Re: [PATCH v2 13/13] md: raid10: avoid direct access to bvec table in handle_reshape_read_error
flat view
From: Shaohua Li <shli@kernel.org>
Date: 2017-02-28 23:48:22
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linux-block
On Tue, Feb 28, 2017 at 11:41:43PM +0800, Ming Lei wrote:
quoted hunk ↗ jump to hunk
The cost is 128bytes(8*16) stack space in kernel thread context, and just use the bio helper to retrieve pages from bio. Signed-off-by: Ming Lei <tom.leiming@gmail.com> --- drivers/md/raid10.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 0b97631e3905..6ffb64ab45f8 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c@@ -4670,7 +4670,15 @@ static int handle_reshape_read_error(struct mddev *mddev, struct r10bio *r10b = &on_stack.r10_bio; int slot = 0; int idx = 0; - struct bio_vec *bvec = r10_bio->master_bio->bi_io_vec; + struct bio_vec *bvl; + struct page *pages[RESYNC_PAGES]; + + /* + * This bio is allocated in reshape_request(), and size + * is still RESYNC_PAGES + */ + bio_for_each_segment_all(bvl, r10_bio->master_bio, idx) + pages[idx] = bvl->bv_page;
The reshape bio is doing IO against the memory we allocated for r10_bio, I'm wondering why we can't get the pages from r10_bio. In this way, we don't need access the bio_vec any more. Thanks, Shaohua
quoted hunk ↗ jump to hunk
r10b->sector = r10_bio->sector; __raid10_find_phys(&conf->prev, r10b);@@ -4699,7 +4707,7 @@ static int handle_reshape_read_error(struct mddev *mddev, success = sync_page_io(rdev, addr, s << 9, - bvec[idx].bv_page, + pages[idx], REQ_OP_READ, 0, false); rdev_dec_pending(rdev, mddev); rcu_read_lock();-- 2.7.4