Merge tag 'dm-3.4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm

Pull device-mapper fixes from Alasdair G Kergon:
 "Fix a couple of serious memory leaks in device-mapper thin
  provisioning and tidy its MODULE_DESCRIPTION.

  Mitigate occasional reported hangs associated with multipath scsi_dh
  module loading."

* tag 'dm-3.4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm:
  dm mpath: check if scsi_dh module already loaded before trying to load
  dm thin: correct module description
  dm thin: fix unprotected use of prepared_discards list
  dm thin: reinstate missing mempool_free in cell_release_singleton

2 files changed, 14 insertions, 6 deletions

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 922a3385eead..754f38f8a692 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -718,8 +718,8 @@ static int parse_hw_handler(struct dm_arg_set *as, struct multipath *m)
                 return 0;
 
         m->hw_handler_name = kstrdup(dm_shift_arg(as), GFP_KERNEL);
-        request_module("scsi_dh_%s", m->hw_handler_name);
-        if (scsi_dh_handler_exist(m->hw_handler_name) == 0) {
+        if (!try_then_request_module(scsi_dh_handler_exist(m->hw_handler_name),
+                                     "scsi_dh_%s", m->hw_handler_name)) {
                 ti->error = "unknown hardware handler type";
                 ret = -EINVAL;
                 goto fail;
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 213ae32a0fc4..2fd87b544a93 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -279,8 +279,10 @@ static void __cell_release(struct cell *cell, struct bio_list *inmates)
 
         hlist_del(&cell->list);
 
-        bio_list_add(inmates, cell->holder);
-        bio_list_merge(inmates, &cell->bios);
+        if (inmates) {
+                bio_list_add(inmates, cell->holder);
+                bio_list_merge(inmates, &cell->bios);
+        }
 
         mempool_free(cell, prison->cell_pool);
 }
@@ -303,9 +305,10 @@ static void cell_release(struct cell *cell, struct bio_list *bios)
  */
 static void __cell_release_singleton(struct cell *cell, struct bio *bio)
 {
-        hlist_del(&cell->list);
         BUG_ON(cell->holder != bio);
         BUG_ON(!bio_list_empty(&cell->bios));
+
+        __cell_release(cell, NULL);
 }
 
 static void cell_release_singleton(struct cell *cell, struct bio *bio)
@@ -1177,6 +1180,7 @@ static void no_space(struct cell *cell)
 static void process_discard(struct thin_c *tc, struct bio *bio)
 {
         int r;
+        unsigned long flags;
         struct pool *pool = tc->pool;
         struct cell *cell, *cell2;
         struct cell_key key, key2;
@@ -1218,7 +1222,9 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
                         m->bio = bio;
 
                         if (!ds_add_work(&pool->all_io_ds, &m->list)) {
+                                spin_lock_irqsave(&pool->lock, flags);
                                 list_add(&m->list, &pool->prepared_discards);
+                                spin_unlock_irqrestore(&pool->lock, flags);
                                 wake_worker(pool);
                         }
                 } else {
@@ -2626,8 +2632,10 @@ static int thin_endio(struct dm_target *ti,
         if (h->all_io_entry) {
                 INIT_LIST_HEAD(&work);
                 ds_dec(h->all_io_entry, &work);
+                spin_lock_irqsave(&pool->lock, flags);
                 list_for_each_entry_safe(m, tmp, &work, list)
                         list_add(&m->list, &pool->prepared_discards);
+                spin_unlock_irqrestore(&pool->lock, flags);
         }
 
         mempool_free(h, pool->endio_hook_pool);
@@ -2759,6 +2767,6 @@ static void dm_thin_exit(void)
 module_init(dm_thin_init);
 module_exit(dm_thin_exit);
 
-MODULE_DESCRIPTION(DM_NAME "device-mapper thin provisioning target");
+MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
 MODULE_LICENSE("GPL");