| /* |
| * BSG helper library |
| * |
| * Copyright (C) 2008 James Smart, Emulex Corporation |
| * Copyright (C) 2011 Red Hat, Inc. All rights reserved. |
| * Copyright (C) 2011 Mike Christie |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| * |
| */ |
| #include <linux/slab.h> |
| #include <linux/blk-mq.h> |
| #include <linux/delay.h> |
| #include <linux/scatterlist.h> |
| #include <linux/bsg-lib.h> |
| #include <linux/export.h> |
| #include <scsi/scsi_cmnd.h> |
| #include <scsi/sg.h> |
| |
| #define uptr64(val) ((void __user *)(uintptr_t)(val)) |
| |
| static int bsg_transport_check_proto(struct sg_io_v4 *hdr) |
| { |
| if (hdr->protocol != BSG_PROTOCOL_SCSI || |
| hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_TRANSPORT) |
| return -EINVAL; |
| if (!capable(CAP_SYS_RAWIO)) |
| return -EPERM; |
| return 0; |
| } |
| |
| static int bsg_transport_fill_hdr(struct request *rq, struct sg_io_v4 *hdr, |
| fmode_t mode) |
| { |
| struct bsg_job *job = blk_mq_rq_to_pdu(rq); |
| |
| job->request_len = hdr->request_len; |
| job->request = memdup_user(uptr64(hdr->request), hdr->request_len); |
| |
| return PTR_ERR_OR_ZERO(job->request); |
| } |
| |
| static int bsg_transport_complete_rq(struct request *rq, struct sg_io_v4 *hdr) |
| { |
| struct bsg_job *job = blk_mq_rq_to_pdu(rq); |
| int ret = 0; |
| |
| /* |
| * The assignments below don't make much sense, but are kept for |
| * bug by bug backwards compatibility: |
| */ |
| hdr->device_status = job->result & 0xff; |
| hdr->transport_status = host_byte(job->result); |
| hdr->driver_status = driver_byte(job->result); |
| hdr->info = 0; |
| if (hdr->device_status || hdr->transport_status || hdr->driver_status) |
| hdr->info |= SG_INFO_CHECK; |
| hdr->response_len = 0; |
| |
| if (job->result < 0) { |
| /* we're only returning the result field in the reply */ |
| job->reply_len = sizeof(u32); |
| ret = job->result; |
| } |
| |
| if (job->reply_len && hdr->response) { |
| int len = min(hdr->max_response_len, job->reply_len); |
| |
| if (copy_to_user(uptr64(hdr->response), job->reply, len)) |
| ret = -EFAULT; |
| else |
| hdr->response_len = len; |
| } |
| |
| /* we assume all request payload was transferred, residual == 0 */ |
| hdr->dout_resid = 0; |
| |
| if (rq->next_rq) { |
| unsigned int rsp_len = job->reply_payload.payload_len; |
| |
| if (WARN_ON(job->reply_payload_rcv_len > rsp_len)) |
| hdr->din_resid = 0; |
| else |
| hdr->din_resid = rsp_len - job->reply_payload_rcv_len; |
| } else { |
| hdr->din_resid = 0; |
| } |
| |
| return ret; |
| } |
| |
| static void bsg_transport_free_rq(struct request *rq) |
| { |
| struct bsg_job *job = blk_mq_rq_to_pdu(rq); |
| |
| kfree(job->request); |
| } |
| |
| static const struct bsg_ops bsg_transport_ops = { |
| .check_proto = bsg_transport_check_proto, |
| .fill_hdr = bsg_transport_fill_hdr, |
| .complete_rq = bsg_transport_complete_rq, |
| .free_rq = bsg_transport_free_rq, |
| }; |
| |
| /** |
| * bsg_teardown_job - routine to teardown a bsg job |
| * @kref: kref inside bsg_job that is to be torn down |
| */ |
| static void bsg_teardown_job(struct kref *kref) |
| { |
| struct bsg_job *job = container_of(kref, struct bsg_job, kref); |
| struct request *rq = blk_mq_rq_from_pdu(job); |
| |
| put_device(job->dev); /* release reference for the request */ |
| |
| kfree(job->request_payload.sg_list); |
| kfree(job->reply_payload.sg_list); |
| |
| blk_mq_end_request(rq, BLK_STS_OK); |
| } |
| |
| void bsg_job_put(struct bsg_job *job) |
| { |
| kref_put(&job->kref, bsg_teardown_job); |
| } |
| EXPORT_SYMBOL_GPL(bsg_job_put); |
| |
| int bsg_job_get(struct bsg_job *job) |
| { |
| return kref_get_unless_zero(&job->kref); |
| } |
| EXPORT_SYMBOL_GPL(bsg_job_get); |
| |
| /** |
| * bsg_job_done - completion routine for bsg requests |
| * @job: bsg_job that is complete |
| * @result: job reply result |
| * @reply_payload_rcv_len: length of payload recvd |
| * |
| * The LLD should call this when the bsg job has completed. |
| */ |
| void bsg_job_done(struct bsg_job *job, int result, |
| unsigned int reply_payload_rcv_len) |
| { |
| job->result = result; |
| job->reply_payload_rcv_len = reply_payload_rcv_len; |
| blk_mq_complete_request(blk_mq_rq_from_pdu(job)); |
| } |
| EXPORT_SYMBOL_GPL(bsg_job_done); |
| |
| /** |
| * bsg_complete - softirq done routine for destroying the bsg requests |
| * @rq: BSG request that holds the job to be destroyed |
| */ |
| static void bsg_complete(struct request *rq) |
| { |
| struct bsg_job *job = blk_mq_rq_to_pdu(rq); |
| |
| bsg_job_put(job); |
| } |
| |
| static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req) |
| { |
| size_t sz = (sizeof(struct scatterlist) * req->nr_phys_segments); |
| |
| BUG_ON(!req->nr_phys_segments); |
| |
| buf->sg_list = kzalloc(sz, GFP_KERNEL); |
| if (!buf->sg_list) |
| return -ENOMEM; |
| sg_init_table(buf->sg_list, req->nr_phys_segments); |
| buf->sg_cnt = blk_rq_map_sg(req->q, req, buf->sg_list); |
| buf->payload_len = blk_rq_bytes(req); |
| return 0; |
| } |
| |
| /** |
| * bsg_prepare_job - create the bsg_job structure for the bsg request |
| * @dev: device that is being sent the bsg request |
| * @req: BSG request that needs a job structure |
| */ |
| static bool bsg_prepare_job(struct device *dev, struct request *req) |
| { |
| struct request *rsp = req->next_rq; |
| struct bsg_job *job = blk_mq_rq_to_pdu(req); |
| int ret; |
| |
| job->timeout = req->timeout; |
| |
| if (req->bio) { |
| ret = bsg_map_buffer(&job->request_payload, req); |
| if (ret) |
| goto failjob_rls_job; |
| } |
| if (rsp && rsp->bio) { |
| ret = bsg_map_buffer(&job->reply_payload, rsp); |
| if (ret) |
| goto failjob_rls_rqst_payload; |
| } |
| job->dev = dev; |
| /* take a reference for the request */ |
| get_device(job->dev); |
| kref_init(&job->kref); |
| return true; |
| |
| failjob_rls_rqst_payload: |
| kfree(job->request_payload.sg_list); |
| failjob_rls_job: |
| job->result = -ENOMEM; |
| return false; |
| } |
| |
| /** |
| * bsg_queue_rq - generic handler for bsg requests |
| * @hctx: hardware queue |
| * @bd: queue data |
| * |
| * On error the create_bsg_job function should return a -Exyz error value |
| * that will be set to ->result. |
| * |
| * Drivers/subsys should pass this to the queue init function. |
| */ |
| static blk_status_t bsg_queue_rq(struct blk_mq_hw_ctx *hctx, |
| const struct blk_mq_queue_data *bd) |
| { |
| struct request_queue *q = hctx->queue; |
| struct device *dev = q->queuedata; |
| struct request *req = bd->rq; |
| int ret; |
| |
| blk_mq_start_request(req); |
| |
| if (!get_device(dev)) |
| return BLK_STS_IOERR; |
| |
| if (!bsg_prepare_job(dev, req)) |
| return BLK_STS_IOERR; |
| |
| ret = q->bsg_job_fn(blk_mq_rq_to_pdu(req)); |
| if (ret) |
| return BLK_STS_IOERR; |
| |
| put_device(dev); |
| return BLK_STS_OK; |
| } |
| |
| /* called right after the request is allocated for the request_queue */ |
| static int bsg_init_rq(struct blk_mq_tag_set *set, struct request *req, |
| unsigned int hctx_idx, unsigned int numa_node) |
| { |
| struct bsg_job *job = blk_mq_rq_to_pdu(req); |
| |
| job->reply = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_KERNEL); |
| if (!job->reply) |
| return -ENOMEM; |
| return 0; |
| } |
| |
| /* called right before the request is given to the request_queue user */ |
| static void bsg_initialize_rq(struct request *req) |
| { |
| struct bsg_job *job = blk_mq_rq_to_pdu(req); |
| void *reply = job->reply; |
| |
| memset(job, 0, sizeof(*job)); |
| job->reply = reply; |
| job->reply_len = SCSI_SENSE_BUFFERSIZE; |
| job->dd_data = job + 1; |
| } |
| |
| static void bsg_exit_rq(struct blk_mq_tag_set *set, struct request *req, |
| unsigned int hctx_idx) |
| { |
| struct bsg_job *job = blk_mq_rq_to_pdu(req); |
| |
| kfree(job->reply); |
| } |
| |
| void bsg_remove_queue(struct request_queue *q) |
| { |
| if (q) { |
| struct blk_mq_tag_set *set = q->tag_set; |
| |
| bsg_unregister_queue(q); |
| blk_cleanup_queue(q); |
| blk_mq_free_tag_set(set); |
| kfree(set); |
| } |
| } |
| EXPORT_SYMBOL_GPL(bsg_remove_queue); |
| |
| static enum blk_eh_timer_return bsg_timeout(struct request *rq, bool reserved) |
| { |
| enum blk_eh_timer_return ret = BLK_EH_DONE; |
| struct request_queue *q = rq->q; |
| |
| if (q->rq_timed_out_fn) |
| ret = q->rq_timed_out_fn(rq); |
| |
| return ret; |
| } |
| |
| static const struct blk_mq_ops bsg_mq_ops = { |
| .queue_rq = bsg_queue_rq, |
| .init_request = bsg_init_rq, |
| .exit_request = bsg_exit_rq, |
| .initialize_rq_fn = bsg_initialize_rq, |
| .complete = bsg_complete, |
| .timeout = bsg_timeout, |
| }; |
| |
| /** |
| * bsg_setup_queue - Create and add the bsg hooks so we can receive requests |
| * @dev: device to attach bsg device to |
| * @name: device to give bsg device |
| * @job_fn: bsg job handler |
| * @dd_job_size: size of LLD data needed for each job |
| */ |
| struct request_queue *bsg_setup_queue(struct device *dev, const char *name, |
| bsg_job_fn *job_fn, rq_timed_out_fn *timeout, int dd_job_size) |
| { |
| struct blk_mq_tag_set *set; |
| struct request_queue *q; |
| int ret = -ENOMEM; |
| |
| set = kzalloc(sizeof(*set), GFP_KERNEL); |
| if (!set) |
| return ERR_PTR(-ENOMEM); |
| |
| set->ops = &bsg_mq_ops, |
| set->nr_hw_queues = 1; |
| set->queue_depth = 128; |
| set->numa_node = NUMA_NO_NODE; |
| set->cmd_size = sizeof(struct bsg_job) + dd_job_size; |
| set->flags = BLK_MQ_F_NO_SCHED | BLK_MQ_F_BLOCKING; |
| if (blk_mq_alloc_tag_set(set)) |
| goto out_tag_set; |
| |
| q = blk_mq_init_queue(set); |
| if (IS_ERR(q)) { |
| ret = PTR_ERR(q); |
| goto out_queue; |
| } |
| |
| q->queuedata = dev; |
| q->bsg_job_fn = job_fn; |
| blk_queue_flag_set(QUEUE_FLAG_BIDI, q); |
| blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT); |
| q->rq_timed_out_fn = timeout; |
| |
| ret = bsg_register_queue(q, dev, name, &bsg_transport_ops); |
| if (ret) { |
| printk(KERN_ERR "%s: bsg interface failed to " |
| "initialize - register queue\n", dev->kobj.name); |
| goto out_cleanup_queue; |
| } |
| |
| return q; |
| out_cleanup_queue: |
| blk_cleanup_queue(q); |
| out_queue: |
| blk_mq_free_tag_set(set); |
| out_tag_set: |
| kfree(set); |
| return ERR_PTR(ret); |
| } |
| EXPORT_SYMBOL_GPL(bsg_setup_queue); |