block/bounce: count bytes instead of sectors

Individual bv_len's may not be a sector size.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Pankaj Raghav <p.raghav@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220610195830.3574005-8-kbusch@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/bounce.c b/block/bounce.c
index 8f7b6fe3b4db5f621e5efce566ab3e9697b44fd9..c8f487af7be374b3087934b49bb475dd3fa05f0a 100644 (file)
--- a/block/bounce.c
+++ b/block/bounce.c
@@ -205,19 +205,26 @@ void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
        int rw = bio_data_dir(*bio_orig);
        struct bio_vec *to, from;
        struct bvec_iter iter;
-       unsigned i = 0;
+       unsigned i = 0, bytes = 0;
        bool bounce = false;
-       int sectors = 0;
+       int sectors;
 
        bio_for_each_segment(from, *bio_orig, iter) {
                if (i++ < BIO_MAX_VECS)
-                       sectors += from.bv_len >> 9;
+                       bytes += from.bv_len;
                if (PageHighMem(from.bv_page))
                        bounce = true;
        }
        if (!bounce)
                return;
 
+       /*
+        * Individual bvecs might not be logical block aligned. Round down
+        * the split size so that each bio is properly block size aligned,
+        * even if we do not use the full hardware limits.
+        */
+       sectors = ALIGN_DOWN(bytes, queue_logical_block_size(q)) >>
+                       SECTOR_SHIFT;
        if (sectors < bio_sectors(*bio_orig)) {
                bio = bio_split(*bio_orig, sectors, GFP_NOIO, &bounce_bio_split);
                bio_chain(bio, *bio_orig);