[PATCH 021 of 29] md: md: use stripe_head_state in ops_run_io()

From: NeilBrown
Date: Fri Jun 27 2008 - 02:58:54 EST



From: Dan Williams <dan.j.williams@xxxxxxxxx>

In handle_stripe after taking sh->lock we sample some bits into 's' (struct
stripe_head_state):

s.syncing = test_bit(STRIPE_SYNCING, &sh->state);
s.expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state);
s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);

Use these values from 's' in ops_run_io() rather than re-sampling the bits.
This ensures a consistent snapshot (as seen under sh->lock) is used.

Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Neil Brown <neilb@xxxxxxx>

### Diffstat output
./drivers/md/raid5.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)

diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c 2008-06-27 16:22:04.000000000 +1000
+++ ./drivers/md/raid5.c 2008-06-27 16:22:04.000000000 +1000
@@ -390,7 +390,7 @@ raid5_end_read_request(struct bio *bi, i
static void
raid5_end_write_request(struct bio *bi, int error);

-static void ops_run_io(struct stripe_head *sh)
+static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
{
raid5_conf_t *conf = sh->raid_conf;
int i, disks = sh->disks;
@@ -425,9 +425,7 @@ static void ops_run_io(struct stripe_hea
rcu_read_unlock();

if (rdev) {
- if (test_bit(STRIPE_SYNCING, &sh->state) ||
- test_bit(STRIPE_EXPAND_SOURCE, &sh->state) ||
- test_bit(STRIPE_EXPAND_READY, &sh->state))
+ if (s->syncing || s->expanding || s->expanded)
md_sync_acct(rdev->bdev, STRIPE_SECTORS);

set_bit(STRIPE_IO_STARTED, &sh->state);
@@ -2902,10 +2900,9 @@ static void handle_stripe5(struct stripe
if (pending)
raid5_run_ops(sh, pending);

- ops_run_io(sh);
+ ops_run_io(sh, &s);

return_io(return_bi);
-
}

static void handle_stripe6(struct stripe_head *sh, struct page *tmp_page)
--
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