| /* Xenbus code for blkif backend |
| Copyright (C) 2005 Rusty Russell <rusty@rustcorp.com.au> |
| Copyright (C) 2005 XenSource Ltd |
| |
| 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. |
| |
| */ |
| |
| #include <stdarg.h> |
| #include <linux/module.h> |
| #include <linux/kthread.h> |
| #include <xen/events.h> |
| #include <xen/grant_table.h> |
| #include "common.h" |
| |
| struct backend_info { |
| struct xenbus_device *dev; |
| struct xen_blkif *blkif; |
| struct xenbus_watch backend_watch; |
| unsigned major; |
| unsigned minor; |
| char *mode; |
| }; |
| |
| static struct kmem_cache *xen_blkif_cachep; |
| static void connect(struct backend_info *); |
| static int connect_ring(struct backend_info *); |
| static void backend_changed(struct xenbus_watch *, const char **, |
| unsigned int); |
| |
| struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be) |
| { |
| return be->dev; |
| } |
| |
| static int blkback_name(struct xen_blkif *blkif, char *buf) |
| { |
| char *devpath, *devname; |
| struct xenbus_device *dev = blkif->be->dev; |
| |
| devpath = xenbus_read(XBT_NIL, dev->nodename, "dev", NULL); |
| if (IS_ERR(devpath)) |
| return PTR_ERR(devpath); |
| |
| devname = strstr(devpath, "/dev/"); |
| if (devname != NULL) |
| devname += strlen("/dev/"); |
| else |
| devname = devpath; |
| |
| snprintf(buf, TASK_COMM_LEN, "blkback.%d.%s", blkif->domid, devname); |
| kfree(devpath); |
| |
| return 0; |
| } |
| |
| static void xen_update_blkif_status(struct xen_blkif *blkif) |
| { |
| int err; |
| char name[TASK_COMM_LEN]; |
| |
| /* Not ready to connect? */ |
| if (!blkif->irq || !blkif->vbd.bdev) |
| return; |
| |
| /* Already connected? */ |
| if (blkif->be->dev->state == XenbusStateConnected) |
| return; |
| |
| /* Attempt to connect: exit if we fail to. */ |
| connect(blkif->be); |
| if (blkif->be->dev->state != XenbusStateConnected) |
| return; |
| |
| err = blkback_name(blkif, name); |
| if (err) { |
| xenbus_dev_error(blkif->be->dev, err, "get blkback dev name"); |
| return; |
| } |
| |
| err = filemap_write_and_wait(blkif->vbd.bdev->bd_inode->i_mapping); |
| if (err) { |
| xenbus_dev_error(blkif->be->dev, err, "block flush"); |
| return; |
| } |
| invalidate_inode_pages2(blkif->vbd.bdev->bd_inode->i_mapping); |
| |
| blkif->xenblkd = kthread_run(xen_blkif_schedule, blkif, "%s", name); |
| if (IS_ERR(blkif->xenblkd)) { |
| err = PTR_ERR(blkif->xenblkd); |
| blkif->xenblkd = NULL; |
| xenbus_dev_error(blkif->be->dev, err, "start xenblkd"); |
| } |
| } |
| |
| static struct xen_blkif *xen_blkif_alloc(domid_t domid) |
| { |
| struct xen_blkif *blkif; |
| |
| blkif = kmem_cache_zalloc(xen_blkif_cachep, GFP_KERNEL); |
| if (!blkif) |
| return ERR_PTR(-ENOMEM); |
| |
| blkif->domid = domid; |
| spin_lock_init(&blkif->blk_ring_lock); |
| atomic_set(&blkif->refcnt, 1); |
| init_waitqueue_head(&blkif->wq); |
| init_completion(&blkif->drain_complete); |
| atomic_set(&blkif->drain, 0); |
| blkif->st_print = jiffies; |
| init_waitqueue_head(&blkif->waiting_to_free); |
| blkif->persistent_gnts.rb_node = NULL; |
| |
| return blkif; |
| } |
| |
| static int xen_blkif_map(struct xen_blkif *blkif, unsigned long shared_page, |
| unsigned int evtchn) |
| { |
| int err; |
| |
| /* Already connected through? */ |
| if (blkif->irq) |
| return 0; |
| |
| err = xenbus_map_ring_valloc(blkif->be->dev, shared_page, &blkif->blk_ring); |
| if (err < 0) |
| return err; |
| |
| switch (blkif->blk_protocol) { |
| case BLKIF_PROTOCOL_NATIVE: |
| { |
| struct blkif_sring *sring; |
| sring = (struct blkif_sring *)blkif->blk_ring; |
| BACK_RING_INIT(&blkif->blk_rings.native, sring, PAGE_SIZE); |
| break; |
| } |
| case BLKIF_PROTOCOL_X86_32: |
| { |
| struct blkif_x86_32_sring *sring_x86_32; |
| sring_x86_32 = (struct blkif_x86_32_sring *)blkif->blk_ring; |
| BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, PAGE_SIZE); |
| break; |
| } |
| case BLKIF_PROTOCOL_X86_64: |
| { |
| struct blkif_x86_64_sring *sring_x86_64; |
| sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring; |
| BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, PAGE_SIZE); |
| break; |
| } |
| default: |
| BUG(); |
| } |
| |
| err = bind_interdomain_evtchn_to_irqhandler(blkif->domid, evtchn, |
| xen_blkif_be_int, 0, |
| "blkif-backend", blkif); |
| if (err < 0) { |
| xenbus_unmap_ring_vfree(blkif->be->dev, blkif->blk_ring); |
| blkif->blk_rings.common.sring = NULL; |
| return err; |
| } |
| blkif->irq = err; |
| |
| return 0; |
| } |
| |
| static void xen_blkif_disconnect(struct xen_blkif *blkif) |
| { |
| if (blkif->xenblkd) { |
| kthread_stop(blkif->xenblkd); |
| blkif->xenblkd = NULL; |
| } |
| |
| atomic_dec(&blkif->refcnt); |
| wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0); |
| atomic_inc(&blkif->refcnt); |
| |
| if (blkif->irq) { |
| unbind_from_irqhandler(blkif->irq, blkif); |
| blkif->irq = 0; |
| } |
| |
| if (blkif->blk_rings.common.sring) { |
| xenbus_unmap_ring_vfree(blkif->be->dev, blkif->blk_ring); |
| blkif->blk_rings.common.sring = NULL; |
| } |
| } |
| |
| static void xen_blkif_free(struct xen_blkif *blkif) |
| { |
| if (!atomic_dec_and_test(&blkif->refcnt)) |
| BUG(); |
| kmem_cache_free(xen_blkif_cachep, blkif); |
| } |
| |
| int __init xen_blkif_interface_init(void) |
| { |
| xen_blkif_cachep = kmem_cache_create("blkif_cache", |
| sizeof(struct xen_blkif), |
| 0, 0, NULL); |
| if (!xen_blkif_cachep) |
| return -ENOMEM; |
| |
| return 0; |
| } |
| |
| /* |
| * sysfs interface for VBD I/O requests |
| */ |
| |
| #define VBD_SHOW(name, format, args...) \ |
| static ssize_t show_##name(struct device *_dev, \ |
| struct device_attribute *attr, \ |
| char *buf) \ |
| { \ |
| struct xenbus_device *dev = to_xenbus_device(_dev); \ |
| struct backend_info *be = dev_get_drvdata(&dev->dev); \ |
| \ |
| return sprintf(buf, format, ##args); \ |
| } \ |
| static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL) |
| |
| VBD_SHOW(oo_req, "%llu\n", be->blkif->st_oo_req); |
| VBD_SHOW(rd_req, "%llu\n", be->blkif->st_rd_req); |
| VBD_SHOW(wr_req, "%llu\n", be->blkif->st_wr_req); |
| VBD_SHOW(f_req, "%llu\n", be->blkif->st_f_req); |
| VBD_SHOW(ds_req, "%llu\n", be->blkif->st_ds_req); |
| VBD_SHOW(rd_sect, "%llu\n", be->blkif->st_rd_sect); |
| VBD_SHOW(wr_sect, "%llu\n", be->blkif->st_wr_sect); |
| |
| static struct attribute *xen_vbdstat_attrs[] = { |
| &dev_attr_oo_req.attr, |
| &dev_attr_rd_req.attr, |
| &dev_attr_wr_req.attr, |
| &dev_attr_f_req.attr, |
| &dev_attr_ds_req.attr, |
| &dev_attr_rd_sect.attr, |
| &dev_attr_wr_sect.attr, |
| NULL |
| }; |
| |
| static struct attribute_group xen_vbdstat_group = { |
| .name = "statistics", |
| .attrs = xen_vbdstat_attrs, |
| }; |
| |
| VBD_SHOW(physical_device, "%x:%x\n", be->major, be->minor); |
| VBD_SHOW(mode, "%s\n", be->mode); |
| |
| static int xenvbd_sysfs_addif(struct xenbus_device *dev) |
| { |
| int error; |
| |
| error = device_create_file(&dev->dev, &dev_attr_physical_device); |
| if (error) |
| goto fail1; |
| |
| error = device_create_file(&dev->dev, &dev_attr_mode); |
| if (error) |
| goto fail2; |
| |
| error = sysfs_create_group(&dev->dev.kobj, &xen_vbdstat_group); |
| if (error) |
| goto fail3; |
| |
| return 0; |
| |
| fail3: sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group); |
| fail2: device_remove_file(&dev->dev, &dev_attr_mode); |
| fail1: device_remove_file(&dev->dev, &dev_attr_physical_device); |
| return error; |
| } |
| |
| static void xenvbd_sysfs_delif(struct xenbus_device *dev) |
| { |
| sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group); |
| device_remove_file(&dev->dev, &dev_attr_mode); |
| device_remove_file(&dev->dev, &dev_attr_physical_device); |
| } |
| |
| |
| static void xen_vbd_free(struct xen_vbd *vbd) |
| { |
| if (vbd->bdev) |
| blkdev_put(vbd->bdev, vbd->readonly ? FMODE_READ : FMODE_WRITE); |
| vbd->bdev = NULL; |
| } |
| |
| static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle, |
| unsigned major, unsigned minor, int readonly, |
| int cdrom) |
| { |
| struct xen_vbd *vbd; |
| struct block_device *bdev; |
| struct request_queue *q; |
| |
| vbd = &blkif->vbd; |
| vbd->handle = handle; |
| vbd->readonly = readonly; |
| vbd->type = 0; |
| |
| vbd->pdevice = MKDEV(major, minor); |
| |
| bdev = blkdev_get_by_dev(vbd->pdevice, vbd->readonly ? |
| FMODE_READ : FMODE_WRITE, NULL); |
| |
| if (IS_ERR(bdev)) { |
| DPRINTK("xen_vbd_create: device %08x could not be opened.\n", |
| vbd->pdevice); |
| return -ENOENT; |
| } |
| |
| vbd->bdev = bdev; |
| if (vbd->bdev->bd_disk == NULL) { |
| DPRINTK("xen_vbd_create: device %08x doesn't exist.\n", |
| vbd->pdevice); |
| xen_vbd_free(vbd); |
| return -ENOENT; |
| } |
| vbd->size = vbd_sz(vbd); |
| |
| if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom) |
| vbd->type |= VDISK_CDROM; |
| if (vbd->bdev->bd_disk->flags & GENHD_FL_REMOVABLE) |
| vbd->type |= VDISK_REMOVABLE; |
| |
| q = bdev_get_queue(bdev); |
| if (q && q->flush_flags) |
| vbd->flush_support = true; |
| |
| if (q && blk_queue_secdiscard(q)) |
| vbd->discard_secure = true; |
| |
| DPRINTK("Successful creation of handle=%04x (dom=%u)\n", |
| handle, blkif->domid); |
| return 0; |
| } |
| static int xen_blkbk_remove(struct xenbus_device *dev) |
| { |
| struct backend_info *be = dev_get_drvdata(&dev->dev); |
| |
| DPRINTK(""); |
| |
| if (be->major || be->minor) |
| xenvbd_sysfs_delif(dev); |
| |
| if (be->backend_watch.node) { |
| unregister_xenbus_watch(&be->backend_watch); |
| kfree(be->backend_watch.node); |
| be->backend_watch.node = NULL; |
| } |
| |
| if (be->blkif) { |
| xen_blkif_disconnect(be->blkif); |
| xen_vbd_free(&be->blkif->vbd); |
| xen_blkif_free(be->blkif); |
| be->blkif = NULL; |
| } |
| |
| kfree(be->mode); |
| kfree(be); |
| dev_set_drvdata(&dev->dev, NULL); |
| return 0; |
| } |
| |
| int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt, |
| struct backend_info *be, int state) |
| { |
| struct xenbus_device *dev = be->dev; |
| int err; |
| |
| err = xenbus_printf(xbt, dev->nodename, "feature-flush-cache", |
| "%d", state); |
| if (err) |
| dev_warn(&dev->dev, "writing feature-flush-cache (%d)", err); |
| |
| return err; |
| } |
| |
| static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info *be) |
| { |
| struct xenbus_device *dev = be->dev; |
| struct xen_blkif *blkif = be->blkif; |
| int err; |
| int state = 0; |
| struct block_device *bdev = be->blkif->vbd.bdev; |
| struct request_queue *q = bdev_get_queue(bdev); |
| |
| if (blk_queue_discard(q)) { |
| err = xenbus_printf(xbt, dev->nodename, |
| "discard-granularity", "%u", |
| q->limits.discard_granularity); |
| if (err) { |
| dev_warn(&dev->dev, "writing discard-granularity (%d)", err); |
| return; |
| } |
| err = xenbus_printf(xbt, dev->nodename, |
| "discard-alignment", "%u", |
| q->limits.discard_alignment); |
| if (err) { |
| dev_warn(&dev->dev, "writing discard-alignment (%d)", err); |
| return; |
| } |
| state = 1; |
| /* Optional. */ |
| err = xenbus_printf(xbt, dev->nodename, |
| "discard-secure", "%d", |
| blkif->vbd.discard_secure); |
| if (err) { |
| dev_warn(&dev->dev, "writing discard-secure (%d)", err); |
| return; |
| } |
| } |
| err = xenbus_printf(xbt, dev->nodename, "feature-discard", |
| "%d", state); |
| if (err) |
| dev_warn(&dev->dev, "writing feature-discard (%d)", err); |
| } |
| int xen_blkbk_barrier(struct xenbus_transaction xbt, |
| struct backend_info *be, int state) |
| { |
| struct xenbus_device *dev = be->dev; |
| int err; |
| |
| err = xenbus_printf(xbt, dev->nodename, "feature-barrier", |
| "%d", state); |
| if (err) |
| dev_warn(&dev->dev, "writing feature-barrier (%d)", err); |
| |
| return err; |
| } |
| |
| /* |
| * Entry point to this code when a new device is created. Allocate the basic |
| * structures, and watch the store waiting for the hotplug scripts to tell us |
| * the device's physical major and minor numbers. Switch to InitWait. |
| */ |
| static int xen_blkbk_probe(struct xenbus_device *dev, |
| const struct xenbus_device_id *id) |
| { |
| int err; |
| struct backend_info *be = kzalloc(sizeof(struct backend_info), |
| GFP_KERNEL); |
| if (!be) { |
| xenbus_dev_fatal(dev, -ENOMEM, |
| "allocating backend structure"); |
| return -ENOMEM; |
| } |
| be->dev = dev; |
| dev_set_drvdata(&dev->dev, be); |
| |
| be->blkif = xen_blkif_alloc(dev->otherend_id); |
| if (IS_ERR(be->blkif)) { |
| err = PTR_ERR(be->blkif); |
| be->blkif = NULL; |
| xenbus_dev_fatal(dev, err, "creating block interface"); |
| goto fail; |
| } |
| |
| /* setup back pointer */ |
| be->blkif->be = be; |
| |
| err = xenbus_watch_pathfmt(dev, &be->backend_watch, backend_changed, |
| "%s/%s", dev->nodename, "physical-device"); |
| if (err) |
| goto fail; |
| |
| err = xenbus_switch_state(dev, XenbusStateInitWait); |
| if (err) |
| goto fail; |
| |
| return 0; |
| |
| fail: |
| DPRINTK("failed"); |
| xen_blkbk_remove(dev); |
| return err; |
| } |
| |
| |
| /* |
| * Callback received when the hotplug scripts have placed the physical-device |
| * node. Read it and the mode node, and create a vbd. If the frontend is |
| * ready, connect. |
| */ |
| static void backend_changed(struct xenbus_watch *watch, |
| const char **vec, unsigned int len) |
| { |
| int err; |
| unsigned major; |
| unsigned minor; |
| struct backend_info *be |
| = container_of(watch, struct backend_info, backend_watch); |
| struct xenbus_device *dev = be->dev; |
| int cdrom = 0; |
| unsigned long handle; |
| char *device_type; |
| |
| DPRINTK(""); |
| |
| err = xenbus_scanf(XBT_NIL, dev->nodename, "physical-device", "%x:%x", |
| &major, &minor); |
| if (XENBUS_EXIST_ERR(err)) { |
| /* |
| * Since this watch will fire once immediately after it is |
| * registered, we expect this. Ignore it, and wait for the |
| * hotplug scripts. |
| */ |
| return; |
| } |
| if (err != 2) { |
| xenbus_dev_fatal(dev, err, "reading physical-device"); |
| return; |
| } |
| |
| if (be->major | be->minor) { |
| if (be->major != major || be->minor != minor) |
| pr_warn(DRV_PFX "changing physical device (from %x:%x to %x:%x) not supported.\n", |
| be->major, be->minor, major, minor); |
| return; |
| } |
| |
| be->mode = xenbus_read(XBT_NIL, dev->nodename, "mode", NULL); |
| if (IS_ERR(be->mode)) { |
| err = PTR_ERR(be->mode); |
| be->mode = NULL; |
| xenbus_dev_fatal(dev, err, "reading mode"); |
| return; |
| } |
| |
| device_type = xenbus_read(XBT_NIL, dev->otherend, "device-type", NULL); |
| if (!IS_ERR(device_type)) { |
| cdrom = strcmp(device_type, "cdrom") == 0; |
| kfree(device_type); |
| } |
| |
| /* Front end dir is a number, which is used as the handle. */ |
| err = strict_strtoul(strrchr(dev->otherend, '/') + 1, 0, &handle); |
| if (err) |
| return; |
| |
| be->major = major; |
| be->minor = minor; |
| |
| err = xen_vbd_create(be->blkif, handle, major, minor, |
| !strchr(be->mode, 'w'), cdrom); |
| |
| if (err) |
| xenbus_dev_fatal(dev, err, "creating vbd structure"); |
| else { |
| err = xenvbd_sysfs_addif(dev); |
| if (err) { |
| xen_vbd_free(&be->blkif->vbd); |
| xenbus_dev_fatal(dev, err, "creating sysfs entries"); |
| } |
| } |
| |
| if (err) { |
| kfree(be->mode); |
| be->mode = NULL; |
| be->major = 0; |
| be->minor = 0; |
| } else { |
| /* We're potentially connected now */ |
| xen_update_blkif_status(be->blkif); |
| } |
| } |
| |
| |
| /* |
| * Callback received when the frontend's state changes. |
| */ |
| static void frontend_changed(struct xenbus_device *dev, |
| enum xenbus_state frontend_state) |
| { |
| struct backend_info *be = dev_get_drvdata(&dev->dev); |
| int err; |
| |
| DPRINTK("%s", xenbus_strstate(frontend_state)); |
| |
| switch (frontend_state) { |
| case XenbusStateInitialising: |
| if (dev->state == XenbusStateClosed) { |
| pr_info(DRV_PFX "%s: prepare for reconnect\n", |
| dev->nodename); |
| xenbus_switch_state(dev, XenbusStateInitWait); |
| } |
| break; |
| |
| case XenbusStateInitialised: |
| case XenbusStateConnected: |
| /* |
| * Ensure we connect even when two watches fire in |
| * close succession and we miss the intermediate value |
| * of frontend_state. |
| */ |
| if (dev->state == XenbusStateConnected) |
| break; |
| |
| /* |
| * Enforce precondition before potential leak point. |
| * xen_blkif_disconnect() is idempotent. |
| */ |
| xen_blkif_disconnect(be->blkif); |
| |
| err = connect_ring(be); |
| if (err) |
| break; |
| xen_update_blkif_status(be->blkif); |
| break; |
| |
| case XenbusStateClosing: |
| xenbus_switch_state(dev, XenbusStateClosing); |
| break; |
| |
| case XenbusStateClosed: |
| xen_blkif_disconnect(be->blkif); |
| xenbus_switch_state(dev, XenbusStateClosed); |
| if (xenbus_dev_is_online(dev)) |
| break; |
| /* fall through if not online */ |
| case XenbusStateUnknown: |
| /* implies xen_blkif_disconnect() via xen_blkbk_remove() */ |
| device_unregister(&dev->dev); |
| break; |
| |
| default: |
| xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend", |
| frontend_state); |
| break; |
| } |
| } |
| |
| |
| /* ** Connection ** */ |
| |
| |
| /* |
| * Write the physical details regarding the block device to the store, and |
| * switch to Connected state. |
| */ |
| static void connect(struct backend_info *be) |
| { |
| struct xenbus_transaction xbt; |
| int err; |
| struct xenbus_device *dev = be->dev; |
| |
| DPRINTK("%s", dev->otherend); |
| |
| /* Supply the information about the device the frontend needs */ |
| again: |
| err = xenbus_transaction_start(&xbt); |
| if (err) { |
| xenbus_dev_fatal(dev, err, "starting transaction"); |
| return; |
| } |
| |
| /* If we can't advertise it is OK. */ |
| xen_blkbk_flush_diskcache(xbt, be, be->blkif->vbd.flush_support); |
| |
| xen_blkbk_discard(xbt, be); |
| |
| xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support); |
| |
| err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", 1); |
| if (err) { |
| xenbus_dev_fatal(dev, err, "writing %s/feature-persistent", |
| dev->nodename); |
| goto abort; |
| } |
| |
| err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu", |
| (unsigned long long)vbd_sz(&be->blkif->vbd)); |
| if (err) { |
| xenbus_dev_fatal(dev, err, "writing %s/sectors", |
| dev->nodename); |
| goto abort; |
| } |
| |
| /* FIXME: use a typename instead */ |
| err = xenbus_printf(xbt, dev->nodename, "info", "%u", |
| be->blkif->vbd.type | |
| (be->blkif->vbd.readonly ? VDISK_READONLY : 0)); |
| if (err) { |
| xenbus_dev_fatal(dev, err, "writing %s/info", |
| dev->nodename); |
| goto abort; |
| } |
| err = xenbus_printf(xbt, dev->nodename, "sector-size", "%lu", |
| (unsigned long) |
| bdev_logical_block_size(be->blkif->vbd.bdev)); |
| if (err) { |
| xenbus_dev_fatal(dev, err, "writing %s/sector-size", |
| dev->nodename); |
| goto abort; |
| } |
| |
| err = xenbus_transaction_end(xbt, 0); |
| if (err == -EAGAIN) |
| goto again; |
| if (err) |
| xenbus_dev_fatal(dev, err, "ending transaction"); |
| |
| err = xenbus_switch_state(dev, XenbusStateConnected); |
| if (err) |
| xenbus_dev_fatal(dev, err, "%s: switching to Connected state", |
| dev->nodename); |
| |
| return; |
| abort: |
| xenbus_transaction_end(xbt, 1); |
| } |
| |
| |
| static int connect_ring(struct backend_info *be) |
| { |
| struct xenbus_device *dev = be->dev; |
| unsigned long ring_ref; |
| unsigned int evtchn; |
| unsigned int pers_grants; |
| char protocol[64] = ""; |
| int err; |
| |
| DPRINTK("%s", dev->otherend); |
| |
| err = xenbus_gather(XBT_NIL, dev->otherend, "ring-ref", "%lu", |
| &ring_ref, "event-channel", "%u", &evtchn, NULL); |
| if (err) { |
| xenbus_dev_fatal(dev, err, |
| "reading %s/ring-ref and event-channel", |
| dev->otherend); |
| return err; |
| } |
| |
| be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE; |
| err = xenbus_gather(XBT_NIL, dev->otherend, "protocol", |
| "%63s", protocol, NULL); |
| if (err) |
| strcpy(protocol, "unspecified, assuming native"); |
| else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE)) |
| be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE; |
| else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32)) |
| be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_32; |
| else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64)) |
| be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_64; |
| else { |
| xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol); |
| return -1; |
| } |
| err = xenbus_gather(XBT_NIL, dev->otherend, |
| "feature-persistent", "%u", |
| &pers_grants, NULL); |
| if (err) |
| pers_grants = 0; |
| |
| be->blkif->vbd.feature_gnt_persistent = pers_grants; |
| be->blkif->vbd.overflow_max_grants = 0; |
| |
| pr_info(DRV_PFX "ring-ref %ld, event-channel %d, protocol %d (%s) %s\n", |
| ring_ref, evtchn, be->blkif->blk_protocol, protocol, |
| pers_grants ? "persistent grants" : ""); |
| |
| /* Map the shared frame, irq etc. */ |
| err = xen_blkif_map(be->blkif, ring_ref, evtchn); |
| if (err) { |
| xenbus_dev_fatal(dev, err, "mapping ring-ref %lu port %u", |
| ring_ref, evtchn); |
| return err; |
| } |
| |
| return 0; |
| } |
| |
| |
| /* ** Driver Registration ** */ |
| |
| |
| static const struct xenbus_device_id xen_blkbk_ids[] = { |
| { "vbd" }, |
| { "" } |
| }; |
| |
| |
| static DEFINE_XENBUS_DRIVER(xen_blkbk, , |
| .probe = xen_blkbk_probe, |
| .remove = xen_blkbk_remove, |
| .otherend_changed = frontend_changed |
| ); |
| |
| |
| int xen_blkif_xenbus_init(void) |
| { |
| return xenbus_register_backend(&xen_blkbk_driver); |
| } |