On Mon, Sep 24, 2012 at 03:34:41PM -0700, Kent Overstreet wrote: > 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 <[email protected]> > CC: Jens Axboe <[email protected]> > CC: Martin K. Petersen <[email protected]> > --- > 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 -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
