On Mon, Sep 24, 2012 at 03:34:41PM -0700, Kent Overstreet wrote:
quoted hunk ↗ jump to hunk
bio_integrity_split() seemed to be confusing pointers and arrays -
bip_vec in bio_integrity_payload is an array appended to the end of the
payload, so the bio_vecs in struct bio_pair need to come immediately
after the bio_integrity_payload they're for, and there was an assignment
in bio_integrity_split() that didn't make any sense.
Signed-off-by: Kent Overstreet <redacted>
CC: Jens Axboe <redacted>
CC: Martin K. Petersen <redacted>
---
fs/bio-integrity.c | 3 ---
include/linux/bio.h | 6 ++++--
2 files changed, 4 insertions(+), 5 deletions(-)
diff --git a/fs/bio-integrity.c b/fs/bio-integrity.c
index a3f28f3..c7b6b52 100644
--- a/fs/bio-integrity.c
+++ b/fs/bio-integrity.c
@@ -697,9 +697,6 @@ void bio_integrity_split(struct bio *bio, struct bio_pair *bp, int sectors)
bp->iv1 = bip->bip_vec[0];
bp->iv2 = bip->bip_vec[0];
- bp->bip1.bip_vec[0] = bp->iv1;
- bp->bip2.bip_vec[0] = bp->iv2;
-
bp->iv1.bv_len = sectors * bi->tuple_size;
bp->iv2.bv_offset += sectors * bi->tuple_size;
bp->iv2.bv_len -= sectors * bi->tuple_size;
diff --git a/include/linux/bio.h b/include/linux/bio.h
index b31036f..8e2d108 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -200,8 +200,10 @@ struct bio_pair {
struct bio bio1, bio2;
struct bio_vec bv1, bv2;
#if defined(CONFIG_BLK_DEV_INTEGRITY)
- struct bio_integrity_payload bip1, bip2;
- struct bio_vec iv1, iv2;
+ struct bio_integrity_payload bip1;
+ struct bio_vec iv1;
+ struct bio_integrity_payload bip2;
+ struct bio_vec iv2;
#endif
I think it probably is a good idea to put a comment here so that we
know that certain elements of structure assume ordering.
Also I am wondering that what's the gurantee that there are no padding
bytes between bipi1 and iv1 (or bip2 or iv2). I think if there are padding
bytes then the assumption that bio_vec is always following bip will be
broken?
Also had a general question about split logic. We seem to have only one
global pool for bio pair (bio_split_pool). So in the IO stack if we split
a bio more than once, we have the deadlock possibility again?
Thanks
Vivek