[PATCH 3.13 147/149] bio-integrity: Fix bio_integrity_verify segment start bug

From: Greg Kroah-Hartman
Date: Thu Mar 20 2014 - 20:05:54 EST

3.13-stable review patch. If anyone has any objections, please let me know.


From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>

commit 5837c80e870bc3b12ac6a98cdc9ce7a9522a8fb6 upstream.

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.

(Context change for v3.10.y -> v3.13.y code - nab)

Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

fs/bio-integrity.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/bio-integrity.c
+++ b/fs/bio-integrity.c
@@ -458,7 +458,7 @@ static int bio_integrity_verify(struct b
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;

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