Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964793Ab2EYU0c (ORCPT ); Fri, 25 May 2012 16:26:32 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:36768 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758696Ab2EYU01 (ORCPT ); Fri, 25 May 2012 16:26:27 -0400 From: Kent Overstreet To: linux-kernel@vger.kernel.org, linux-bcache@vger.kernel.org, dm-devel@redhat.com, linux-fsdevel@vger.kernel.org Cc: Kent Overstreet , tj@kernel.org, axboe@kernel.dk, agk@redhat.com, neilb@suse.de, drbd-dev@lists.linbit.com, bharrosh@panasas.com, vgoyal@redhat.com, mpatocka@redhat.com, sage@newdream.net, yehuda@hq.newdream.net Subject: [PATCH v3 14/16] Gut bio_add_page() Date: Fri, 25 May 2012 13:25:37 -0700 Message-Id: <1337977539-16977-15-git-send-email-koverstreet@google.com> X-Mailer: git-send-email 1.7.9.3.327.g2980b In-Reply-To: <1337977539-16977-1-git-send-email-koverstreet@google.com> References: <1337977539-16977-1-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: 5867 Lines: 197 Since generic_make_request() can now handle arbitrary size bios, all we have to do is make sure the bvec array doesn't overflow. Signed-off-by: Kent Overstreet --- fs/bio.c | 133 ++++++++++++-------------------------------------------------- 1 file changed, 26 insertions(+), 107 deletions(-) diff --git a/fs/bio.c b/fs/bio.c index e4d54b2..b0c2944 100644 --- a/fs/bio.c +++ b/fs/bio.c @@ -570,12 +570,22 @@ int bio_get_nr_vecs(struct block_device *bdev) } EXPORT_SYMBOL(bio_get_nr_vecs); -static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page - *page, unsigned int len, unsigned int offset, - unsigned short max_sectors) +/** + * bio_add_page - attempt to add page to bio + * @bio: destination bio + * @page: page to add + * @len: vec entry length + * @offset: vec entry offset + * + * Attempt to add a page to the bio_vec maplist. This can fail for a + * number of reasons, such as the bio being full or target block device + * limitations. The target block device must allow bio's up to PAGE_SIZE, + * so it is always possible to add a single page to an empty bio. + */ +int bio_add_page(struct bio *bio, struct page *page, + unsigned int len, unsigned int offset) { - int retried_segments = 0; - struct bio_vec *bvec; + struct bio_vec *bv; /* * cloned bio must not modify vec list @@ -583,40 +593,17 @@ static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page if (unlikely(bio_flagged(bio, BIO_CLONED))) return 0; - if (((bio->bi_size + len) >> 9) > max_sectors) - return 0; - /* * For filesystems with a blocksize smaller than the pagesize * we will often be called with the same page as last time and * a consecutive offset. Optimize this special case. */ if (bio->bi_vcnt > 0) { - struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1]; - - if (page == prev->bv_page && - offset == prev->bv_offset + prev->bv_len) { - unsigned int prev_bv_len = prev->bv_len; - prev->bv_len += len; - - if (q->merge_bvec_fn) { - struct bvec_merge_data bvm = { - /* prev_bvec is already charged in - bi_size, discharge it in order to - simulate merging updated prev_bvec - as new bvec. */ - .bi_bdev = bio->bi_bdev, - .bi_sector = bio->bi_sector, - .bi_size = bio->bi_size - prev_bv_len, - .bi_rw = bio->bi_rw, - }; - - if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len) { - prev->bv_len -= len; - return 0; - } - } + bv = bio_iovec_idx(bio, bio->bi_vcnt - 1); + if (page == bv->bv_page && + offset == bv->bv_offset + bv->bv_len) { + bv->bv_len += len; goto done; } } @@ -624,64 +611,17 @@ static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page if (bio->bi_vcnt >= bio->bi_max_vecs) return 0; - /* - * we might lose a segment or two here, but rather that than - * make this too complex. - */ - - while (bio->bi_phys_segments >= queue_max_segments(q)) { - - if (retried_segments) - return 0; - - retried_segments = 1; - blk_recount_segments(q, bio); - } - - /* - * setup the new entry, we might clear it again later if we - * cannot add the page - */ - bvec = &bio->bi_io_vec[bio->bi_vcnt]; - bvec->bv_page = page; - bvec->bv_len = len; - bvec->bv_offset = offset; - - /* - * if queue has other restrictions (eg varying max sector size - * depending on offset), it can specify a merge_bvec_fn in the - * queue to get further control - */ - if (q->merge_bvec_fn) { - struct bvec_merge_data bvm = { - .bi_bdev = bio->bi_bdev, - .bi_sector = bio->bi_sector, - .bi_size = bio->bi_size, - .bi_rw = bio->bi_rw, - }; - - /* - * merge_bvec_fn() returns number of bytes it can accept - * at this offset - */ - if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len) { - bvec->bv_page = NULL; - bvec->bv_len = 0; - bvec->bv_offset = 0; - return 0; - } - } - - /* If we may be able to merge these biovecs, force a recount */ - if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec))) - bio->bi_flags &= ~(1 << BIO_SEG_VALID); + bv = bio_iovec_idx(bio, bio->bi_vcnt); + bv->bv_page = page; + bv->bv_len = len; + bv->bv_offset = offset; bio->bi_vcnt++; - bio->bi_phys_segments++; - done: +done: bio->bi_size += len; return len; } +EXPORT_SYMBOL(bio_add_page); /** * bio_add_pc_page - attempt to add page to bio @@ -701,31 +641,10 @@ static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page, unsigned int len, unsigned int offset) { - return __bio_add_page(q, bio, page, len, offset, - queue_max_hw_sectors(q)); + return bio_add_page(bio, page, len, offset); } EXPORT_SYMBOL(bio_add_pc_page); -/** - * bio_add_page - attempt to add page to bio - * @bio: destination bio - * @page: page to add - * @len: vec entry length - * @offset: vec entry offset - * - * Attempt to add a page to the bio_vec maplist. This can fail for a - * number of reasons, such as the bio being full or target block device - * limitations. The target block device must allow bio's up to PAGE_SIZE, - * so it is always possible to add a single page to an empty bio. - */ -int bio_add_page(struct bio *bio, struct page *page, unsigned int len, - unsigned int offset) -{ - struct request_queue *q = bdev_get_queue(bio->bi_bdev); - return __bio_add_page(q, bio, page, len, offset, queue_max_sectors(q)); -} -EXPORT_SYMBOL(bio_add_page); - struct bio_map_data { struct bio_vec *iovecs; struct sg_iovec *sgvecs; -- 1.7.9.3.327.g2980b -- 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/