In the first loop of function raid10_handle_discard. It already
determines which disk need to handle discard request and add the
rdev reference count. So the conf->mirrors will not change until
all bios come back from underlayer disks. It doesn't need to use
rcu_dereference to get rdev.
Signed-off-by: Xiao Ni <xni@xxxxxxxxxx>
---
drivers/md/raid10.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 16977e8..cef9869 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1743,9 +1743,8 @@ static int raid10_handle_discard(struct mddev *mddev, struct bio *bio)
for (disk = 0; disk < geo->raid_disks; disk++) {
sector_t dev_start, dev_end;
struct bio *mbio, *rbio = NULL;
- struct md_rdev *rdev = rcu_dereference(conf->mirrors[disk].rdev);
- struct md_rdev *rrdev = rcu_dereference(
- conf->mirrors[disk].replacement);
+ struct md_rdev *rdev = conf->mirrors[disk].rdev;
+ struct md_rdev *rrdev = conf->mirrors[disk].replacement;
/*
* Now start to calculate the start and end address for each disk.
--
2.7.5
