
| * contention occurs. |
| */ |
| if (old && atomic_cmpxchg(&sdev->restarts, old, 0) == old) |
| blk_mq_run_hw_queues(sdev->request_queue, true); |
| } |
| } |
| |
| /* Returns false when no more bytes to process, true if there are more */ |
| static bool scsi_end_request(struct request *req, blk_status_t error, |
| unsigned int bytes) |
| { |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); |
| struct scsi_device *sdev = cmd->device; |
| struct request_queue *q = sdev->request_queue; |
| |
| if (blk_update_request(req, error, bytes)) |
| return true; |
| |
| if (blk_queue_add_random(q)) |
| add_disk_randomness(req->rq_disk); |
| |
| if (!blk_rq_is_passthrough(req)) { |
| WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED)); |
| cmd->flags &= ~SCMD_INITIALIZED; |
| } |
| |
| /* |
| * Calling rcu_barrier() is not necessary here because the |
| * SCSI error handler guarantees that the function called by |
| * call_rcu() has been called before scsi_end_request() is |
| * called. |
| */ |
| destroy_rcu_head(&cmd->rcu); |
| |
| /* |
| * In the MQ case the command gets freed by __blk_mq_end_request, |
| * so we have to do all cleanup that depends on it earlier. |
| * |
| * We also can't kick the queues from irq context, so we |
| * will have to defer it to a workqueue. |
| */ |
| scsi_mq_uninit_cmd(cmd); |
| |
| /* |
| * queue is still alive, so grab the ref for preventing it |
| * from being cleaned up during running queue. |
| */ |
| percpu_ref_get(&q->q_usage_counter); |
| |
| __blk_mq_end_request(req, error); |
| |
| scsi_run_queue_async(sdev); |
| |
| percpu_ref_put(&q->q_usage_counter); |
| return false; |
| } |
| |
| /** |
| * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t |
| * @cmd: SCSI command |
| * @result: scsi error code |
| * |
| * Translate a SCSI result code into a blk_status_t value. May reset the host |
| * byte of @cmd->result. |
| */ |
| static blk_status_t scsi_result_to_blk_status(struct scsi_cmnd *cmd, int result) |
| { |
| switch (host_byte(result)) { |
| case DID_OK: |
| if (scsi_status_is_good(result)) |
| return BLK_STS_OK; |
| return BLK_STS_IOERR; |
| case DID_TRANSPORT_FAILFAST: |
| case DID_TRANSPORT_MARGINAL: |
| return BLK_STS_TRANSPORT; |
| case DID_TARGET_FAILURE: |
| set_host_byte(cmd, DID_OK); |
| return BLK_STS_TARGET; |
| case DID_NEXUS_FAILURE: |
| set_host_byte(cmd, DID_OK); |
| return BLK_STS_NEXUS; |
| case DID_ALLOC_FAILURE: |
| set_host_byte(cmd, DID_OK); |
| return BLK_STS_NOSPC; |
| case DID_MEDIUM_ERROR: |
| set_host_byte(cmd, DID_OK); |
| return BLK_STS_MEDIUM; |
| default: |
| return BLK_STS_IOERR; |
| } |
| } |
| |
| /* Helper for scsi_io_completion() when "reprep" action required. */ |
| static void scsi_io_completion_reprep(struct scsi_cmnd *cmd, |
| struct request_queue *q) |
| { |
| /* A new command will be prepared and issued. */ |
| scsi_mq_requeue_cmd(cmd); |
| } |
| |
| static bool scsi_cmd_runtime_exceeced(struct scsi_cmnd *cmd) |
| { |
| struct request *req = scsi_cmd_to_rq(cmd); |
| unsigned long wait_for; |
| |
| if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT) |
| return false; |
| |
| wait_for = (cmd->allowed + 1) * req->timeout; |
| if (time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { |
| scmd_printk(KERN_ERR, cmd, "timing out command, waited %lus\n", |
| wait_for/HZ); |
| return true; |
| } |
| return false; |
| } |
| |
| /* Helper for scsi_io_completion() when special action required. */ |
| static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result) |
| { |
| struct request_queue *q = cmd->device->request_queue; |
| struct request *req = scsi_cmd_to_rq(cmd); |
| int level = 0; |
| enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY, |
| ACTION_DELAYED_RETRY} action; |
| struct scsi_sense_hdr sshdr; |
| bool sense_valid; |
| bool sense_current = true; /* false implies "deferred sense" */ |
| blk_status_t blk_stat; |
| |
| sense_valid = scsi_command_normalize_sense(cmd, &sshdr); |
| if (sense_valid) |
| sense_current = !scsi_sense_is_deferred(&sshdr); |
| |
| blk_stat = scsi_result_to_blk_status(cmd, result); |
| |
| if (host_byte(result) == DID_RESET) { |
| /* Third party bus reset or reset for error recovery |
| * reasons. Just retry the command and see what |
| * happens. |
| */ |
| action = ACTION_RETRY; |
| } else if (sense_valid && sense_current) { |
| switch (sshdr.sense_key) { |
| case UNIT_ATTENTION: |
| if (cmd->device->removable) { |
| /* Detected disc change. Set a bit |
| * and quietly refuse further access. |
| */ |
| cmd->device->changed = 1; |
| action = ACTION_FAIL; |
| } else { |
| /* Must have been a power glitch, or a |
| * bus reset. Could not have been a |
| * media change, so we just retry the |
| * command and see what happens. |
| */ |
| action = ACTION_RETRY; |
| } |
| break; |
| case ILLEGAL_REQUEST: |
| /* If we had an ILLEGAL REQUEST returned, then |
| * we may have performed an unsupported |
| * command. The only thing this should be |
| * would be a ten byte read where only a six |
| * byte read was supported. Also, on a system |
| * where READ CAPACITY failed, we may have |
| * read past the end of the disk. |
| */ |
| if ((cmd->device->use_10_for_rw && |
| sshdr.asc == 0x20 && sshdr.ascq == 0x00) && |
| (cmd->cmnd[0] == READ_10 || |
| cmd->cmnd[0] == WRITE_10)) { |
| /* This will issue a new 6-byte command. */ |
| cmd->device->use_10_for_rw = 0; |
| action = ACTION_REPREP; |
| } else if (sshdr.asc == 0x10) /* DIX */ { |
| action = ACTION_FAIL; |
| blk_stat = BLK_STS_PROTECTION; |
| /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */ |
| } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) { |
| action = ACTION_FAIL; |
| blk_stat = BLK_STS_TARGET; |
| } else |
| action = ACTION_FAIL; |
| break; |
| case ABORTED_COMMAND: |
| action = ACTION_FAIL; |
| if (sshdr.asc == 0x10) /* DIF */ |
| blk_stat = BLK_STS_PROTECTION; |
| break; |
| case NOT_READY: |
| /* If the device is in the process of becoming |
| * ready, or has a temporary blockage, retry. |
| */ |
| if (sshdr.asc == 0x04) { |
| switch (sshdr.ascq) { |
| case 0x01: /* becoming ready */ |
| case 0x04: /* format in progress */ |
| case 0x05: /* rebuild in progress */ |
| case 0x06: /* recalculation in progress */ |
| case 0x07: /* operation in progress */ |
| case 0x08: /* Long write in progress */ |
| case 0x09: /* self test in progress */ |
| case 0x11: /* notify (enable spinup) required */ |
| case 0x14: /* space allocation in progress */ |
| case 0x1a: /* start stop unit in progress */ |
| case 0x1b: /* sanitize in progress */ |
| case 0x1d: /* configuration in progress */ |
| case 0x24: /* depopulation in progress */ |
| action = ACTION_DELAYED_RETRY; |
| break; |
| case 0x0a: /* ALUA state transition */ |
| blk_stat = BLK_STS_AGAIN; |
| fallthrough; |
| default: |
| action = ACTION_FAIL; |
| break; |
| } |
| } else |
| action = ACTION_FAIL; |
| break; |
| case VOLUME_OVERFLOW: |
| /* See SSC3rXX or current. */ |
| action = ACTION_FAIL; |
| break; |
| case DATA_PROTECT: |
| action = ACTION_FAIL; |
| if ((sshdr.asc == 0x0C && sshdr.ascq == 0x12) || |
| (sshdr.asc == 0x55 && |
| (sshdr.ascq == 0x0E || sshdr.ascq == 0x0F))) { |
| /* Insufficient zone resources */ |
| blk_stat = BLK_STS_ZONE_OPEN_RESOURCE; |
| } |
| break; |
| default: |
| action = ACTION_FAIL; |
| break; |
| } |
| } else |
| action = ACTION_FAIL; |
| |
| if (action != ACTION_FAIL && scsi_cmd_runtime_exceeced(cmd)) |
| action = ACTION_FAIL; |
| |
| switch (action) { |
| case ACTION_FAIL: |
| /* Give up and fail the remainder of the request */ |
| if (!(req->rq_flags & RQF_QUIET)) { |
| static DEFINE_RATELIMIT_STATE(_rs, |
| DEFAULT_RATELIMIT_INTERVAL, |
| DEFAULT_RATELIMIT_BURST); |
| |
| if (unlikely(scsi_logging_level)) |
| level = |
| SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT, |
| SCSI_LOG_MLCOMPLETE_BITS); |
| |
| /* |
| * if logging is enabled the failure will be printed |
| * in scsi_log_completion(), so avoid duplicate messages |
| */ |
| if (!level && __ratelimit(&_rs)) { |
| scsi_print_result(cmd, NULL, FAILED); |
| if (sense_valid) |
| scsi_print_sense(cmd); |
| scsi_print_command(cmd); |
| } |
| } |
| if (!scsi_end_request(req, blk_stat, blk_rq_err_bytes(req))) |
| return; |
| fallthrough; |
| case ACTION_REPREP: |
| scsi_io_completion_reprep(cmd, q); |
| break; |
| case ACTION_RETRY: |
| /* Retry the same command immediately */ |
| __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false); |
| break; |
| case ACTION_DELAYED_RETRY: |
| /* Retry the same command after a delay */ |
| __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false); |
| break; |
| } |
| } |
| |
| /* |
| * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a |
| * new result that may suppress further error checking. Also modifies |
| * *blk_statp in some cases. |
| */ |
| static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result, |
| blk_status_t *blk_statp) |
| { |
| bool sense_valid; |
| bool sense_current = true; /* false implies "deferred sense" */ |
| struct request *req = scsi_cmd_to_rq(cmd); |
| struct scsi_sense_hdr sshdr; |
| |
| sense_valid = scsi_command_normalize_sense(cmd, &sshdr); |
| if (sense_valid) |
| sense_current = !scsi_sense_is_deferred(&sshdr); |
| |
| if (blk_rq_is_passthrough(req)) { |
| if (sense_valid) { |
| /* |
| * SG_IO wants current and deferred errors |
| */ |
| scsi_req(req)->sense_len = |
| min(8 + cmd->sense_buffer[7], |
| SCSI_SENSE_BUFFERSIZE); |
| } |
| if (sense_current) |
| *blk_statp = scsi_result_to_blk_status(cmd, result); |
| } else if (blk_rq_bytes(req) == 0 && sense_current) { |
| /* |
| * Flush commands do not transfers any data, and thus cannot use |
| * good_bytes != blk_rq_bytes(req) as the signal for an error. |
| * This sets *blk_statp explicitly for the problem case. |
| */ |
| *blk_statp = scsi_result_to_blk_status(cmd, result); |
| } |
| /* |
| * Recovered errors need reporting, but they're always treated as |
| * success, so fiddle the result code here. For passthrough requests |
| * we already took a copy of the original into sreq->result which |
| * is what gets returned to the user |
| */ |
| if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) { |
| bool do_print = true; |
| /* |
| * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d] |
| * skip print since caller wants ATA registers. Only occurs |
| * on SCSI ATA PASS_THROUGH commands when CK_COND=1 |
| */ |
| if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d)) |
| do_print = false; |
| else if (req->rq_flags & RQF_QUIET) |
| do_print = false; |
| if (do_print) |
| scsi_print_sense(cmd); |
| result = 0; |
| /* for passthrough, *blk_statp may be set */ |
| *blk_statp = BLK_STS_OK; |
| } |
| /* |
| * Another corner case: the SCSI status byte is non-zero but 'good'. |
| * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when |
| * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD |
| * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related |
| * intermediate statuses (both obsolete in SAM-4) as good. |
| */ |
| if ((result & 0xff) && scsi_status_is_good(result)) { |
| result = 0; |
| *blk_statp = BLK_STS_OK; |
| } |
| return result; |
| } |
| |
| /** |
| * scsi_io_completion - Completion processing for SCSI commands. |
| * @cmd: command that is finished. |
| * @good_bytes: number of processed bytes. |
| * |
| * We will finish off the specified number of sectors. If we are done, the |
| * command block will be released and the queue function will be goosed. If we |
| * are not done then we have to figure out what to do next: |
| * |
| * a) We can call scsi_io_completion_reprep(). The request will be |
| * unprepared and put back on the queue. Then a new command will |
| * be created for it. This should be used if we made forward |
| * progress, or if we want to switch from READ(10) to READ(6) for |
| * example. |
| * |
| * b) We can call scsi_io_completion_action(). The request will be |
| * put back on the queue and retried using the same command as |
| * before, possibly after a delay. |
| * |
| * c) We can call scsi_end_request() with blk_stat other than |
| * BLK_STS_OK, to fail the remainder of the request. |
| */ |
| void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) |
| { |
| int result = cmd->result; |
| struct request_queue *q = cmd->device->request_queue; |
| struct request *req = scsi_cmd_to_rq(cmd); |
| blk_status_t blk_stat = BLK_STS_OK; |
| |
| if (unlikely(result)) /* a nz result may or may not be an error */ |
| result = scsi_io_completion_nz_result(cmd, result, &blk_stat); |
| |
| if (unlikely(blk_rq_is_passthrough(req))) { |
| /* |
| * scsi_result_to_blk_status may have reset the host_byte |
| */ |
| scsi_req(req)->result = cmd->result; |
| } |
| |
| /* |
| * Next deal with any sectors which we were able to correctly |
| * handle. |
| */ |
| SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd, |
| "%u sectors total, %d bytes done.\n", |
| blk_rq_sectors(req), good_bytes)); |
| |
| /* |
| * Failed, zero length commands always need to drop down |
| * to retry code. Fast path should return in this block. |
| */ |
| if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) { |
| if (likely(!scsi_end_request(req, blk_stat, good_bytes))) |
| return; /* no bytes remaining */ |
| } |
| |
| /* Kill remainder if no retries. */ |
| if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) { |
| if (scsi_end_request(req, blk_stat, blk_rq_bytes(req))) |
| WARN_ONCE(true, |
| "Bytes remaining after failed, no-retry command"); |
| return; |
| } |
| |
| /* |
| * If there had been no error, but we have leftover bytes in the |
| * request just queue the command up again. |
| */ |
| if (likely(result == 0)) |
| scsi_io_completion_reprep(cmd, q); |
| else |
| scsi_io_completion_action(cmd, result); |
| } |
| |
| static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev, |
| struct request *rq) |
| { |
| return sdev->dma_drain_len && blk_rq_is_passthrough(rq) && |
| !op_is_write(req_op(rq)) && |
| sdev->host->hostt->dma_need_drain(rq); |
| } |
| |
| /** |
| * scsi_alloc_sgtables - Allocate and initialize data and integrity scatterlists |
| * @cmd: SCSI command data structure to initialize. |
| * |
| * Initializes @cmd->sdb and also @cmd->prot_sdb if data integrity is enabled |
| * for @cmd. |
| * |
| * Returns: |
| * * BLK_STS_OK - on success |
| * * BLK_STS_RESOURCE - if the failure is retryable |
| * * BLK_STS_IOERR - if the failure is fatal |
| */ |
| blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd) |
| { |
| struct scsi_device *sdev = cmd->device; |
| struct request *rq = scsi_cmd_to_rq(cmd); |
| unsigned short nr_segs = blk_rq_nr_phys_segments(rq); |
| struct scatterlist *last_sg = NULL; |
| blk_status_t ret; |
| bool need_drain = scsi_cmd_needs_dma_drain(sdev, rq); |
| int count; |
| |
| if (WARN_ON_ONCE(!nr_segs)) |
| return BLK_STS_IOERR; |
| |
| /* |
| * Make sure there is space for the drain. The driver must adjust |
| * max_hw_segments to be prepared for this. |
| */ |
| if (need_drain) |
| nr_segs++; |
| |
| /* |
| * If sg table allocation fails, requeue request later. |
| */ |
| if (unlikely(sg_alloc_table_chained(&cmd->sdb.table, nr_segs, |
| cmd->sdb.table.sgl, SCSI_INLINE_SG_CNT))) |
| return BLK_STS_RESOURCE; |
| |
| /* |
| * Next, walk the list, and fill in the addresses and sizes of |
| * each segment. |
| */ |
| count = __blk_rq_map_sg(rq->q, rq, cmd->sdb.table.sgl, &last_sg); |
| |
| if (blk_rq_bytes(rq) & rq->q->dma_pad_mask) { |
| unsigned int pad_len = |
| (rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1; |
| |
| last_sg->length += pad_len; |
| cmd->extra_len += pad_len; |
| } |
| |
| if (need_drain) { |
| sg_unmark_end(last_sg); |
| last_sg = sg_next(last_sg); |
| sg_set_buf(last_sg, sdev->dma_drain_buf, sdev->dma_drain_len); |
| sg_mark_end(last_sg); |
| |
| cmd->extra_len += sdev->dma_drain_len; |
| count++; |
| } |
| |
| BUG_ON(count > cmd->sdb.table.nents); |
| cmd->sdb.table.nents = count; |
| cmd->sdb.length = blk_rq_payload_bytes(rq); |
| |
| if (blk_integrity_rq(rq)) { |
| struct scsi_data_buffer *prot_sdb = cmd->prot_sdb; |
| int ivecs; |
| |
| if (WARN_ON_ONCE(!prot_sdb)) { |
| /* |
| * This can happen if someone (e.g. multipath) |
| * queues a command to a device on an adapter |
| * that does not support DIX. |
| */ |
| ret = BLK_STS_IOERR; |
| goto out_free_sgtables; |
| } |
| |
| ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio); |
| |
| if (sg_alloc_table_chained(&prot_sdb->table, ivecs, |
| prot_sdb->table.sgl, |
| SCSI_INLINE_PROT_SG_CNT)) { |
| ret = BLK_STS_RESOURCE; |
| goto out_free_sgtables; |
| } |
| |
| count = blk_rq_map_integrity_sg(rq->q, rq->bio, |
| prot_sdb->table.sgl); |
| BUG_ON(count > ivecs); |
| BUG_ON(count > queue_max_integrity_segments(rq->q)); |
| |
| cmd->prot_sdb = prot_sdb; |
| cmd->prot_sdb->table.nents = count; |
| } |
| |
| return BLK_STS_OK; |
| out_free_sgtables: |
| scsi_free_sgtables(cmd); |
| return ret; |
| } |
| EXPORT_SYMBOL(scsi_alloc_sgtables); |
| |
| /** |
| * scsi_initialize_rq - initialize struct scsi_cmnd partially |
| * @rq: Request associated with the SCSI command to be initialized. |
| * |
| * This function initializes the members of struct scsi_cmnd that must be |
| * initialized before request processing starts and that won't be |
| * reinitialized if a SCSI command is requeued. |
| */ |
| static void scsi_initialize_rq(struct request *rq) |
| { |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); |
| struct scsi_request *req = &cmd->req; |
| |
| memset(req->__cmd, 0, sizeof(req->__cmd)); |
| req->cmd = req->__cmd; |
| req->cmd_len = BLK_MAX_CDB; |
| req->sense_len = 0; |
| |
| init_rcu_head(&cmd->rcu); |
| cmd->jiffies_at_alloc = jiffies; |
| cmd->retries = 0; |
| } |
| |
| struct request *scsi_alloc_request(struct request_queue *q, |
| unsigned int op, blk_mq_req_flags_t flags) |
| { |
| struct request *rq; |
| |
| rq = blk_mq_alloc_request(q, op, flags); |
| if (!IS_ERR(rq)) |
| scsi_initialize_rq(rq); |
| return rq; |
| } |
| EXPORT_SYMBOL_GPL(scsi_alloc_request); |
| |
| /* |
| * Only called when the request isn't completed by SCSI, and not freed by |
| * SCSI |
| */ |
| static void scsi_cleanup_rq(struct request *rq) |
| { |
| if (rq->rq_flags & RQF_DONTPREP) { |
| scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq)); |
| rq->rq_flags &= ~RQF_DONTPREP; |
| } |
| } |
| |
| /* Called before a request is prepared. See also scsi_mq_prep_fn(). */ |
| void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd) |
| { |
| void *buf = cmd->sense_buffer; |
| void *prot = cmd->prot_sdb; |
| struct request *rq = scsi_cmd_to_rq(cmd); |
| unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS; |
| unsigned long jiffies_at_alloc; |
| int retries, to_clear; |
| bool in_flight; |
| int budget_token = cmd->budget_token; |
| |
| if (!blk_rq_is_passthrough(rq) && !(flags & SCMD_INITIALIZED)) { |
| flags |= SCMD_INITIALIZED; |
| scsi_initialize_rq(rq); |
| } |
| |
| jiffies_at_alloc = cmd->jiffies_at_alloc; |
| retries = cmd->retries; |
| in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state); |
| /* |
| * Zero out the cmd, except for the embedded scsi_request. Only clear |
| * the driver-private command data if the LLD does not supply a |
| * function to initialize that data. |
| */ |
| to_clear = sizeof(*cmd) - sizeof(cmd->req); |
| if (!dev->host->hostt->init_cmd_priv) |
| to_clear += dev->host->hostt->cmd_size; |
| memset((char *)cmd + sizeof(cmd->req), 0, to_clear); |
| |
| cmd->device = dev; |
| cmd->sense_buffer = buf; |
| cmd->prot_sdb = prot; |
| cmd->flags = flags; |
| INIT_LIST_HEAD(&cmd->eh_entry); |
| INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler); |
| cmd->jiffies_at_alloc = jiffies_at_alloc; |
| cmd->retries = retries; |
| if (in_flight) |
| __set_bit(SCMD_STATE_INFLIGHT, &cmd->state); |
| cmd->budget_token = budget_token; |
| |
| } |
| |
| static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev, |
| struct request *req) |
| { |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); |
| |
| /* |
| * Passthrough requests may transfer data, in which case they must |
| * a bio attached to them. Or they might contain a SCSI command |
| * that does not transfer data, in which case they may optionally |
| * submit a request without an attached bio. |
| */ |
| if (req->bio) { |
| blk_status_t ret = scsi_alloc_sgtables(cmd); |
| if (unlikely(ret != BLK_STS_OK)) |
| return ret; |
| } else { |
| BUG_ON(blk_rq_bytes(req)); |
| |
| memset(&cmd->sdb, 0, sizeof(cmd->sdb)); |
| } |
| |
| cmd->cmd_len = scsi_req(req)->cmd_len; |
| cmd->cmnd = scsi_req(req)->cmd; |
| cmd->transfersize = blk_rq_bytes(req); |
| cmd->allowed = scsi_req(req)->retries; |
| return BLK_STS_OK; |
| } |
| |
| static blk_status_t |
| scsi_device_state_check(struct scsi_device *sdev, struct request *req) |
| { |
| switch (sdev->sdev_state) { |
| case SDEV_CREATED: |
| return BLK_STS_OK; |
| case SDEV_OFFLINE: |
| case SDEV_TRANSPORT_OFFLINE: |
| /* |
| * If the device is offline we refuse to process any |
| * commands. The device must be brought online |
| * before trying any recovery commands. |
| */ |
| if (!sdev->offline_already) { |
| sdev->offline_already = true; |
| sdev_printk(KERN_ERR, sdev, |
| "rejecting I/O to offline device\n"); |
| } |
| return BLK_STS_IOERR; |
| case SDEV_DEL: |
| /* |
| * If the device is fully deleted, we refuse to |
| * process any commands as well. |
| */ |
| sdev_printk(KERN_ERR, sdev, |
| "rejecting I/O to dead device\n"); |
| return BLK_STS_IOERR; |
| case SDEV_BLOCK: |
| case SDEV_CREATED_BLOCK: |
| return BLK_STS_RESOURCE; |
| case SDEV_QUIESCE: |
| /* |
| * If the device is blocked we only accept power management |
| * commands. |
| */ |
| if (req && WARN_ON_ONCE(!(req->rq_flags & RQF_PM))) |
| return BLK_STS_RESOURCE; |
| return BLK_STS_OK; |
| default: |
| /* |
| * For any other not fully online state we only allow |
| * power management commands. |
| */ |
| if (req && !(req->rq_flags & RQF_PM)) |
| return BLK_STS_IOERR; |
| return BLK_STS_OK; |
| } |
| } |
| |
| /* |
| * scsi_dev_queue_ready: if we can send requests to sdev, assign one token |
| * and return the token else return -1. |
| */ |
| static inline int scsi_dev_queue_ready(struct request_queue *q, |
| struct scsi_device *sdev) |
| { |
| int token; |
| |
| token = sbitmap_get(&sdev->budget_map); |
| if (atomic_read(&sdev->device_blocked)) { |
| if (token < 0) |
| goto out; |
| |
| if (scsi_device_busy(sdev) > 1) |
| goto out_dec; |
| |
| /* |
| * unblock after device_blocked iterates to zero |
| */ |
| if (atomic_dec_return(&sdev->device_blocked) > 0) |
| goto out_dec; |
| SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev, |
| "unblocking device at zero depth\n")); |
| } |
| |
| return token; |
| out_dec: |
| if (token >= 0) |
| sbitmap_put(&sdev->budget_map, token); |
| out: |
| return -1; |
| } |
| |
| /* |
| * scsi_target_queue_ready: checks if there we can send commands to target |
| * @sdev: scsi device on starget to check. |
| */ |
| static inline int scsi_target_queue_ready(struct Scsi_Host *shost, |
| struct scsi_device *sdev) |
| { |
| struct scsi_target *starget = scsi_target(sdev); |
| unsigned int busy; |
| |
| if (starget->single_lun) { |
| spin_lock_irq(shost->host_lock); |
| if (starget->starget_sdev_user && |
| starget->starget_sdev_user != sdev) { |
| spin_unlock_irq(shost->host_lock); |
| return 0; |
| } |
| starget->starget_sdev_user = sdev; |
| spin_unlock_irq(shost->host_lock); |
| } |
| |
| if (starget->can_queue <= 0) |
| return 1; |
| |
| busy = atomic_inc_return(&starget->target_busy) - 1; |
| if (atomic_read(&starget->target_blocked) > 0) { |
| if (busy) |
| goto starved; |
| |
| /* |
| * unblock after target_blocked iterates to zero |
| */ |
| if (atomic_dec_return(&starget->target_blocked) > 0) |
| goto out_dec; |
| |
| SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget, |
| "unblocking target at zero depth\n")); |
| } |
| |
| if (busy >= starget->can_queue) |
| goto starved; |
| |
| return 1; |
| |
| starved: |
| spin_lock_irq(shost->host_lock); |
| list_move_tail(&sdev->starved_entry, &shost->starved_list); |
| spin_unlock_irq(shost->host_lock); |
| out_dec: |
| if (starget->can_queue > 0) |
| atomic_dec(&starget->target_busy); |
| return 0; |
| } |
| |
| /* |
| * scsi_host_queue_ready: if we can send requests to shost, return 1 else |
| * return 0. We must end up running the queue again whenever 0 is |
| * returned, else IO can hang. |
| */ |
| static inline int scsi_host_queue_ready(struct request_queue *q, |
| struct Scsi_Host *shost, |
| struct scsi_device *sdev, |
| struct scsi_cmnd *cmd) |
| { |
| if (scsi_host_in_recovery(shost)) |
| return 0; |
| |
| if (atomic_read(&shost->host_blocked) > 0) { |
| if (scsi_host_busy(shost) > 0) |
| goto starved; |
| |
| /* |
| * unblock after host_blocked iterates to zero |
| */ |
| if (atomic_dec_return(&shost->host_blocked) > 0) |
| goto out_dec; |
| |
| SCSI_LOG_MLQUEUE(3, |
| shost_printk(KERN_INFO, shost, |
| "unblocking host at zero depth\n")); |
| } |
| |
| if (shost->host_self_blocked) |
| goto starved; |
| |
| /* We're OK to process the command, so we can't be starved */ |
| if (!list_empty(&sdev->starved_entry)) { |
| spin_lock_irq(shost->host_lock); |
| if (!list_empty(&sdev->starved_entry)) |
| list_del_init(&sdev->starved_entry); |
| spin_unlock_irq(shost->host_lock); |
| } |
| |
| __set_bit(SCMD_STATE_INFLIGHT, &cmd->state); |
| |
| return 1; |
| |
| starved: |
| spin_lock_irq(shost->host_lock); |
| if (list_empty(&sdev->starved_entry)) |
| list_add_tail(&sdev->starved_entry, &shost->starved_list); |
| spin_unlock_irq(shost->host_lock); |
| out_dec: |
| scsi_dec_host_busy(shost, cmd); |
| return 0; |
| } |
| |
| /* |
| * Busy state exporting function for request stacking drivers. |
| * |
| * For efficiency, no lock is taken to check the busy state of |
| * shost/starget/sdev, since the returned value is not guaranteed and |
| * may be changed after request stacking drivers call the function, |
| * regardless of taking lock or not. |
| * |
| * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi |
| * needs to return 'not busy'. Otherwise, request stacking drivers |
| * may hold requests forever. |
| */ |
| static bool scsi_mq_lld_busy(struct request_queue *q) |
| { |
| struct scsi_device *sdev = q->queuedata; |
| struct Scsi_Host *shost; |
| |
| if (blk_queue_dying(q)) |
| return false; |
| |
| shost = sdev->host; |
| |
| /* |
| * Ignore host/starget busy state. |
| * Since block layer does not have a concept of fairness across |
| * multiple queues, congestion of host/starget needs to be handled |
| * in SCSI layer. |
| */ |
| if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev)) |
| return true; |
| |
| return false; |
| } |
| |
| /* |
| * Block layer request completion callback. May be called from interrupt |
| * context. |
| */ |
| static void scsi_complete(struct request *rq) |
| { |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); |
| enum scsi_disposition disposition; |
| |
| INIT_LIST_HEAD(&cmd->eh_entry); |
| |
| atomic_inc(&cmd->device->iodone_cnt); |
| if (cmd->result) |
| atomic_inc(&cmd->device->ioerr_cnt); |
| |
| disposition = scsi_decide_disposition(cmd); |
| if (disposition != SUCCESS && scsi_cmd_runtime_exceeced(cmd)) |
| disposition = SUCCESS; |
| |
| scsi_log_completion(cmd, disposition); |
| |
| switch (disposition) { |
| case SUCCESS: |
| scsi_finish_command(cmd); |
| break; |
| case NEEDS_RETRY: |
| scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY); |
| break; |
| case ADD_TO_MLQUEUE: |
| scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); |
| break; |
| default: |
| scsi_eh_scmd_add(cmd); |
| break; |
| } |
| } |
| |
| /** |
| * scsi_dispatch_cmd - Dispatch a command to the low-level driver. |
| * @cmd: command block we are dispatching. |
| * |
| * Return: nonzero return request was rejected and device's queue needs to be |
| * plugged. |
| */ |
| static int scsi_dispatch_cmd(struct scsi_cmnd *cmd) |
| { |
| struct Scsi_Host *host = cmd->device->host; |
| int rtn = 0; |
| |
| atomic_inc(&cmd->device->iorequest_cnt); |
| |
| /* check if the device is still usable */ |
| if (unlikely(cmd->device->sdev_state == SDEV_DEL)) { |
| /* in SDEV_DEL we error all commands. DID_NO_CONNECT |
| * returns an immediate error upwards, and signals |
| * that the device is no longer present */ |
| cmd->result = DID_NO_CONNECT << 16; |
| goto done; |
| } |
| |
| /* Check to see if the scsi lld made this device blocked. */ |
| if (unlikely(scsi_device_blocked(cmd->device))) { |
| /* |
| * in blocked state, the command is just put back on |
| * the device queue. The suspend state has already |
| * blocked the queue so future requests should not |
| * occur until the device transitions out of the |
| * suspend state. |
| */ |
| SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd, |
| "queuecommand : device blocked\n")); |
| return SCSI_MLQUEUE_DEVICE_BUSY; |
| } |
| |
| /* Store the LUN value in cmnd, if needed. */ |
| if (cmd->device->lun_in_cdb) |
| cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) | |
| (cmd->device->lun << 5 & 0xe0); |
| |
| scsi_log_send(cmd); |
| |
| /* |
| * Before we queue this command, check if the command |
| * length exceeds what the host adapter can handle. |
| */ |
| if (cmd->cmd_len > cmd->device->host->max_cmd_len) { |
| SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd, |
| "queuecommand : command too long. " |
| "cdb_size=%d host->max_cmd_len=%d\n", |
| cmd->cmd_len, cmd->device->host->max_cmd_len)); |
| cmd->result = (DID_ABORT << 16); |
| goto done; |
| } |
| |
| if (unlikely(host->shost_state == SHOST_DEL)) { |
| cmd->result = (DID_NO_CONNECT << 16); |
| goto done; |
| |
| } |
| |
| trace_scsi_dispatch_cmd_start(cmd); |
| rtn = host->hostt->queuecommand(host, cmd); |
| if (rtn) { |
| trace_scsi_dispatch_cmd_error(cmd, rtn); |
| if (rtn != SCSI_MLQUEUE_DEVICE_BUSY && |
| rtn != SCSI_MLQUEUE_TARGET_BUSY) |
| rtn = SCSI_MLQUEUE_HOST_BUSY; |
| |
| SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd, |
| "queuecommand : request rejected\n")); |
| } |
| |
| return rtn; |
| done: |
| scsi_done(cmd); |
| return 0; |
| } |
| |
| /* Size in bytes of the sg-list stored in the scsi-mq command-private data. */ |
| static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost) |
| { |
| return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) * |
| sizeof(struct scatterlist); |
| } |
| |
| static blk_status_t scsi_prepare_cmd(struct request *req) |
| { |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); |
| struct scsi_device *sdev = req->q->queuedata; |
| struct Scsi_Host *shost = sdev->host; |
| struct scatterlist *sg; |
| |
| scsi_init_command(sdev, cmd); |
| |
| cmd->prot_op = SCSI_PROT_NORMAL; |
| if (blk_rq_bytes(req)) |
| cmd->sc_data_direction = rq_dma_dir(req); |
| else |
| cmd->sc_data_direction = DMA_NONE; |
| |
| sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size; |
| cmd->sdb.table.sgl = sg; |
| |
| if (scsi_host_get_prot(shost)) { |
| memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer)); |
| |
| cmd->prot_sdb->table.sgl = |
| (struct scatterlist *)(cmd->prot_sdb + 1); |
| } |
| |
| /* |
| * Special handling for passthrough commands, which don't go to the ULP |
| * at all: |
| */ |
| if (blk_rq_is_passthrough(req)) |
| return scsi_setup_scsi_cmnd(sdev, req); |
| |
| if (sdev->handler && sdev->handler->prep_fn) { |
| blk_status_t ret = sdev->handler->prep_fn(sdev, req); |
| |
| if (ret != BLK_STS_OK) |
| return ret; |
| } |
| |
| cmd->cmnd = scsi_req(req)->cmd = scsi_req(req)->__cmd; |
| memset(cmd->cmnd, 0, BLK_MAX_CDB); |
| return scsi_cmd_to_driver(cmd)->init_command(cmd); |
| } |
| |
| void scsi_done(struct scsi_cmnd *cmd) |
| { |
| switch (cmd->submitter) { |
| case SUBMITTED_BY_BLOCK_LAYER: |
| break; |
| case SUBMITTED_BY_SCSI_ERROR_HANDLER: |
| return scsi_eh_done(cmd); |
| case SUBMITTED_BY_SCSI_RESET_IOCTL: |
| return; |
| } |
| |
| if (unlikely(blk_should_fake_timeout(scsi_cmd_to_rq(cmd)->q))) |
| return; |
| if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state))) |
| return; |
| trace_scsi_dispatch_cmd_done(cmd); |
| blk_mq_complete_request(scsi_cmd_to_rq(cmd)); |
| } |
| EXPORT_SYMBOL(scsi_done); |
| |
| static void scsi_mq_put_budget(struct request_queue *q, int budget_token) |
| { |
| struct scsi_device *sdev = q->queuedata; |
| |
| sbitmap_put(&sdev->budget_map, budget_token); |
| } |
| |
| static int scsi_mq_get_budget(struct request_queue *q) |
| { |
| struct scsi_device *sdev = q->queuedata; |
| int token = scsi_dev_queue_ready(q, sdev); |
| |
| if (token >= 0) |
| return token; |
| |
| atomic_inc(&sdev->restarts); |
| |
| /* |
| * Orders atomic_inc(&sdev->restarts) and atomic_read(&sdev->device_busy). |
| * .restarts must be incremented before .device_busy is read because the |
| * code in scsi_run_queue_async() depends on the order of these operations. |
| */ |
| smp_mb__after_atomic(); |
| |
| /* |
| * If all in-flight requests originated from this LUN are completed |
| * before reading .device_busy, sdev->device_busy will be observed as |
| * zero, then blk_mq_delay_run_hw_queues() will dispatch this request |
| * soon. Otherwise, completion of one of these requests will observe |
| * the .restarts flag, and the request queue will be run for handling |
| * this request, see scsi_end_request(). |
| */ |
| if (unlikely(scsi_device_busy(sdev) == 0 && |
| !scsi_device_blocked(sdev))) |
| blk_mq_delay_run_hw_queues(sdev->request_queue, SCSI_QUEUE_DELAY); |
| return -1; |
| } |
| |
| static void scsi_mq_set_rq_budget_token(struct request *req, int token) |
| { |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); |
| |
| cmd->budget_token = token; |
| } |
| |
| static int scsi_mq_get_rq_budget_token(struct request *req) |
| { |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); |
| |
| return cmd->budget_token; |
| } |
| |
| static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx, |
| const struct blk_mq_queue_data *bd) |
| { |
| struct request *req = bd->rq; |
| struct request_queue *q = req->q; |
| struct scsi_device *sdev = q->queuedata; |
| struct Scsi_Host *shost = sdev->host; |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req); |
| blk_status_t ret; |
| int reason; |
| |
| WARN_ON_ONCE(cmd->budget_token < 0); |
| |
| /* |
| * If the device is not in running state we will reject some or all |
| * commands. |
| */ |
| if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { |
| ret = scsi_device_state_check(sdev, req); |
| if (ret != BLK_STS_OK) |
| goto out_put_budget; |
| } |
| |
| ret = BLK_STS_RESOURCE; |
| if (!scsi_target_queue_ready(shost, sdev)) |
| goto out_put_budget; |
| if (!scsi_host_queue_ready(q, shost, sdev, cmd)) |
| goto out_dec_target_busy; |
| |
| if (!(req->rq_flags & RQF_DONTPREP)) { |
| ret = scsi_prepare_cmd(req); |
| if (ret != BLK_STS_OK) |
| goto out_dec_host_busy; |
| req->rq_flags |= RQF_DONTPREP; |
| } else { |
| clear_bit(SCMD_STATE_COMPLETE, &cmd->state); |
| } |
| |
| cmd->flags &= SCMD_PRESERVED_FLAGS; |
| if (sdev->simple_tags) |
| cmd->flags |= SCMD_TAGGED; |
| if (bd->last) |
| cmd->flags |= SCMD_LAST; |
| |
| scsi_set_resid(cmd, 0); |
| memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE); |
| cmd->submitter = SUBMITTED_BY_BLOCK_LAYER; |
| |
| blk_mq_start_request(req); |
| reason = scsi_dispatch_cmd(cmd); |
| if (reason) { |
| scsi_set_blocked(cmd, reason); |
| ret = BLK_STS_RESOURCE; |
| goto out_dec_host_busy; |
| } |
| |
| return BLK_STS_OK; |
| |
| out_dec_host_busy: |
| scsi_dec_host_busy(shost, cmd); |
| out_dec_target_busy: |
| if (scsi_target(sdev)->can_queue > 0) |
| atomic_dec(&scsi_target(sdev)->target_busy); |
| out_put_budget: |
| scsi_mq_put_budget(q, cmd->budget_token); |
| cmd->budget_token = -1; |
| switch (ret) { |
| case BLK_STS_OK: |
| break; |
| case BLK_STS_RESOURCE: |
| case BLK_STS_ZONE_RESOURCE: |
| if (scsi_device_blocked(sdev)) |
| ret = BLK_STS_DEV_RESOURCE; |
| break; |
| case BLK_STS_AGAIN: |
| scsi_req(req)->result = DID_BUS_BUSY << 16; |
| if (req->rq_flags & RQF_DONTPREP) |
| scsi_mq_uninit_cmd(cmd); |
| break; |
| default: |
| if (unlikely(!scsi_device_online(sdev))) |
| scsi_req(req)->result = DID_NO_CONNECT << 16; |
| else |
| scsi_req(req)->result = DID_ERROR << 16; |
| /* |
| * Make sure to release all allocated resources when |
| * we hit an error, as we will never see this command |
| * again. |
| */ |
| if (req->rq_flags & RQF_DONTPREP) |
| scsi_mq_uninit_cmd(cmd); |
| scsi_run_queue_async(sdev); |
| break; |
| } |
| return ret; |
| } |
| |
| static enum blk_eh_timer_return scsi_timeout(struct request *req, |
| bool reserved) |
| { |
| if (reserved) |
| return BLK_EH_RESET_TIMER; |
| return scsi_times_out(req); |
| } |
| |
| static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq, |
| unsigned int hctx_idx, unsigned int numa_node) |
| { |
| struct Scsi_Host *shost = set->driver_data; |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); |
| struct scatterlist *sg; |
| int ret = 0; |
| |
| cmd->sense_buffer = |
| kmem_cache_alloc_node(scsi_sense_cache, GFP_KERNEL, numa_node); |
| if (!cmd->sense_buffer) |
| return -ENOMEM; |
| cmd->req.sense = cmd->sense_buffer; |
| |
| if (scsi_host_get_prot(shost)) { |
| sg = (void *)cmd + sizeof(struct scsi_cmnd) + |
| shost->hostt->cmd_size; |
| cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost); |
| } |
| |
| if (shost->hostt->init_cmd_priv) { |
| ret = shost->hostt->init_cmd_priv(shost, cmd); |
| if (ret < 0) |
| kmem_cache_free(scsi_sense_cache, cmd->sense_buffer); |
| } |
| |
| return ret; |
| } |
| |
| static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq, |
| unsigned int hctx_idx) |
| { |
| struct Scsi_Host *shost = set->driver_data; |
| struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq); |
| |
| if (shost->hostt->exit_cmd_priv) |
| shost->hostt->exit_cmd_priv(shost, cmd); |
| kmem_cache_free(scsi_sense_cache, cmd->sense_buffer); |
| } |
| |
| |
| static int scsi_mq_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob) |
| { |
| struct Scsi_Host *shost = hctx->driver_data; |
| |
| if (shost->hostt->mq_poll) |
| return shost->hostt->mq_poll(shost, hctx->queue_num); |
| |
| return 0; |
| } |
| |
| static int scsi_init_hctx(struct blk_mq_hw_ctx *hctx, void *data, |
| unsigned int hctx_idx) |
| { |
| struct Scsi_Host *shost = data; |
| |
| hctx->driver_data = shost; |
| return 0; |
| } |
| |
| static int scsi_map_queues(struct blk_mq_tag_set *set) |
| { |
| struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set); |
| |
| if (shost->hostt->map_queues) |
| return shost->hostt->map_queues(shost); |
| return blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]); |
| } |
| |
| void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q) |
| { |
| struct device *dev = shost->dma_dev; |
| |
| /* |
| * this limit is imposed by hardware restrictions |
| */ |
| blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize, |
| SG_MAX_SEGMENTS)); |
| |
| if (scsi_host_prot_dma(shost)) { |
| shost->sg_prot_tablesize = |
| min_not_zero(shost->sg_prot_tablesize, |
| (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS); |
| BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize); |
| blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize); |
| } |
| |
| if (dev->dma_mask) { |
| shost->max_sectors = min_t(unsigned int, shost->max_sectors, |
| dma_max_mapping_size(dev) >> SECTOR_SHIFT); |
| } |
| blk_queue_max_hw_sectors(q, shost->max_sectors); |
| blk_queue_segment_boundary(q, shost->dma_boundary); |
| dma_set_seg_boundary(dev, shost->dma_boundary); |
| |
| blk_queue_max_segment_size(q, shost->max_segment_size); |
| blk_queue_virt_boundary(q, shost->virt_boundary_mask); |
| dma_set_max_seg_size(dev, queue_max_segment_size(q)); |
| |
| /* |
| * Set a reasonable default alignment: The larger of 32-byte (dword), |
| * which is a common minimum for HBAs, and the minimum DMA alignment, |
| * which is set by the platform. |
| * |
| * Devices that require a bigger alignment can increase it later. |
| */ |
| blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1); |
| } |
| EXPORT_SYMBOL_GPL(__scsi_init_queue); |
| |
| static const struct blk_mq_ops scsi_mq_ops_no_commit = { |
| .get_budget = scsi_mq_get_budget, |
| .put_budget = scsi_mq_put_budget, |
| .queue_rq = scsi_queue_rq, |
| .complete = scsi_complete, |
| .timeout = scsi_timeout, |
| #ifdef CONFIG_BLK_DEBUG_FS |
| .show_rq = scsi_show_rq, |
| #endif |
| .init_request = scsi_mq_init_request, |
| .exit_request = scsi_mq_exit_request, |
| .cleanup_rq = scsi_cleanup_rq, |
| .busy = scsi_mq_lld_busy, |
| .map_queues = scsi_map_queues, |
| .init_hctx = scsi_init_hctx, |
| .poll = scsi_mq_poll, |
| .set_rq_budget_token = scsi_mq_set_rq_budget_token, |
| .get_rq_budget_token = scsi_mq_get_rq_budget_token, |
| }; |
| |
| |
| static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx) |
| { |
| struct Scsi_Host *shost = hctx->driver_data; |
| |
| shost->hostt->commit_rqs(shost, hctx->queue_num); |
| } |
| |
| static const struct blk_mq_ops scsi_mq_ops = { |
| .get_budget = scsi_mq_get_budget, |
| .put_budget = scsi_mq_put_budget, |
| .queue_rq = scsi_queue_rq, |
| .commit_rqs = scsi_commit_rqs, |
| .complete = scsi_complete, |
| .timeout = scsi_timeout, |
| #ifdef CONFIG_BLK_DEBUG_FS |
| .show_rq = scsi_show_rq, |
| #endif |
| .init_request = scsi_mq_init_request, |
| .exit_request = scsi_mq_exit_request, |
| .cleanup_rq = scsi_cleanup_rq, |
| .busy = scsi_mq_lld_busy, |
| .map_queues = scsi_map_queues, |
| .init_hctx = scsi_init_hctx, |
| .poll = scsi_mq_poll, |
| .set_rq_budget_token = scsi_mq_set_rq_budget_token, |
| .get_rq_budget_token = scsi_mq_get_rq_budget_token, |
| }; |
| |
| int scsi_mq_setup_tags(struct Scsi_Host *shost) |
| { |
| unsigned int cmd_size, sgl_size; |
| struct blk_mq_tag_set *tag_set = &shost->tag_set; |
| |
| sgl_size = max_t(unsigned int, sizeof(struct scatterlist), |
| scsi_mq_inline_sgl_size(shost)); |
| cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size; |
| if (scsi_host_get_prot(shost)) |
| cmd_size += sizeof(struct scsi_data_buffer) + |
| sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT; |
| |
| memset(tag_set, 0, sizeof(*tag_set)); |
| if (shost->hostt->commit_rqs) |
| tag_set->ops = &scsi_mq_ops; |
| else |
| tag_set->ops = &scsi_mq_ops_no_commit; |
| tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1; |
| tag_set->nr_maps = shost->nr_maps ? : 1; |
| tag_set->queue_depth = shost->can_queue; |
| tag_set->cmd_size = cmd_size; |
| tag_set->numa_node = NUMA_NO_NODE; |
| tag_set->flags = BLK_MQ_F_SHOULD_MERGE; |
| tag_set->flags |= |
| BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy); |
| tag_set->driver_data = shost; |
| if (shost->host_tagset) |
| tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED; |
| |
| return blk_mq_alloc_tag_set(tag_set); |
| } |
| |
| void scsi_mq_destroy_tags(struct Scsi_Host *shost) |
| { |
| blk_mq_free_tag_set(&shost->tag_set); |
| } |
| |
| /** |
| * scsi_device_from_queue - return sdev associated with a request_queue |
| * @q: The request queue to return the sdev from |
| * |
| * Return the sdev associated with a request queue or NULL if the |
| * request_queue does not reference a SCSI device. |
| */ |
| struct scsi_device *scsi_device_from_queue(struct request_queue *q) |
| { |
| struct scsi_device *sdev = NULL; |
| |
| if (q->mq_ops == &scsi_mq_ops_no_commit || |
| q->mq_ops == &scsi_mq_ops) |
| sdev = q->queuedata; |
| if (!sdev || !get_device(&sdev->sdev_gendev)) |
| sdev = NULL; |
| |
| return sdev; |
| } |
| /* |
| * pktcdvd should have been integrated into the SCSI layers, but for historical |
| * reasons like the old IDE driver it isn't. This export allows it to safely |
| * probe if a given device is a SCSI one and only attach to that. |
| */ |
| #ifdef CONFIG_CDROM_PKTCDVD_MODULE |
| EXPORT_SYMBOL_GPL(scsi_device_from_queue); |
| #endif |
| |
| /** |
| * scsi_block_requests - Utility function used by low-level drivers to prevent |
| * further commands from being queued to the device. |
| * @shost: host in question |
| * |
| * There is no timer nor any other means by which the requests get unblocked |
| * other than the low-level driver calling scsi_unblock_requests(). |
| */ |
| void scsi_block_requests(struct Scsi_Host *shost) |
| { |
| shost->host_self_blocked = 1; |
| } |
| EXPORT_SYMBOL(scsi_block_requests); |
| |
| /** |
| * scsi_unblock_requests - Utility function used by low-level drivers to allow |
| * further commands to be queued to the device. |
| * @shost: host in question |
| * |
| * There is no timer nor any other means by which the requests get unblocked |
| * other than the low-level driver calling scsi_unblock_requests(). This is done |
| * as an API function so that changes to the internals of the scsi mid-layer |
| * won't require wholesale changes to drivers that use this feature. |
| */ |
| void scsi_unblock_requests(struct Scsi_Host *shost) |
| { |
| shost->host_self_blocked = 0; |
| scsi_run_host_queues(shost); |
| } |
| EXPORT_SYMBOL(scsi_unblock_requests); |
| |
| void scsi_exit_queue(void) |
| { |
| kmem_cache_destroy(scsi_sense_cache); |
| } |
| |
| /** |
| * scsi_mode_select - issue a mode select |
| * @sdev: SCSI device to be queried |
| * @pf: Page format bit (1 == standard, 0 == vendor specific) |
| * @sp: Save page bit (0 == don't save, 1 == save) |
| * @modepage: mode page being requested |
| * @buffer: request buffer (may not be smaller than eight bytes) |
| * @len: length of request buffer. |
| * @timeout: command timeout |
| * @retries: number of retries before failing |
| * @data: returns a structure abstracting the mode header data |
| * @sshdr: place to put sense data (or NULL if no sense to be collected). |
| * must be SCSI_SENSE_BUFFERSIZE big. |
| * |
| * Returns zero if successful; negative error number or scsi |
| * status on error |
| * |
| */ |
| int |
| scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage, |
| unsigned char *buffer, int len, int timeout, int retries, |
| struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) |
| { |
| unsigned char cmd[10]; |
| unsigned char *real_buffer; |
| int ret; |
| |
| memset(cmd, 0, sizeof(cmd)); |
| cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0); |
| |
| /* |
| * Use MODE SELECT(10) if the device asked for it or if the mode page |
| * and the mode select header cannot fit within the maximumm 255 bytes |
| * of the MODE SELECT(6) command. |
| */ |
| if (sdev->use_10_for_ms || |
| len + 4 > 255 || |
| data->block_descriptor_length > 255) { |
| if (len > 65535 - 8) |
| return -EINVAL; |
| real_buffer = kmalloc(8 + len, GFP_KERNEL); |
| if (!real_buffer) |
| return -ENOMEM; |
| memcpy(real_buffer + 8, buffer, len); |
| len += 8; |
| real_buffer[0] = 0; |
| real_buffer[1] = 0; |
| real_buffer[2] = data->medium_type; |
| real_buffer[3] = data->device_specific; |
| real_buffer[4] = data->longlba ? 0x01 : 0; |
| real_buffer[5] = 0; |
| put_unaligned_be16(data->block_descriptor_length, |
| &real_buffer[6]); |
| |
| cmd[0] = MODE_SELECT_10; |
| put_unaligned_be16(len, &cmd[7]); |
| } else { |
| if (data->longlba) |
| return -EINVAL; |
| |
| real_buffer = kmalloc(4 + len, GFP_KERNEL); |
| if (!real_buffer) |
| return -ENOMEM; |
| memcpy(real_buffer + 4, buffer, len); |
| len += 4; |
| real_buffer[0] = 0; |
| real_buffer[1] = data->medium_type; |
| real_buffer[2] = data->device_specific; |
| real_buffer[3] = data->block_descriptor_length; |
| |
| cmd[0] = MODE_SELECT; |
| cmd[4] = len; |
| } |
| |
| ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len, |
| sshdr, timeout, retries, NULL); |
| kfree(real_buffer); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(scsi_mode_select); |
| |
| /** |
| * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary. |
| * @sdev: SCSI device to be queried |
| * @dbd: set to prevent mode sense from returning block descriptors |
| * @modepage: mode page being requested |
| * @buffer: request buffer (may not be smaller than eight bytes) |
| * @len: length of request buffer. |
| * @timeout: command timeout |
| * @retries: number of retries before failing |
| * @data: returns a structure abstracting the mode header data |
| * @sshdr: place to put sense data (or NULL if no sense to be collected). |
| * must be SCSI_SENSE_BUFFERSIZE big. |
| * |
| * Returns zero if successful, or a negative error number on failure |
| */ |
| int |
| scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, |
| unsigned char *buffer, int len, int timeout, int retries, |
| struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) |
| { |
| unsigned char cmd[12]; |
| int use_10_for_ms; |
| int header_length; |
| int result, retry_count = retries; |
| struct scsi_sense_hdr my_sshdr; |
| |
| memset(data, 0, sizeof(*data)); |
| memset(&cmd[0], 0, 12); |
| |
| dbd = sdev->set_dbd_for_ms ? 8 : dbd; |
| cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ |
| cmd[2] = modepage; |
| |
| /* caller might not be interested in sense, but we need it */ |
| if (!sshdr) |
| sshdr = &my_sshdr; |
| |
| retry: |
| use_10_for_ms = sdev->use_10_for_ms || len > 255; |
| |
| if (use_10_for_ms) { |
| if (len < 8 || len > 65535) |
| return -EINVAL; |
| |
| cmd[0] = MODE_SENSE_10; |
| put_unaligned_be16(len, &cmd[7]); |
| header_length = 8; |
| } else { |
| if (len < 4) |
| return -EINVAL; |
| |
| cmd[0] = MODE_SENSE; |
| cmd[4] = len; |
| header_length = 4; |
| } |
| |
| memset(buffer, 0, len); |
| |
| result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, |
| sshdr, timeout, retries, NULL); |
| if (result < 0) |
| return result; |
| |
| /* This code looks awful: what it's doing is making sure an |
| * ILLEGAL REQUEST sense return identifies the actual command |
| * byte as the problem. MODE_SENSE commands can return |
| * ILLEGAL REQUEST if the code page isn't supported */ |
| |
| if (!scsi_status_is_good(result)) { |
| if (scsi_sense_valid(sshdr)) { |
| if ((sshdr->sense_key == ILLEGAL_REQUEST) && |
| (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { |
| /* |
| * Invalid command operation code: retry using |
| * MODE SENSE(6) if this was a MODE SENSE(10) |
| * request, except if the request mode page is |
| * too large for MODE SENSE single byte |
| * allocation length field. |
| */ |
| if (use_10_for_ms) { |
| if (len > 255) |
| return -EIO; |
| sdev->use_10_for_ms = 0; |
| goto retry; |
| } |
| } |
| if (scsi_status_is_check_condition(result) && |
| sshdr->sense_key == UNIT_ATTENTION && |
| retry_count) { |
| retry_count--; |
| goto retry; |
| } |
| } |
| return -EIO; |
| } |
| if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b && |
| (modepage == 6 || modepage == 8))) { |
| /* Initio breakage? */ |
| header_length = 0; |
| data->length = 13; |
| data->medium_type = 0; |
| data->device_specific = 0; |
| data->longlba = 0; |
| data->block_descriptor_length = 0; |
| } else if (use_10_for_ms) { |
| data->length = get_unaligned_be16(&buffer[0]) + 2; |
| data->medium_type = buffer[2]; |
| data->device_specific = buffer[3]; |
| data->longlba = buffer[4] & 0x01; |
| data->block_descriptor_length = get_unaligned_be16(&buffer[6]); |
| } else { |
| data->length = buffer[0] + 1; |
| data->medium_type = buffer[1]; |
| data->device_specific = buffer[2]; |
| data->block_descriptor_length = buffer[3]; |
| } |
| data->header_length = header_length; |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(scsi_mode_sense); |
| |
| /** |
| * scsi_test_unit_ready - test if unit is ready |
| * @sdev: scsi device to change the state of. |
| * @timeout: command timeout |
| * @retries: number of retries before failing |
| * @sshdr: outpout pointer for decoded sense information. |
| * |
| * Returns zero if unsuccessful or an error if TUR failed. For |
| * removable media, UNIT_ATTENTION sets ->changed flag. |
| **/ |
| int |
| scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries, |
| struct scsi_sense_hdr *sshdr) |
| { |
| char cmd[] = { |
| TEST_UNIT_READY, 0, 0, 0, 0, 0, |
| }; |
| int result; |
| |
| /* try to eat the UNIT_ATTENTION if there are enough retries */ |
| do { |
| result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr, |
| timeout, 1, NULL); |
| if (sdev->removable && scsi_sense_valid(sshdr) && |
| sshdr->sense_key == UNIT_ATTENTION) |
| sdev->changed = 1; |
| } while (scsi_sense_valid(sshdr) && |
| sshdr->sense_key == UNIT_ATTENTION && --retries); |
| |
| return result; |
| } |
| EXPORT_SYMBOL(scsi_test_unit_ready); |
| |
| /** |
| * scsi_device_set_state - Take the given device through the device state model. |
| * @sdev: scsi device to change the state of. |
| * @state: state to change to. |
| * |
| * Returns zero if successful or an error if the requested |
| * transition is illegal. |
| */ |
| int |
| scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) |
| { |
| enum scsi_device_state oldstate = sdev->sdev_state; |
| |
| if (state == oldstate) |
| return 0; |
| |
| switch (state) { |
| case SDEV_CREATED: |
| switch (oldstate) { |
| case SDEV_CREATED_BLOCK: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_RUNNING: |
| switch (oldstate) { |
| case SDEV_CREATED: |
| case SDEV_OFFLINE: |
| case SDEV_TRANSPORT_OFFLINE: |
| case SDEV_QUIESCE: |
| case SDEV_BLOCK: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_QUIESCE: |
| switch (oldstate) { |
| case SDEV_RUNNING: |
| case SDEV_OFFLINE: |
| case SDEV_TRANSPORT_OFFLINE: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_OFFLINE: |
| case SDEV_TRANSPORT_OFFLINE: |
| switch (oldstate) { |
| case SDEV_CREATED: |
| case SDEV_RUNNING: |
| case SDEV_QUIESCE: |
| case SDEV_BLOCK: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_BLOCK: |
| switch (oldstate) { |
| case SDEV_RUNNING: |
| case SDEV_CREATED_BLOCK: |
| case SDEV_QUIESCE: |
| case SDEV_OFFLINE: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_CREATED_BLOCK: |
| switch (oldstate) { |
| case SDEV_CREATED: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_CANCEL: |
| switch (oldstate) { |
| case SDEV_CREATED: |
| case SDEV_RUNNING: |
| case SDEV_QUIESCE: |
| case SDEV_OFFLINE: |
| case SDEV_TRANSPORT_OFFLINE: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| case SDEV_DEL: |
| switch (oldstate) { |
| case SDEV_CREATED: |
| case SDEV_RUNNING: |
| case SDEV_OFFLINE: |
| case SDEV_TRANSPORT_OFFLINE: |
| case SDEV_CANCEL: |
| case SDEV_BLOCK: |
| case SDEV_CREATED_BLOCK: |
| break; |
| default: |
| goto illegal; |
| } |
| break; |
| |
| } |
| sdev->offline_already = false; |
| sdev->sdev_state = state; |
| return 0; |
| |
| illegal: |
| SCSI_LOG_ERROR_RECOVERY(1, |
| sdev_printk(KERN_ERR, sdev, |
| "Illegal state transition %s->%s", |
| scsi_device_state_name(oldstate), |
| scsi_device_state_name(state)) |
| ); |
| return -EINVAL; |
| } |
| EXPORT_SYMBOL(scsi_device_set_state); |
| |
| /** |
| * scsi_evt_emit - emit a single SCSI device uevent |
| * @sdev: associated SCSI device |
| * @evt: event to emit |
| * |
| * Send a single uevent (scsi_event) to the associated scsi_device. |
| */ |
| static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt) |
| { |
| int idx = 0; |
| char *envp[3]; |
| |
| switch (evt->evt_type) { |
| case SDEV_EVT_MEDIA_CHANGE: |
| envp[idx++] = "SDEV_MEDIA_CHANGE=1"; |
| break; |
| case SDEV_EVT_INQUIRY_CHANGE_REPORTED: |
| scsi_rescan_device(&sdev->sdev_gendev); |
| envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED"; |
| break; |
| case SDEV_EVT_CAPACITY_CHANGE_REPORTED: |
| envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED"; |
| break; |
| case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED: |
| envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED"; |
| break; |
| case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED: |
| envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED"; |
| break; |
| case SDEV_EVT_LUN_CHANGE_REPORTED: |
| envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED"; |
| break; |
| case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED: |
| envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED"; |
| break; |
| case SDEV_EVT_POWER_ON_RESET_OCCURRED: |
| envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED"; |
| break; |
| default: |
| /* do nothing */ |
| break; |
| } |
| |
| envp[idx++] = NULL; |
| |
| kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp); |
| } |
| |
| /** |
| * scsi_evt_thread - send a uevent for each scsi event |
| * @work: work struct for scsi_device |
| * |
| * Dispatch queued events to their associated scsi_device kobjects |
| * as uevents. |
| */ |
| void scsi_evt_thread(struct work_struct *work) |
| { |
| struct scsi_device *sdev; |
| enum scsi_device_event evt_type; |
| LIST_HEAD(event_list); |
| |
| sdev = container_of(work, struct scsi_device, event_work); |
| |
| for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++) |
| if (test_and_clear_bit(evt_type, sdev->pending_events)) |
| sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL); |
| |
| while (1) { |
| struct scsi_event *evt; |
| struct list_head *this, *tmp; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&sdev->list_lock, flags); |
| list_splice_init(&sdev->event_list, &event_list); |
| spin_unlock_irqrestore(&sdev->list_lock, flags); |
| |
| if (list_empty(&event_list)) |
| break; |
| |
| list_for_each_safe(this, tmp, &event_list) { |
| evt = list_entry(this, struct scsi_event, node); |
| list_del(&evt->node); |
| scsi_evt_emit(sdev, evt); |
| kfree(evt); |
| } |
| } |
| } |
| |
| /** |
| * sdev_evt_send - send asserted event to uevent thread |
| * @sdev: scsi_device event occurred on |
| * @evt: event to send |
| * |
| * Assert scsi device event asynchronously. |
| */ |
| void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt) |
| { |
| unsigned long flags; |
| |
| #if 0 |
| /* FIXME: currently this check eliminates all media change events |
| * for polled devices. Need to update to discriminate between AN |
| * and polled events */ |
| if (!test_bit(evt->evt_type, sdev->supported_events)) { |
| kfree(evt); |
| return; |
| } |
| #endif |
| |
| spin_lock_irqsave(&sdev->list_lock, flags); |
| list_add_tail(&evt->node, &sdev->event_list); |
| schedule_work(&sdev->event_work); |
| spin_unlock_irqrestore(&sdev->list_lock, flags); |
| } |
| EXPORT_SYMBOL_GPL(sdev_evt_send); |
| |
| /** |
| * sdev_evt_alloc - allocate a new scsi event |
| * @evt_type: type of event to allocate |
| * @gfpflags: GFP flags for allocation |
| * |
| * Allocates and returns a new scsi_event. |
| */ |
| struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type, |
| gfp_t gfpflags) |
| { |
| struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags); |
| if (!evt) |
| return NULL; |
| |
| evt->evt_type = evt_type; |
| INIT_LIST_HEAD(&evt->node); |
| |
| /* evt_type-specific initialization, if any */ |
| switch (evt_type) { |
| case SDEV_EVT_MEDIA_CHANGE: |
| case SDEV_EVT_INQUIRY_CHANGE_REPORTED: |
| case SDEV_EVT_CAPACITY_CHANGE_REPORTED: |
| case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED: |
| case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED: |
| case SDEV_EVT_LUN_CHANGE_REPORTED: |
| case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED: |
| case SDEV_EVT_POWER_ON_RESET_OCCURRED: |
| default: |
| /* do nothing */ |
| break; |
| } |
| |
| return evt; |
| } |
| EXPORT_SYMBOL_GPL(sdev_evt_alloc); |
| |
| /** |
| * sdev_evt_send_simple - send asserted event to uevent thread |
| * @sdev: scsi_device event occurred on |
| * @evt_type: type of event to send |
| * @gfpflags: GFP flags for allocation |
| * |
| * Assert scsi device event asynchronously, given an event type. |
| */ |
| void sdev_evt_send_simple(struct scsi_device *sdev, |
| enum scsi_device_event evt_type, gfp_t gfpflags) |
| { |
| struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags); |
| if (!evt) { |
| sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n", |
| evt_type); |
| return; |
| } |
| |
| sdev_evt_send(sdev, evt); |
| } |
| EXPORT_SYMBOL_GPL(sdev_evt_send_simple); |
| |
| /** |
| * scsi_device_quiesce - Block all commands except power management. |
| * @sdev: scsi device to quiesce. |
| * |
| * This works by trying to transition to the SDEV_QUIESCE state |
| * (which must be a legal transition). When the device is in this |
| * state, only power management requests will be accepted, all others will |
| * be deferred. |
| * |
| * Must be called with user context, may sleep. |
| * |
| * Returns zero if unsuccessful or an error if not. |
| */ |
| int |
| scsi_device_quiesce(struct scsi_device *sdev) |
| { |
| struct request_queue *q = sdev->request_queue; |
| int err; |
| |
| /* |
| * It is allowed to call scsi_device_quiesce() multiple times from |
| * the same context but concurrent scsi_device_quiesce() calls are |
| * not allowed. |
| */ |
| WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current); |
| |
| if (sdev->quiesced_by == current) |
| return 0; |
| |
| blk_set_pm_only(q); |
| |
| blk_mq_freeze_queue(q); |
| /* |
| * Ensure that the effect of blk_set_pm_only() will be visible |
| * for percpu_ref_tryget() callers that occur after the queue |
| * unfreeze even if the queue was already frozen before this function |
| * was called. See also https://lwn.net/Articles/573497/. |
| */ |
| synchronize_rcu(); |
| blk_mq_unfreeze_queue(q); |
| |
| mutex_lock(&sdev->state_mutex); |
| err = scsi_device_set_state(sdev, SDEV_QUIESCE); |
| if (err == 0) |
| sdev->quiesced_by = current; |
| else |
| blk_clear_pm_only(q); |
| mutex_unlock(&sdev->state_mutex); |
| |
| return err; |
| } |
| EXPORT_SYMBOL(scsi_device_quiesce); |
| |
| /** |
| * scsi_device_resume - Restart user issued commands to a quiesced device. |
| * @sdev: scsi device to resume. |
| * |
| * Moves the device from quiesced back to running and restarts the |
| * queues. |
| * |
| * Must be called with user context, may sleep. |
| */ |
| void scsi_device_resume(struct scsi_device *sdev) |
| { |
| /* check if the device state was mutated prior to resume, and if |
| * so assume the state is being managed elsewhere (for example |
| * device deleted during suspend) |
| */ |
| mutex_lock(&sdev->state_mutex); |
| if (sdev->sdev_state == SDEV_QUIESCE) |
| scsi_device_set_state(sdev, SDEV_RUNNING); |
| if (sdev->quiesced_by) { |
| sdev->quiesced_by = NULL; |
| blk_clear_pm_only(sdev->request_queue); |
| } |
| mutex_unlock(&sdev->state_mutex); |
| } |
| EXPORT_SYMBOL(scsi_device_resume); |
| |
| static void |
| device_quiesce_fn(struct scsi_device *sdev, void *data) |
| { |
| scsi_device_quiesce(sdev); |
| } |
| |
| void |
| scsi_target_quiesce(struct scsi_target *starget) |
| { |
| starget_for_each_device(starget, NULL, device_quiesce_fn); |
| } |
| EXPORT_SYMBOL(scsi_target_quiesce); |
| |
| static void |
| device_resume_fn(struct scsi_device *sdev, void *data) |
| { |
| scsi_device_resume(sdev); |
| } |
| |
| void |
| scsi_target_resume(struct scsi_target *starget) |
| { |
| starget_for_each_device(starget, NULL, device_resume_fn); |
| } |
| EXPORT_SYMBOL(scsi_target_resume); |
| |
| static int __scsi_internal_device_block_nowait(struct scsi_device *sdev) |
| { |
| if (scsi_device_set_state(sdev, SDEV_BLOCK)) |
| return scsi_device_set_state(sdev, SDEV_CREATED_BLOCK); |
| |
| return 0; |
| } |
| |
| void scsi_start_queue(struct scsi_device *sdev) |
| { |
| if (cmpxchg(&sdev->queue_stopped, 1, 0)) |
| blk_mq_unquiesce_queue(sdev->request_queue); |
| } |
| |
| static void scsi_stop_queue(struct scsi_device *sdev, bool nowait) |
| { |
| /* |
| * The atomic variable of ->queue_stopped covers that |
| * blk_mq_quiesce_queue* is balanced with blk_mq_unquiesce_queue. |
| * |
| * However, we still need to wait until quiesce is done |
| * in case that queue has been stopped. |
| */ |
| if (!cmpxchg(&sdev->queue_stopped, 0, 1)) { |
| if (nowait) |
| blk_mq_quiesce_queue_nowait(sdev->request_queue); |
| else |
| blk_mq_quiesce_queue(sdev->request_queue); |
| } else { |
| if (!nowait) |
| blk_mq_wait_quiesce_done(sdev->request_queue); |
| } |
| } |
| |
| /** |
| * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state |
| * @sdev: device to block |
| * |
| * Pause SCSI command processing on the specified device. Does not sleep. |
| * |
| * Returns zero if successful or a negative error code upon failure. |
| * |
| * Notes: |
| * This routine transitions the device to the SDEV_BLOCK state (which must be |
| * a legal transition). When the device is in this state, command processing |
| * is paused until the device leaves the SDEV_BLOCK state. See also |
| * scsi_internal_device_unblock_nowait(). |
| */ |
| int scsi_internal_device_block_nowait(struct scsi_device *sdev) |
| { |
| int ret = __scsi_internal_device_block_nowait(sdev); |
| |
| /* |
| * The device has transitioned to SDEV_BLOCK. Stop the |
| * block layer from calling the midlayer with this device's |
| * request queue. |
| */ |
| if (!ret) |
| scsi_stop_queue(sdev, true); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait); |
| |
| /** |
| * scsi_internal_device_block - try to transition to the SDEV_BLOCK state |
| * @sdev: device to block |
| * |
| * Pause SCSI command processing on the specified device and wait until all |
| * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep. |
| * |
| * Returns zero if successful or a negative error code upon failure. |
| * |
| * Note: |
| * This routine transitions the device to the SDEV_BLOCK state (which must be |
| * a legal transition). When the device is in this state, command processing |
| * is paused until the device leaves the SDEV_BLOCK state. See also |
| * scsi_internal_device_unblock(). |
| */ |
| static int scsi_internal_device_block(struct scsi_device *sdev) |
| { |
| int err; |
| |
| mutex_lock(&sdev->state_mutex); |
| err = __scsi_internal_device_block_nowait(sdev); |
| if (err == 0) |
| scsi_stop_queue(sdev, false); |
| mutex_unlock(&sdev->state_mutex); |
| |
| return err; |
| } |
| |
| /** |
| * scsi_internal_device_unblock_nowait - resume a device after a block request |
| * @sdev: device to resume |
| * @new_state: state to set the device to after unblocking |
| * |
| * Restart the device queue for a previously suspended SCSI device. Does not |
| * sleep. |
| * |
| * Returns zero if successful or a negative error code upon failure. |
| * |
| * Notes: |
| * This routine transitions the device to the SDEV_RUNNING state or to one of |
| * the offline states (which must be a legal transition) allowing the midlayer |
| * to goose the queue for this device. |
| */ |
| int scsi_internal_device_unblock_nowait(struct scsi_device *sdev, |
| enum scsi_device_state new_state) |
| { |
| switch (new_state) { |
| case SDEV_RUNNING: |
| case SDEV_TRANSPORT_OFFLINE: |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| /* |
| * Try to transition the scsi device to SDEV_RUNNING or one of the |
| * offlined states and goose the device queue if successful. |
| */ |
| switch (sdev->sdev_state) { |
| case SDEV_BLOCK: |
| case SDEV_TRANSPORT_OFFLINE: |
| sdev->sdev_state = new_state; |
| break; |
| case SDEV_CREATED_BLOCK: |
| if (new_state == SDEV_TRANSPORT_OFFLINE || |
| new_state == SDEV_OFFLINE) |
| sdev->sdev_state = new_state; |
| else |
| sdev->sdev_state = SDEV_CREATED; |
| break; |
| case SDEV_CANCEL: |
| case SDEV_OFFLINE: |
| break; |
| default: |
| return -EINVAL; |
| } |
| scsi_start_queue(sdev); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait); |
| |
| /** |
| * scsi_internal_device_unblock - resume a device after a block request |
| * @sdev: device to resume |
| * @new_state: state to set the device to after unblocking |
| * |
| * Restart the device queue for a previously suspended SCSI device. May sleep. |
| * |
| * Returns zero if successful or a negative error code upon failure. |
| * |
| * Notes: |
| * This routine transitions the device to the SDEV_RUNNING state or to one of |
| * the offline states (which must be a legal transition) allowing the midlayer |
| * to goose the queue for this device. |
| */ |
| static int scsi_internal_device_unblock(struct scsi_device *sdev, |
| enum scsi_device_state new_state) |
| { |
| int ret; |
| |
| mutex_lock(&sdev->state_mutex); |
| ret = scsi_internal_device_unblock_nowait(sdev, new_state); |
| mutex_unlock(&sdev->state_mutex); |
| |
| return ret; |
| } |
| |
| static void |
| device_block(struct scsi_device *sdev, void *data) |
| { |
| int ret; |
| |
| ret = scsi_internal_device_block(sdev); |
| |
| WARN_ONCE(ret, "scsi_internal_device_block(%s) failed: ret = %d\n", |
| dev_name(&sdev->sdev_gendev), ret); |
| } |
| |
| static int |
| target_block(struct device *dev, void *data) |
| { |
| if (scsi_is_target_device(dev)) |
| starget_for_each_device(to_scsi_target(dev), NULL, |
| device_block); |
| return 0; |
| } |
| |
| void |
| scsi_target_block(struct device *dev) |
| { |
| if (scsi_is_target_device(dev)) |
| starget_for_each_device(to_scsi_target(dev), NULL, |
| device_block); |
| else |
| device_for_each_child(dev, NULL, target_block); |
| } |
| EXPORT_SYMBOL_GPL(scsi_target_block); |
| |
| static void |
| device_unblock(struct scsi_device *sdev, void *data) |
| { |
| scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data); |
| } |
| |
| static int |
| target_unblock(struct device *dev, void *data) |
| { |
| if (scsi_is_target_device(dev)) |
| starget_for_each_device(to_scsi_target(dev), data, |
| device_unblock); |
| return 0; |
| } |
| |
| void |
| scsi_target_unblock(struct device *dev, enum scsi_device_state new_state) |
| { |
| if (scsi_is_target_device(dev)) |
| starget_for_each_device(to_scsi_target(dev), &new_state, |
| device_unblock); |
| else |
| device_for_each_child(dev, &new_state, target_unblock); |
| } |
| EXPORT_SYMBOL_GPL(scsi_target_unblock); |
| |
| int |
| scsi_host_block(struct Scsi_Host *shost) |
| { |
| struct scsi_device *sdev; |
| int ret = 0; |
| |
| /* |
| * Call scsi_internal_device_block_nowait so we can avoid |
| * calling synchronize_rcu() for each LUN. |
| */ |
| shost_for_each_device(sdev, shost) { |
| mutex_lock(&sdev->state_mutex); |
| ret = scsi_internal_device_block_nowait(sdev); |
| mutex_unlock(&sdev->state_mutex); |
| if (ret) { |
| scsi_device_put(sdev); |
| break; |
| } |
| } |
| |
| /* |
| * SCSI never enables blk-mq's BLK_MQ_F_BLOCKING flag so |
| * calling synchronize_rcu() once is enough. |
| */ |
| WARN_ON_ONCE(shost->tag_set.flags & BLK_MQ_F_BLOCKING); |
| |
| if (!ret) |
| synchronize_rcu(); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(scsi_host_block); |
| |
| int |
| scsi_host_unblock(struct Scsi_Host *shost, int new_state) |
| { |
| struct scsi_device *sdev; |
| int ret = 0; |
| |
| shost_for_each_device(sdev, shost) { |
| ret = scsi_internal_device_unblock(sdev, new_state); |
| if (ret) { |
| scsi_device_put(sdev); |
| break; |
| } |
| } |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(scsi_host_unblock); |
| |
| /** |
| * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt |
| * @sgl: scatter-gather list |
| * @sg_count: number of segments in sg |
| * @offset: offset in bytes into sg, on return offset into the mapped area |
| * @len: bytes to map, on return number of bytes mapped |
| * |
| * Returns virtual address of the start of the mapped page |
| */ |
| void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count, |
| size_t *offset, size_t *len) |
| { |
| int i; |
| size_t sg_len = 0, len_complete = 0; |
| struct scatterlist *sg; |
| struct page *page; |
| |
| WARN_ON(!irqs_disabled()); |
| |
| for_each_sg(sgl, sg, sg_count, i) { |
| len_complete = sg_len; /* Complete sg-entries */ |
| sg_len += sg->length; |
| if (sg_len > *offset) |
| break; |
| } |
| |
| if (unlikely(i == sg_count)) { |
| printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, " |
| "elements %d\n", |
| __func__, sg_len, *offset, sg_count); |
| WARN_ON(1); |
| return NULL; |
| } |
| |
| /* Offset starting from the beginning of first page in this sg-entry */ |
| *offset = *offset - len_complete + sg->offset; |
| |
| /* Assumption: contiguous pages can be accessed as "page + i" */ |
| page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT)); |
| *offset &= ~PAGE_MASK; |
| |
| /* Bytes in this sg-entry from *offset to the end of the page */ |
| sg_len = PAGE_SIZE - *offset; |
| if (*len > sg_len) |
| *len = sg_len; |
| |
| return kmap_atomic(page); |
| } |
| EXPORT_SYMBOL(scsi_kmap_atomic_sg); |
| |
| /** |
| * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg |
| * @virt: virtual address to be unmapped |
| */ |
| void scsi_kunmap_atomic_sg(void *virt) |
| { |
| kunmap_atomic(virt); |
| } |
| EXPORT_SYMBOL(scsi_kunmap_atomic_sg); |
| |
| void sdev_disable_disk_events(struct scsi_device *sdev) |
| { |
| atomic_inc(&sdev->disk_events_disable_depth); |
| } |
| EXPORT_SYMBOL(sdev_disable_disk_events); |
| |
| void sdev_enable_disk_events(struct scsi_device *sdev) |
| { |
| if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0)) |
| return; |
| atomic_dec(&sdev->disk_events_disable_depth); |
| } |
| EXPORT_SYMBOL(sdev_enable_disk_events); |
| |
| static unsigned char designator_prio(const unsigned char *d) |
| { |
| if (d[1] & 0x30) |
| /* not associated with LUN */ |
| return 0; |
| |
| if (d[3] == 0) |
| /* invalid length */ |
| return 0; |
| |
| /* |
| * Order of preference for lun descriptor: |
| * - SCSI name string |
| * - NAA IEEE Registered Extended |
| * - EUI-64 based 16-byte |
| * - EUI-64 based 12-byte |
| * - NAA IEEE Registered |
| * - NAA IEEE Extended |
| * - EUI-64 based 8-byte |
| * - SCSI name string (truncated) |
| * - T10 Vendor ID |
| * as longer descriptors reduce the likelyhood |
| * of identification clashes. |
| */ |
| |
| switch (d[1] & 0xf) { |
| case 8: |
| /* SCSI name string, variable-length UTF-8 */ |
| return 9; |
| case 3: |
| switch (d[4] >> 4) { |
| case 6: |
| /* NAA registered extended */ |
| return 8; |
| case 5: |
| /* NAA registered */ |
| return 5; |
| case 4: |
| /* NAA extended */ |
| return 4; |
| case 3: |
| /* NAA locally assigned */ |
| return 1; |
| default: |
| break; |
| } |
| break; |
| case 2: |
| switch (d[3]) { |
| case 16: |
| /* EUI64-based, 16 byte */ |
| return 7; |
| case 12: |
| /* EUI64-based, 12 byte */ |
| return 6; |
| case 8: |
| /* EUI64-based, 8 byte */ |
| return 3; |
| default: |
| break; |
| } |
| break; |
| case 1: |
| /* T10 vendor ID */ |
| return 1; |
| default: |
| break; |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * scsi_vpd_lun_id - return a unique device identification |
| * @sdev: SCSI device |
| * @id: buffer for the identification |
| * @id_len: length of the buffer |
| * |
| * Copies a unique device identification into @id based |
| * on the information in the VPD page 0x83 of the device. |
| * The string will be formatted as a SCSI name string. |
| * |
| * Returns the length of the identification or error on failure. |
| * If the identifier is longer than the supplied buffer the actual |
| * identifier length is returned and the buffer is not zero-padded. |
| */ |
| int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len) |
| { |
| u8 cur_id_prio = 0; |
| u8 cur_id_size = 0; |
| const unsigned char *d, *cur_id_str; |
| const struct scsi_vpd *vpd_pg83; |
| int id_size = -EINVAL; |
| |
| rcu_read_lock(); |
| vpd_pg83 = rcu_dereference(sdev->vpd_pg83); |
| if (!vpd_pg83) { |
| rcu_read_unlock(); |
| return -ENXIO; |
| } |
| |
| /* The id string must be at least 20 bytes + terminating NULL byte */ |
| if (id_len < 21) { |
| rcu_read_unlock(); |
| return -EINVAL; |
| } |
| |
| memset(id, 0, id_len); |
| for (d = vpd_pg83->data + 4; |
| d < vpd_pg83->data + vpd_pg83->len; |
| d += d[3] + 4) { |
| u8 prio = designator_prio(d); |
| |
| if (prio == 0 || cur_id_prio > prio) |
| continue; |
| |
| switch (d[1] & 0xf) { |
| case 0x1: |
| /* T10 Vendor ID */ |
| if (cur_id_size > d[3]) |
| break; |
| cur_id_prio = prio; |
| cur_id_size = d[3]; |
| if (cur_id_size + 4 > id_len) |
| cur_id_size = id_len - 4; |
| cur_id_str = d + 4; |
| id_size = snprintf(id, id_len, "t10.%*pE", |
| cur_id_size, cur_id_str); |
| break; |
| case 0x2: |
| /* EUI-64 */ |
| cur_id_prio = prio; |
| cur_id_size = d[3]; |
| cur_id_str = d + 4; |
| switch (cur_id_size) { |
| case 8: |
| id_size = snprintf(id, id_len, |
| "eui.%8phN", |
| cur_id_str); |
| break; |
| case 12: |
| id_size = snprintf(id, id_len, |
| "eui.%12phN", |
| cur_id_str); |
| break; |
| case 16: |
| id_size = snprintf(id, id_len, |
| "eui.%16phN", |
| cur_id_str); |
| break; |
| default: |
| break; |
| } |
| break; |
| case 0x3: |
| /* NAA */ |
| cur_id_prio = prio; |
| cur_id_size = d[3]; |
| cur_id_str = d + 4; |
| switch (cur_id_size) { |
| case 8: |
| id_size = snprintf(id, id_len, |
| "naa.%8phN", |
| cur_id_str); |
| break; |
| case 16: |
| id_size = snprintf(id, id_len, |
| "naa.%16phN", |
| cur_id_str); |
| break; |
| default: |
| break; |
| } |
| break; |
| case 0x8: |
| /* SCSI name string */ |
| if (cur_id_size > d[3]) |
| break; |
| /* Prefer others for truncated descriptor */ |
| if (d[3] > id_len) { |
| prio = 2; |
| if (cur_id_prio > prio) |
| break; |
| } |
| cur_id_prio = prio; |
| cur_id_size = id_size = d[3]; |
| cur_id_str = d + 4; |
| if (cur_id_size >= id_len) |
| cur_id_size = id_len - 1; |
| memcpy(id, cur_id_str, cur_id_size); |
| break; |
| default: |
| break; |
| } |
| } |
| rcu_read_unlock(); |
| |
| return id_size; |
| } |
| EXPORT_SYMBOL(scsi_vpd_lun_id); |
| |
| /* |
| * scsi_vpd_tpg_id - return a target port group identifier |
| * @sdev: SCSI device |
| * |
| * Returns the Target Port Group identifier from the information |
| * froom VPD page 0x83 of the device. |
| * |
| * Returns the identifier or error on failure. |
| */ |
| int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id) |
| { |
| const unsigned char *d; |
| const struct scsi_vpd *vpd_pg83; |
| int group_id = -EAGAIN, rel_port = -1; |
| |
| rcu_read_lock(); |
| vpd_pg83 = rcu_dereference(sdev->vpd_pg83); |
| if (!vpd_pg83) { |
| rcu_read_unlock(); |
| return -ENXIO; |
| } |
| |
| d = vpd_pg83->data + 4; |
| while (d < vpd_pg83->data + vpd_pg83->len) { |
| switch (d[1] & 0xf) { |
| case 0x4: |
| /* Relative target port */ |
| rel_port = get_unaligned_be16(&d[6]); |
| break; |
| case 0x5: |
| /* Target port group */ |
| group_id = get_unaligned_be16(&d[6]); |
|