3 files changed, 33 insertions, 10 deletions

diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index 1c46f97d6664..ea49834377c8 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -287,7 +287,8 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where,
         unsigned num_bvecs;
         sector_t remaining = where->count;
         struct request_queue *q = bdev_get_queue(where->bdev);
-        sector_t discard_sectors;
+        unsigned short logical_block_size = queue_logical_block_size(q);
+        sector_t num_sectors;
 
         /*
          * where->count may be zero if rw holds a flush and we need to
@@ -297,7 +298,7 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where,
                 /*
                  * Allocate a suitably sized-bio.
                  */
-                if (rw & REQ_DISCARD)
+                if ((rw & REQ_DISCARD) || (rw & REQ_WRITE_SAME))
                         num_bvecs = 1;
                 else
                         num_bvecs = min_t(int, bio_get_nr_vecs(where->bdev),
@@ -310,9 +311,21 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where,
                 store_io_and_region_in_bio(bio, io, region);
 
                 if (rw & REQ_DISCARD) {
-                        discard_sectors = min_t(sector_t, q->limits.max_discard_sectors, remaining);
-                        bio->bi_size = discard_sectors << SECTOR_SHIFT;
-                        remaining -= discard_sectors;
+                        num_sectors = min_t(sector_t, q->limits.max_discard_sectors, remaining);
+                        bio->bi_size = num_sectors << SECTOR_SHIFT;
+                        remaining -= num_sectors;
+                } else if (rw & REQ_WRITE_SAME) {
+                        /*
+                         * WRITE SAME only uses a single page.
+                         */
+                        dp->get_page(dp, &page, &len, &offset);
+                        bio_add_page(bio, page, logical_block_size, offset);
+                        num_sectors = min_t(sector_t, q->limits.max_write_same_sectors, remaining);
+                        bio->bi_size = num_sectors << SECTOR_SHIFT;
+
+                        offset = 0;
+                        remaining -= num_sectors;
+                        dp->next_page(dp);
                 } else while (remaining) {
                         /*
                          * Try and add as many pages as possible.
diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c
index bed444c93d8d..68c02673263b 100644
--- a/drivers/md/dm-kcopyd.c
+++ b/drivers/md/dm-kcopyd.c
@@ -349,7 +349,7 @@ static void complete_io(unsigned long error, void *context)
         struct dm_kcopyd_client *kc = job->kc;
 
         if (error) {
-                if (job->rw == WRITE)
+                if (job->rw & WRITE)
                         job->write_err |= error;
                 else
                         job->read_err = 1;
@@ -361,7 +361,7 @@ static void complete_io(unsigned long error, void *context)
                 }
         }
 
-        if (job->rw == WRITE)
+        if (job->rw & WRITE)
                 push(&kc->complete_jobs, job);
 
         else {
@@ -432,7 +432,7 @@ static int process_jobs(struct list_head *jobs, struct dm_kcopyd_client *kc,
 
                 if (r < 0) {
                         /* error this rogue job */
-                        if (job->rw == WRITE)
+                        if (job->rw & WRITE)
                                 job->write_err = (unsigned long) -1L;
                         else
                                 job->read_err = 1;
@@ -585,6 +585,7 @@ int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
                    unsigned int flags, dm_kcopyd_notify_fn fn, void *context)
 {
         struct kcopyd_job *job;
+        int i;
 
         /*
          * Allocate an array of jobs consisting of one master job
@@ -611,7 +612,16 @@ int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
                 memset(&job->source, 0, sizeof job->source);
                 job->source.count = job->dests[0].count;
                 job->pages = &zero_page_list;
-                job->rw = WRITE;
+
+                /*
+                 * Use WRITE SAME to optimize zeroing if all dests support it.
+                 */
+                job->rw = WRITE | REQ_WRITE_SAME;
+                for (i = 0; i < job->num_dests; i++)
+                        if (!bdev_write_same(job->dests[i].bdev)) {
+                                job->rw = WRITE;
+                                break;
+                        }
         }
 
         job->fn = fn;
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index fba378f234a5..4b940745ba9e 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -2779,7 +2779,7 @@ static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits)
 
 static struct target_type thin_target = {
         .name = "thin",
-        .version = {1, 5, 0},
+        .version = {1, 6, 0},
         .module = THIS_MODULE,
         .ctr = thin_ctr,
         .dtr = thin_dtr,