diff options
Diffstat (limited to 'drivers/block/xen-blkback/xenbus.c')
| -rw-r--r-- | drivers/block/xen-blkback/xenbus.c | 53 |
1 files changed, 40 insertions, 13 deletions
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index 9a547e6b6ebf..3a8b810b4980 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -35,12 +35,26 @@ 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; @@ -121,7 +135,6 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid) 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; spin_lock_init(&blkif->free_pages_lock); INIT_LIST_HEAD(&blkif->free_pages); @@ -132,6 +145,7 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid) 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); @@ -231,7 +245,7 @@ static int xen_blkif_map(struct xen_blkif *blkif, unsigned long shared_page, return 0; } -static void xen_blkif_disconnect(struct xen_blkif *blkif) +static int xen_blkif_disconnect(struct xen_blkif *blkif) { if (blkif->xenblkd) { kthread_stop(blkif->xenblkd); @@ -239,9 +253,12 @@ static void xen_blkif_disconnect(struct xen_blkif *blkif) blkif->xenblkd = NULL; } - atomic_dec(&blkif->refcnt); - wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0); - atomic_inc(&blkif->refcnt); + /* 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); @@ -252,6 +269,8 @@ static void xen_blkif_disconnect(struct xen_blkif *blkif) 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) @@ -259,8 +278,8 @@ static void xen_blkif_free(struct xen_blkif *blkif) struct pending_req *req, *n; int i = 0, j; - if (!atomic_dec_and_test(&blkif->refcnt)) - BUG(); + xen_blkif_disconnect(blkif); + xen_vbd_free(&blkif->vbd); /* Remove all persistent grants and the cache of ballooned pages. */ xen_blkbk_free_caches(blkif); @@ -449,16 +468,15 @@ static int xen_blkbk_remove(struct xenbus_device *dev) be->backend_watch.node = NULL; } + dev_set_drvdata(&dev->dev, NULL); + if (be->blkif) { xen_blkif_disconnect(be->blkif); - xen_vbd_free(&be->blkif->vbd); - xen_blkif_free(be->blkif); - be->blkif = NULL; + xen_blkif_put(be->blkif); } kfree(be->mode); kfree(be); - dev_set_drvdata(&dev->dev, NULL); return 0; } @@ -481,10 +499,15 @@ static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info struct xenbus_device *dev = be->dev; struct xen_blkif *blkif = be->blkif; int err; - int state = 0; + 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", @@ -700,7 +723,11 @@ static void frontend_changed(struct xenbus_device *dev, * Enforce precondition before potential leak point. * xen_blkif_disconnect() is idempotent. */ - xen_blkif_disconnect(be->blkif); + err = xen_blkif_disconnect(be->blkif); + if (err) { + xenbus_dev_fatal(dev, err, "pending I/O"); + break; + } err = connect_ring(be); if (err) |