/* 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); static void xen_blkif_free(struct xen_blkif *blkif); static void xen_vbd_free(struct xen_vbd *vbd); struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be) { return be->dev; } /* * The last request could free the device from softirq context and * xen_blkif_free() can sleep. */ static void xen_blkif_deferred_free(struct work_struct *work) { struct xen_blkif *blkif; blkif = container_of(work, struct xen_blkif, free_work); xen_blkif_free(blkif); } 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"); return; } } static struct xen_blkif *xen_blkif_alloc(domid_t domid) { struct xen_blkif *blkif; struct pending_req *req, *n; int i, j; BUILD_BUG_ON(MAX_INDIRECT_PAGES > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST); 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; blkif->persistent_gnts.rb_node = NULL; spin_lock_init(&blkif->free_pages_lock); INIT_LIST_HEAD(&blkif->free_pages); INIT_LIST_HEAD(&blkif->persistent_purge_list); blkif->free_pages_num = 0; atomic_set(&blkif->persistent_gnt_in_use, 0); atomic_set(&blkif->inflight, 0); INIT_WORK(&blkif->persistent_purge_work, xen_blkbk_unmap_purged_grants); INIT_LIST_HEAD(&blkif->pending_free); INIT_WORK(&blkif->free_work, xen_blkif_deferred_free); for (i = 0; i < XEN_BLKIF_REQS; i++) { req = kzalloc(sizeof(*req), GFP_KERNEL); if (!req) goto fail; list_add_tail(&req->free_list, &blkif->pending_free); for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) { req->segments[j] = kzalloc(sizeof(*req->segments[0]), GFP_KERNEL); if (!req->segments[j]) goto fail; } for (j = 0; j < MAX_INDIRECT_PAGES; j++) { req->indirect_pages[j] = kzalloc(sizeof(*req->indirect_pages[0]), GFP_KERNEL); if (!req->indirect_pages[j]) goto fail; } } spin_lock_init(&blkif->pending_free_lock); init_waitqueue_head(&blkif->pending_free_wq); init_waitqueue_head(&blkif->shutdown_wq); return blkif; fail: list_for_each_entry_safe(req, n, &blkif->pending_free, free_list) { list_del(&req->free_list); for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) { if (!req->segments[j]) break; kfree(req->segments[j]); } for (j = 0; j < MAX_INDIRECT_PAGES; j++) { if (!req->indirect_pages[j]) break; kfree(req->indirect_pages[j]); } kfree(req); } kmem_cache_free(xen_blkif_cachep, blkif); return ERR_PTR(-ENOMEM); } 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 int xen_blkif_disconnect(struct xen_blkif *blkif) { if (blkif->xenblkd) { kthread_stop(blkif->xenblkd); wake_up(&blkif->shutdown_wq); blkif->xenblkd = NULL; } /* The above kthread_stop() guarantees that at this point we * don't have any discard_io or other_io requests. So, checking * for inflight IO is enough. */ if (atomic_read(&blkif->inflight) > 0) return -EBUSY; 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; } return 0; } static void xen_blkif_free(struct xen_blkif *blkif) { struct pending_req *req, *n; int i = 0, j; xen_blkif_disconnect(blkif); xen_vbd_free(&blkif->vbd); /* Remove all persistent grants and the cache of ballooned pages. */ xen_blkbk_free_caches(blkif); /* Make sure everything is drained before shutting down */ BUG_ON(blkif->persistent_gnt_c != 0); BUG_ON(atomic_read(&blkif->persistent_gnt_in_use) != 0); BUG_ON(blkif->free_pages_num != 0); BUG_ON(!list_empty(&blkif->persistent_purge_list)); BUG_ON(!list_empty(&blkif->free_pages)); BUG_ON(!RB_EMPTY_ROOT(&blkif->persistent_gnts)); /* Check that there is no request in use */ list_for_each_entry_safe(req, n, &blkif->pending_free, free_list) { list_del(&req->free_list); for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) kfree(req->segments[j]); for (j = 0; j < MAX_INDIRECT_PAGES; j++) kfree(req->indirect_pages[j]); kfree(req); i++; } WARN_ON(i != XEN_BLKIF_REQS); 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; } dev_set_drvdata(&dev->dev, NULL); if (be->blkif) { xen_blkif_disconnect(be->blkif); xen_blkif_put(be->blkif); } kfree(be->mode); kfree(be); 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, discard_enable; struct block_device *bdev = be->blkif->vbd.bdev; struct request_queue *q = bdev_get_queue(bdev); err = xenbus_scanf(XBT_NIL, dev->nodename, "discard-enable", "%d", &discard_enable); if (err == 1 && !discard_enable) return; 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 = kstrtoul(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. */ err = xen_blkif_disconnect(be->blkif); if (err) { xenbus_dev_fatal(dev, err, "pending I/O"); break; } 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, "feature-max-indirect-segments", "%u", MAX_INDIRECT_SEGMENTS); if (err) dev_warn(&dev->dev, "writing %s/feature-max-indirect-segments (%d)", dev->nodename, err); 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_printf(xbt, dev->nodename, "physical-sector-size", "%u", bdev_physical_block_size(be->blkif->vbd.bdev)); if (err) xenbus_dev_error(dev, err, "writing %s/physical-sector-size", dev->nodename); 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); }