Merge tag 'v3.3-rc7' into x86/mce

Merge reason: Update from an ancient -rc1 base to an almost-final stable kernel.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 16 insertions, 7 deletions

diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index ad2eba40e319..ea5dd289fe2a 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -296,6 +296,8 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where,
         unsigned offset;
         unsigned num_bvecs;
         sector_t remaining = where->count;
+        struct request_queue *q = bdev_get_queue(where->bdev);
+        sector_t discard_sectors;
 
         /*
          * where->count may be zero if rw holds a flush and we need to
@@ -305,9 +307,12 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where,
                 /*
                  * Allocate a suitably sized-bio.
                  */
-                num_bvecs = dm_sector_div_up(remaining,
-                                             (PAGE_SIZE >> SECTOR_SHIFT));
-                num_bvecs = min_t(int, bio_get_nr_vecs(where->bdev), num_bvecs);
+                if (rw & REQ_DISCARD)
+                        num_bvecs = 1;
+                else
+                        num_bvecs = min_t(int, bio_get_nr_vecs(where->bdev),
+                                          dm_sector_div_up(remaining, (PAGE_SIZE >> SECTOR_SHIFT)));
+
                 bio = bio_alloc_bioset(GFP_NOIO, num_bvecs, io->client->bios);
                 bio->bi_sector = where->sector + (where->count - remaining);
                 bio->bi_bdev = where->bdev;
@@ -315,10 +320,14 @@ static void do_region(int rw, unsigned region, struct dm_io_region *where,
                 bio->bi_destructor = dm_bio_destructor;
                 store_io_and_region_in_bio(bio, io, region);
 
-                /*
-                 * Try and add as many pages as possible.
-                 */
-                while (remaining) {
+                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;
+                } else while (remaining) {
+                        /*
+                         * Try and add as many pages as possible.
+                         */
                         dp->get_page(dp, &page, &len, &offset);
                         len = min(len, to_bytes(remaining));
                         if (!bio_add_page(bio, page, len, offset))