From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ming Lei Subject: [PATCH 04/17] md: introduce helpers for dealing with fetch/store preallocated pages in bio Date: Thu, 16 Feb 2017 19:45:34 +0800 Message-ID: <1487245547-24384-5-git-send-email-tom.leiming@gmail.com> References: <1487245547-24384-1-git-send-email-tom.leiming@gmail.com> Return-path: In-Reply-To: <1487245547-24384-1-git-send-email-tom.leiming@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Shaohua Li , Jens Axboe , linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, linux-block@vger.kernel.org, Christoph Hellwig , NeilBrown Cc: Ming Lei List-Id: linux-raid.ids Both raid1 and raid10 uses bio's bvec table to store pre-allocated pages, then fetch and add it to bio. This patch introduces two helpers for dealing with the special case, like what bio_iov_iter_get_pages() does. Signed-off-by: Ming Lei --- drivers/md/md.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/drivers/md/md.h b/drivers/md/md.h index a86ad62079de..21897cb514af 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -708,4 +708,25 @@ static inline void mddev_clear_unsupported_flags(struct mddev *mddev, { mddev->flags &= ~unsupported_flags; } + +/* + * Both raid1 and raid10 use bio's bvec table to store the preallocated + * pages, so we introduces the following helpers for this kind of usage. + * + * Actually the usage is a bit similar with bio_iov_iter_get_pages(). + * + * Please make sure .bi_io_vec[idx] points to one unused vector by the + * bio. + */ +static inline struct page *mdev_get_page_from_bio(struct bio *bio, unsigned idx) +{ + return bio->bi_io_vec[idx].bv_page; +} + +static inline void mdev_put_page_to_bio(struct bio *bio, unsigned idx, + struct page *page) +{ + bio->bi_io_vec[idx].bv_page = page; +} + #endif /* _MD_MD_H */ -- 2.7.4