Merge tag 'dm-3.12-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device-mapper fixes from Mike Snitzer:
 "A few fixes for dm-snapshot, a 32 bit fix for dm-stats, a couple error
  handling fixes for dm-multipath.  A fix for the thin provisioning
  target to not expose non-zero discard limits if discards are disabled.

  Lastly, add two DM module parameters which allow users to tune the
  emergency memory reserves that DM mainatins per device -- this helps
  fix a long-standing issue for dm-multipath.  The conservative default
  reserve for request-based dm-multipath devices (256) has proven
  problematic for users with many multipathed SCSI devices but
  relatively little memory.  To responsibly select a smaller value users
  should use the new nr_bios tracepoint info (via commit 75afb352
  "block: Add nr_bios to block_rq_remap tracepoint") to determine the
  peak number of bios their workloads create"

* tag 'dm-3.12-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm: add reserved_bio_based_ios module parameter
  dm: add reserved_rq_based_ios module parameter
  dm: lower bio-based mempool reservation
  dm thin: do not expose non-zero discard limits if discards disabled
  dm mpath: disable WRITE SAME if it fails
  dm-snapshot: fix performance degradation due to small hash size
  dm snapshot: workaround for a false positive lockdep warning
  dm stats: fix possible counter corruption on 32-bit systems
  dm mpath: do not fail path on -ENOSPC

9 files changed, 120 insertions, 26 deletions

diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index ea49834377c8..2a20986a2fec 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -19,8 +19,6 @@
 #define DM_MSG_PREFIX "io"
 
 #define DM_IO_MAX_REGIONS       BITS_PER_LONG
-#define MIN_IOS         16
-#define MIN_BIOS        16
 
 struct dm_io_client {
         mempool_t *pool;
@@ -50,16 +48,17 @@ static struct kmem_cache *_dm_io_cache;
 struct dm_io_client *dm_io_client_create(void)
 {
         struct dm_io_client *client;
+        unsigned min_ios = dm_get_reserved_bio_based_ios();
 
         client = kmalloc(sizeof(*client), GFP_KERNEL);
         if (!client)
                 return ERR_PTR(-ENOMEM);
 
-        client->pool = mempool_create_slab_pool(MIN_IOS, _dm_io_cache);
+        client->pool = mempool_create_slab_pool(min_ios, _dm_io_cache);
         if (!client->pool)
                 goto bad;
 
-        client->bios = bioset_create(MIN_BIOS, 0);
+        client->bios = bioset_create(min_ios, 0);
         if (!client->bios)
                 goto bad;
 
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index b759a127f9c3..de570a558764 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -7,6 +7,7 @@
 
 #include <linux/device-mapper.h>
 
+#include "dm.h"
 #include "dm-path-selector.h"
 #include "dm-uevent.h"
 
@@ -116,8 +117,6 @@ struct dm_mpath_io {
 
 typedef int (*action_fn) (struct pgpath *pgpath);
 
-#define MIN_IOS 256     /* Mempool size */
-
 static struct kmem_cache *_mpio_cache;
 
 static struct workqueue_struct *kmultipathd, *kmpath_handlerd;
@@ -190,6 +189,7 @@ static void free_priority_group(struct priority_group *pg,
 static struct multipath *alloc_multipath(struct dm_target *ti)
 {
         struct multipath *m;
+        unsigned min_ios = dm_get_reserved_rq_based_ios();
 
         m = kzalloc(sizeof(*m), GFP_KERNEL);
         if (m) {
@@ -202,7 +202,7 @@ static struct multipath *alloc_multipath(struct dm_target *ti)
                 INIT_WORK(&m->trigger_event, trigger_event);
                 init_waitqueue_head(&m->pg_init_wait);
                 mutex_init(&m->work_mutex);
-                m->mpio_pool = mempool_create_slab_pool(MIN_IOS, _mpio_cache);
+                m->mpio_pool = mempool_create_slab_pool(min_ios, _mpio_cache);
                 if (!m->mpio_pool) {
                         kfree(m);
                         return NULL;
@@ -1268,6 +1268,7 @@ static int noretry_error(int error)
         case -EREMOTEIO:
         case -EILSEQ:
         case -ENODATA:
+        case -ENOSPC:
                 return 1;
         }
 
@@ -1298,8 +1299,17 @@ static int do_end_io(struct multipath *m, struct request *clone,
         if (!error && !clone->errors)
                 return 0;       /* I/O complete */
 
-        if (noretry_error(error))
+        if (noretry_error(error)) {
+                if ((clone->cmd_flags & REQ_WRITE_SAME) &&
+                    !clone->q->limits.max_write_same_sectors) {
+                        struct queue_limits *limits;
+
+                        /* device doesn't really support WRITE SAME, disable it */
+                        limits = dm_get_queue_limits(dm_table_get_md(m->ti->table));
+                        limits->max_write_same_sectors = 0;
+                }
                 return error;
+        }
 
         if (mpio->pgpath)
                 fail_path(mpio->pgpath);
diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c
index 3ac415675b6c..4caa8e6d59d7 100644
--- a/drivers/md/dm-snap-persistent.c
+++ b/drivers/md/dm-snap-persistent.c
@@ -256,7 +256,7 @@ static int chunk_io(struct pstore *ps, void *area, chunk_t chunk, int rw,
          */
         INIT_WORK_ONSTACK(&req.work, do_metadata);
         queue_work(ps->metadata_wq, &req.work);
-        flush_work(&req.work);
+        flush_workqueue(ps->metadata_wq);
 
         return req.result;
 }
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index c434e5aab2df..aec57d76db5d 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -725,17 +725,16 @@ static int calc_max_buckets(void)
  */
 static int init_hash_tables(struct dm_snapshot *s)
 {
-        sector_t hash_size, cow_dev_size, origin_dev_size, max_buckets;
+        sector_t hash_size, cow_dev_size, max_buckets;
 
         /*
          * Calculate based on the size of the original volume or
          * the COW volume...
          */
         cow_dev_size = get_dev_size(s->cow->bdev);
-        origin_dev_size = get_dev_size(s->origin->bdev);
         max_buckets = calc_max_buckets();
 
-        hash_size = min(origin_dev_size, cow_dev_size) >> s->store->chunk_shift;
+        hash_size = cow_dev_size >> s->store->chunk_shift;
         hash_size = min(hash_size, max_buckets);
 
         if (hash_size < 64)
diff --git a/drivers/md/dm-stats.c b/drivers/md/dm-stats.c
index 8ae31e8d3d64..3d404c1371ed 100644
--- a/drivers/md/dm-stats.c
+++ b/drivers/md/dm-stats.c
@@ -451,19 +451,26 @@ static void dm_stat_for_entry(struct dm_stat *s, size_t entry,
         struct dm_stat_percpu *p;
 
         /*
-         * For strict correctness we should use local_irq_disable/enable
+         * For strict correctness we should use local_irq_save/restore
          * instead of preempt_disable/enable.
          *
-         * This is racy if the driver finishes bios from non-interrupt
-         * context as well as from interrupt context or from more different
-         * interrupts.
+         * preempt_disable/enable is racy if the driver finishes bios
+         * from non-interrupt context as well as from interrupt context
+         * or from more different interrupts.
          *
-         * However, the race only results in not counting some events,
-         * so it is acceptable.
+         * On 64-bit architectures the race only results in not counting some
+         * events, so it is acceptable.  On 32-bit architectures the race could
+         * cause the counter going off by 2^32, so we need to do proper locking
+         * there.
          *
          * part_stat_lock()/part_stat_unlock() have this race too.
          */
+#if BITS_PER_LONG == 32
+        unsigned long flags;
+        local_irq_save(flags);
+#else
         preempt_disable();
+#endif