Merge branch 'for-linus' of git://git.kernel.dk/linux-block

Pull block layer fix from Jens Axboe:
 "This just contains the fix for the split issue that we had in -rc1.

  It's been well tested at this point, so let's get it in mainline so we
  don't have the same split issue for -rc2"

* 'for-linus' of git://git.kernel.dk/linux-block:
  block: fix bio splitting on max sectors

1 files changed, 19 insertions, 7 deletions

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 1699df5b0493..888a7fec81f7 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -70,6 +70,18 @@ static struct bio *blk_bio_write_same_split(struct request_queue *q,
         return bio_split(bio, q->limits.max_write_same_sectors, GFP_NOIO, bs);
 }
 
+static inline unsigned get_max_io_size(struct request_queue *q,
+                                       struct bio *bio)
+{
+        unsigned sectors = blk_max_size_offset(q, bio->bi_iter.bi_sector);
+        unsigned mask = queue_logical_block_size(q) - 1;
+
+        /* aligned to logical block size */
+        sectors &= ~(mask >> 9);
+
+        return sectors;
+}
+
 static struct bio *blk_bio_segment_split(struct request_queue *q,
                                          struct bio *bio,
                                          struct bio_set *bs,
@@ -81,6 +93,7 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
         unsigned front_seg_size = bio->bi_seg_front_size;
         bool do_split = true;
         struct bio *new = NULL;
+        const unsigned max_sectors = get_max_io_size(q, bio);
 
         bio_for_each_segment(bv, bio, iter) {
                 /*
@@ -90,20 +103,19 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
                 if (bvprvp && bvec_gap_to_prev(q, bvprvp, bv.bv_offset))
                         goto split;
 
-                if (sectors + (bv.bv_len >> 9) >
-                                blk_max_size_offset(q, bio->bi_iter.bi_sector)) {
+                if (sectors + (bv.bv_len >> 9) > max_sectors) {
                         /*
                          * Consider this a new segment if we're splitting in
                          * the middle of this vector.
                          */
                         if (nsegs < queue_max_segments(q) &&
-                            sectors < blk_max_size_offset(q,
-                                                bio->bi_iter.bi_sector)) {
+                            sectors < max_sectors) {
                                 nsegs++;
-                                sectors = blk_max_size_offset(q,
-                                                bio->bi_iter.bi_sector);
+                                sectors = max_sectors;
                         }
-                        goto split;
+                        if (sectors)
+                                goto split;
+                        /* Make this single bvec as the 1st segment */
                 }
 
                 if (bvprvp && blk_queue_cluster(q)) {