[PATCH 10/17] md: raid1: remove direct access to bvec table in fix_sync_read_error

Ming Lei
2017-02-16T11:47:04Z

This patch uses a stack variable to hold the pages in bio, so
that we can remove direct access to bvec table in fix_sync_read_error().

This 16*8 stack variable is just fine for kernel thread context.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
---
drivers/md/raid1.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 1dd6b2760fba..02ee8542295d 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1874,6 +1874,16 @@ static int fix_sync_read_error(struct r1bio *r1_bio)
int sectors = r1_bio->sectors;
int idx = 0;
struct md_rdev *rdev;
+ struct bio_vec *bvl;
+ int i;
+ struct page *pages[RESYNC_PAGES];
+
+ /*
+ * bio for read_disk is filled up, so we can use
+ * bio_for_each_segment_all() to retrieve all pages.
+ */
+ bio_for_each_segment_all(bvl, bio, i)
+ pages[i] = bvl->bv_page;

rdev = conf->mirrors[r1_bio->read_disk].rdev;
if (test_bit(FailFast, &rdev->flags)) {
@@ -1903,7 +1913,7 @@ static int fix_sync_read_error(struct r1bio *r1_bio)
*/
rdev = conf->mirrors[d].rdev;
if (sync_page_io(rdev, sect, s<<9,
- bio->bi_io_vec[idx].bv_page,
+ pages[idx],
REQ_OP_READ, 0, false)) {
success = 1;
break;
@@ -1958,7 +1968,7 @@ static int fix_sync_read_error(struct r1bio *r1_bio)
continue;
rdev = conf->mirrors[d].rdev;
if (r1_sync_page_io(rdev, sect, s,
- bio->bi_io_vec[idx].bv_page,
+ pages[idx],
WRITE) == 0) {
r1_bio->bios[d]->bi_end_io = NULL;
rdev_dec_pending(rdev, mddev);
@@ -1973,7 +1983,7 @@ static int fix_sync_read_error(struct r1bio *r1_bio)
continue;
rdev = conf->mirrors[d].rdev;
if (r1_sync_page_io(rdev, sect, s,
- bio->bi_io_vec[idx].bv_page,
+ pages[idx],
READ) != 0)
atomic_add(s, &rdev->corrected_errors);
}
--
2.7.4