[PATCH] bio-integrity: Fix bio_integrity_verify segment start bug

[Nicholas Bellinger]

This patch addresses a bug in bio_integrity_verify() code that has
been causing DIF READ verify operations to be silently skipped.

The issue is that bio->bi_idx will have been incremented within
bio_advance() code in the normal blk_update_request() ->
req_bio_endio() completion path, and bio_integrity_verify() is
using bio_for_each_segment() which starts the bio segment walk
at the current bio->bi_idx.

So instead use bio_for_each_segment_all() to always start the bio
segment walk from zero, regardless of the current bio->bi_idx
value after bio_advance() has been called.

Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
---
 fs/bio-integrity.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/bio-integrity.c b/fs/bio-integrity.c
index fc60b31..f1d5cde 100644
--- a/fs/bio-integrity.c
+++ b/fs/bio-integrity.c
@@ -450,7 +450,7 @@ static int bio_integrity_verify(struct bio *bio)
 	bix.disk_name = bio->bi_bdev->bd_disk->disk_name;
 	bix.sector_size = bi->sector_size;
 
-	bio_for_each_segment(bv, bio, i) {
+	bio_for_each_segment_all(bv, bio, i) {
 		void *kaddr = kmap_atomic(bv->bv_page);
 		bix.data_buf = kaddr + bv->bv_offset;
 		bix.data_size = bv->bv_len;
-- 
1.7.10.4

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