Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964842Ab2EXQ6G (ORCPT ); Thu, 24 May 2012 12:58:06 -0400 Received: from natasha.panasas.com ([67.152.220.90]:50073 "EHLO natasha.panasas.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933723Ab2EXQ6D (ORCPT ); Thu, 24 May 2012 12:58:03 -0400 Message-ID: <4FBE687E.1030605@panasas.com> Date: Thu, 24 May 2012 19:57:34 +0300 From: Boaz Harrosh User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:8.0) Gecko/20111113 Thunderbird/8.0 MIME-Version: 1.0 To: Kent Overstreet CC: , , , , , , , , , , , , Subject: Re: [PATCH v2 09/14] block: Add an explicit bio flag for bios that own their bvec References: <1337817771-25038-1-git-send-email-koverstreet@google.com> <1337817771-25038-10-git-send-email-koverstreet@google.com> In-Reply-To: <1337817771-25038-10-git-send-email-koverstreet@google.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2763 Lines: 90 On 05/24/2012 03:02 AM, Kent Overstreet wrote: > This is for the new bio splitting code. When we split a bio, if the > split occured on a bvec boundry we reuse the bvec for the new bio. But > that means bio_free() can't free it, hence the explicit flag. > How do you insure that the original bio which owns the bvec is not freed before the split-out bio. Perhaps calling code needs to make sure by taking an extra ref on the original bio, or something. If so a big fat comment at bio_split is do. And I understand you did not like my suggestion of negating the meaning of the flag, so the default is zero? Please say why? Thanks Boaz > Signed-off-by: Kent Overstreet > Change-Id: I040f6b501088e882a9f013d6b6e730ff04e9c1da > --- > fs/bio.c | 3 ++- > include/linux/bio.h | 5 ----- > include/linux/blk_types.h | 1 + > 3 files changed, 3 insertions(+), 6 deletions(-) > > diff --git a/fs/bio.c b/fs/bio.c > index fc4a168..24b1d1c 100644 > --- a/fs/bio.c > +++ b/fs/bio.c > @@ -241,7 +241,7 @@ void bio_free(struct bio *bio, struct bio_set *bs) > return; > } > > - if (bio_has_allocated_vec(bio)) > + if (bio_flagged(bio, BIO_HAS_VEC)) > bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio)); > > if (bio_integrity(bio)) > @@ -312,6 +312,7 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs) > goto err_free; > > nr_iovecs = bvec_nr_vecs(idx); > + bio->bi_flags |= 1 << BIO_HAS_VEC; > } > out_set: > bio->bi_flags |= idx << BIO_POOL_OFFSET; > diff --git a/include/linux/bio.h b/include/linux/bio.h > index 35f7c4d..8dd8cae 100644 > --- a/include/linux/bio.h > +++ b/include/linux/bio.h > @@ -84,11 +84,6 @@ static inline void *bio_data(struct bio *bio) > return NULL; > } > > -static inline int bio_has_allocated_vec(struct bio *bio) > -{ > - return bio->bi_io_vec && bio->bi_io_vec != bio->bi_inline_vecs; > -} > - > /* > * will die > */ > diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h > index b6ddbf1..ab2252d 100644 > --- a/include/linux/blk_types.h > +++ b/include/linux/blk_types.h > @@ -101,6 +101,7 @@ struct bio { > #define BIO_FS_INTEGRITY 9 /* fs owns integrity data, not block layer */ > #define BIO_QUIET 10 /* Make BIO Quiet */ > #define BIO_MAPPED_INTEGRITY 11/* integrity metadata has been remapped */ > +#define BIO_HAS_VEC 12 /* bio_free() should free bvec */ > #define bio_flagged(bio, flag) ((bio)->bi_flags & (1 << (flag))) > > /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/