md/raid5: fix spares errors about rcu usage

As commit ad860670 ("md/raid5: remove rcu protection to access rdev
from conf") explains, rcu protection can be removed, however, there are
three places left, there won't be any real problems.

drivers/md/raid5.c:8071:24: error: incompatible types in comparison expression (different address spaces):
drivers/md/raid5.c:8071:24:    struct md_rdev [noderef] __rcu *
drivers/md/raid5.c:8071:24:    struct md_rdev *
drivers/md/raid5.c:7569:25: error: incompatible types in comparison expression (different address spaces):
drivers/md/raid5.c:7569:25:    struct md_rdev [noderef] __rcu *
drivers/md/raid5.c:7569:25:    struct md_rdev *
drivers/md/raid5.c:7573:25: error: incompatible types in comparison expression (different address spaces):
drivers/md/raid5.c:7573:25:    struct md_rdev [noderef] __rcu *
drivers/md/raid5.c:7573:25:    struct md_rdev *

Fixes: ad860670 ("md/raid5: remove rcu protection to access rdev from conf")
Cc: stable@vger.kernel.org
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20240615085143.1648223-1-yukuai1@huaweicloud.com

drivers/md/raid5.c

@@ -155,7 +155,7 @@ static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
 	return slot;
 }
 
-static void print_raid5_conf (struct r5conf *conf);
+static void print_raid5_conf(struct r5conf *conf);
 
 static int stripe_operations_active(struct stripe_head *sh)
 {
@@ -7568,11 +7568,11 @@ static struct r5conf *setup_conf(struct mddev *mddev)
 		if (test_bit(Replacement, &rdev->flags)) {
 			if (disk->replacement)
 				goto abort;
-			RCU_INIT_POINTER(disk->replacement, rdev);
+			disk->replacement = rdev;
 		} else {
 			if (disk->rdev)
 				goto abort;
-			RCU_INIT_POINTER(disk->rdev, rdev);
+			disk->rdev = rdev;
 		}
 
 		if (test_bit(In_sync, &rdev->flags)) {
@@ -8054,7 +8054,7 @@ static void raid5_status(struct seq_file *seq, struct mddev *mddev)
 	seq_printf (seq, "]");
 }
 
-static void print_raid5_conf (struct r5conf *conf)
+static void print_raid5_conf(struct r5conf *conf)
 {
 	struct md_rdev *rdev;
 	int i;
@@ -8068,15 +8068,13 @@ static void print_raid5_conf (struct r5conf *conf)
 	       conf->raid_disks,
 	       conf->raid_disks - conf->mddev->degraded);
 
-	rcu_read_lock();
 	for (i = 0; i < conf->raid_disks; i++) {
-		rdev = rcu_dereference(conf->disks[i].rdev);
+		rdev = conf->disks[i].rdev;
 		if (rdev)
 			pr_debug(" disk %d, o:%d, dev:%pg\n",
 			       i, !test_bit(Faulty, &rdev->flags),
 			       rdev->bdev);
 	}
-	rcu_read_unlock();
 }
 
 static int raid5_spare_active(struct mddev *mddev)