[PATCH] md: do not use ++ in rcu_dereference() argument

Kulikov Vasiliy
2010-09-05T18:32:18Z

From: Vasiliy Kulikov <segooon@gmail.com>

rcu_dereference() is macro, so it might use its argument twice.
Argument must not has side effects.

It was found by compiler warning:
drivers/md/raid1.c: In function ‘read_balance’:
drivers/md/raid1.c:445: warning: operation on ‘new_disk’ may be undefined

Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
---
drivers/md/raid1.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index ad83a4d..12194df 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -442,7 +442,7 @@ static int read_balance(conf_t *conf, r1bio_t *r1_bio)
r1_bio->bios[new_disk] = IO_BLOCKED ||
!rdev || !test_bit(In_sync, &rdev->flags)
|| test_bit(WriteMostly, &rdev->flags);
- rdev = rcu_dereference(conf->mirrors[++new_disk].rdev)) {
+ rdev = rcu_dereference(conf->mirrors[new_disk].rdev)) {

if (rdev && test_bit(In_sync, &rdev->flags) &&
r1_bio->bios[new_disk] != IO_BLOCKED)
@@ -452,6 +452,7 @@ static int read_balance(conf_t *conf, r1bio_t *r1_bio)
new_disk = wonly_disk;
break;
}
+ new_disk++;
}
goto rb_out;
}
--
1.7.0.4