Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964856Ab2HVREk (ORCPT ); Wed, 22 Aug 2012 13:04:40 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:54921 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964802Ab2HVREd (ORCPT ); Wed, 22 Aug 2012 13:04:33 -0400 From: Kent Overstreet To: linux-bcache@vger.kernel.org, linux-kernel@vger.kernel.org, dm-devel@redhat.com Cc: Kent Overstreet , tj@kernel.org, vgoyal@redhat.com, mpatocka@redhat.com, bharrosh@panasas.com, Jens Axboe Subject: [PATCH v6 03/13] block: Add bio_reset() Date: Wed, 22 Aug 2012 10:04:00 -0700 Message-Id: <1345655050-28199-4-git-send-email-koverstreet@google.com> X-Mailer: git-send-email 1.7.12 In-Reply-To: <1345655050-28199-1-git-send-email-koverstreet@google.com> References: <1345655050-28199-1-git-send-email-koverstreet@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3019 Lines: 97 Reusing bios is something that's been highly frowned upon in the past, but driver code keeps doing it anyways. If it's going to happen anyways, we should provide a generic method. This'll help with getting rid of bi_destructor - drivers/block/pktcdvd.c was open coding it, by doing a bio_init() and resetting bi_destructor. v5: Add a define BIO_RESET_BITS, to be very explicit about what parts of bio->bi_flags are saved. v6: Further commenting verbosity, per Tejun Signed-off-by: Kent Overstreet CC: Jens Axboe --- fs/bio.c | 9 +++++++++ include/linux/bio.h | 1 + include/linux/blk_types.h | 13 +++++++++++++ 3 files changed, 23 insertions(+) diff --git a/fs/bio.c b/fs/bio.c index 86e0534..81bdf4f 100644 --- a/fs/bio.c +++ b/fs/bio.c @@ -261,6 +261,15 @@ void bio_init(struct bio *bio) } EXPORT_SYMBOL(bio_init); +void bio_reset(struct bio *bio) +{ + unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS); + + memset(bio, 0, BIO_RESET_BYTES); + bio->bi_flags = flags|(1 << BIO_UPTODATE); +} +EXPORT_SYMBOL(bio_reset); + /** * bio_alloc_bioset - allocate a bio for I/O * @gfp_mask: the GFP_ mask given to the slab allocator diff --git a/include/linux/bio.h b/include/linux/bio.h index 2643589..ba60319 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -226,6 +226,7 @@ extern void __bio_clone(struct bio *, struct bio *); extern struct bio *bio_clone(struct bio *, gfp_t); extern void bio_init(struct bio *); +extern void bio_reset(struct bio *); extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int); extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *, diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index af9dd9d..4fe4984 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -59,6 +59,10 @@ struct bio { unsigned int bi_seg_front_size; unsigned int bi_seg_back_size; + /* + * Everything starting with bi_max_vecs will be preserved by bio_reset() + */ + unsigned int bi_max_vecs; /* max bvl_vecs we can hold */ atomic_t bi_cnt; /* pin count */ @@ -93,6 +97,8 @@ struct bio { struct bio_vec bi_inline_vecs[0]; }; +#define BIO_RESET_BYTES offsetof(struct bio, bi_max_vecs) + /* * bio flags */ @@ -108,6 +114,13 @@ 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 */ + +/* + * Flags starting here get preserved by bio_reset() - this includes + * BIO_POOL_IDX() + */ +#define BIO_RESET_BITS 12 + #define bio_flagged(bio, flag) ((bio)->bi_flags & (1 << (flag))) /* -- 1.7.12 -- 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/