diff options
Diffstat (limited to 'drivers/block/xen-blkback/xenbus.c')
-rw-r--r-- | drivers/block/xen-blkback/xenbus.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index 5dfe6e8af140..1d1f86657967 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -178,6 +178,15 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid) blkif->domid = domid; atomic_set(&blkif->refcnt, 1); init_completion(&blkif->drain_complete); + + /* + * Because freeing back to the cache may be deferred, it is not + * safe to unload the module (and hence destroy the cache) until + * this has completed. To prevent premature unloading, take an + * extra module reference here and release only when the object + * has been freed back to the cache. + */ + __module_get(THIS_MODULE); INIT_WORK(&blkif->free_work, xen_blkif_deferred_free); return blkif; @@ -322,6 +331,7 @@ static void xen_blkif_free(struct xen_blkif *blkif) /* Make sure everything is drained before shutting down */ kmem_cache_free(xen_blkif_cachep, blkif); + module_put(THIS_MODULE); } int __init xen_blkif_interface_init(void) @@ -967,6 +977,7 @@ static int read_per_ring_refs(struct xen_blkif_ring *ring, const char *dir) } blkif->nr_ring_pages = nr_grefs; + err = -ENOMEM; for (i = 0; i < nr_grefs * XEN_BLKIF_REQS_PER_PAGE; i++) { req = kzalloc(sizeof(*req), GFP_KERNEL); if (!req) @@ -989,7 +1000,7 @@ static int read_per_ring_refs(struct xen_blkif_ring *ring, const char *dir) err = xen_blkif_map(ring, ring_ref, nr_grefs, evtchn); if (err) { xenbus_dev_fatal(dev, err, "mapping ring-ref port %u", evtchn); - return err; + goto fail; } return 0; @@ -1009,8 +1020,7 @@ fail: } kfree(req); } - return -ENOMEM; - + return err; } static int connect_ring(struct backend_info *be) |