md: remove redundant check of 'mddev->sync_thread'

The lifetime of sync_thread:

1) Set MD_RECOVERY_NEEDED and wake up daemon thread (by ioctl/sysfs or
   other events);
2) Daemon thread woke up, md_check_recovery() found that
   MD_RECOVERY_NEEDED is set:
   a) try to grab reconfig_mutex;
   b) set MD_RECOVERY_RUNNING;
   c) clear MD_RECOVERY_NEEDED, and then queue sync_work;
3) md_start_sync() choose sync_action, then register sync_thread;
4) md_do_sync() is done, set MD_RECOVERY_DONE and wake up daemon thread;
5) Daemon thread woke up, md_check_recovery() found that
   MD_RECOVERY_DONE is set:
   a) try to grab reconfig_mutex;
   b) unregister sync_thread;
   c) clear MD_RECOVERY_RUNNING and MD_RECOVERY_DONE;

Hence there is no such case that MD_RECOVERY_RUNNING is not set, while
sync_thread is registered.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20231228125553.2697765-2-yukuai1@huaweicloud.com

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 2266358..9b6b34a 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3339,8 +3339,7 @@ static ssize_t new_offset_store(struct md_rdev *rdev,
        if (kstrtoull(buf, 10, &new_offset) < 0)
                return -EINVAL;
 
-       if (mddev->sync_thread ||
-           test_bit(MD_RECOVERY_RUNNING,&mddev->recovery))
+       if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
                return -EBUSY;
        if (new_offset == rdev->data_offset)
                /* reset is always permitted */
@@ -4013,8 +4012,7 @@ level_store(struct mddev *mddev, const char *buf, size_t len)
         */
 
        rv = -EBUSY;
-       if (mddev->sync_thread ||
-           test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
+       if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
            mddev->reshape_position != MaxSector ||
            mddev->sysfs_active)
                goto out_unlock;
@@ -6408,7 +6406,6 @@ static int md_set_readonly(struct mddev *mddev, struct block_device *bdev)
 
        mutex_lock(&mddev->open_mutex);
        if ((mddev->pers && atomic_read(&mddev->openers) > !!bdev) ||
-           mddev->sync_thread ||
            test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) {
                pr_warn("md: %s still in use.\n",mdname(mddev));
                err = -EBUSY;
@@ -6461,7 +6458,6 @@ static int do_md_stop(struct mddev *mddev, int mode,
        mutex_lock(&mddev->open_mutex);
        if ((mddev->pers && atomic_read(&mddev->openers) > !!bdev) ||
            mddev->sysfs_active ||
-           mddev->sync_thread ||
            test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) {
                pr_warn("md: %s still in use.\n",mdname(mddev));
                mutex_unlock(&mddev->open_mutex);
@@ -7307,8 +7303,7 @@ static int update_size(struct mddev *mddev, sector_t num_sectors)
         * of each device.  If num_sectors is zero, we find the largest size
         * that fits.
         */
-       if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
-           mddev->sync_thread)
+       if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
                return -EBUSY;
        if (!md_is_rdwr(mddev))
                return -EROFS;
@@ -7345,8 +7340,7 @@ static int update_raid_disks(struct mddev *mddev, int raid_disks)
        if (raid_disks <= 0 ||
            (mddev->max_disks && raid_disks >= mddev->max_disks))
                return -EINVAL;
-       if (mddev->sync_thread ||
-           test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
+       if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
            test_bit(MD_RESYNCING_REMOTE, &mddev->recovery) ||
            mddev->reshape_position != MaxSector)
                return -EBUSY;

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 8497880..14f2cf7 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -6967,10 +6967,8 @@ raid5_store_stripe_size(struct mddev  *mddev, const char *page, size_t len)
        pr_debug("md/raid: change stripe_size from %lu to %lu\n",
                        conf->stripe_size, new);
 
-       if (mddev->sync_thread ||
-               test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
-               mddev->reshape_position != MaxSector ||
-               mddev->sysfs_active) {
+       if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
+           mddev->reshape_position != MaxSector || mddev->sysfs_active) {
                err = -EBUSY;
                goto out_unlock;
        }