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md: initialize 'writes_pending' while allocating mddev

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Currently 'writes_pending' is initialized in pers->run for raid1/5/10,
and it's freed while deleing mddev, instead of pers->free. pers->run can
be called multiple times before mddev is deleted, and a helper
mddev_init_writes_pending() is used to prevent 'writes_pending' to be
initialized multiple times, this usage is safe but a litter weird.

On the other hand, 'writes_pending' is only initialized for raid1/5/10,
however, it's used in common layer, for example:

array_state_store
 set_in_sync
  if (!mddev->in_sync) -> in_sync is used for all levels
   // access writes_pending

There might be some implicit dependency that I don't recognized to make
sure 'writes_pending' can only be accessed for raid1/5/10, but there are
no comments about that.

By the way, it make sense to initialize 'writes_pending' in common layer
because there are already three levels use it.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20230825030956.1527023-3-yukuai1@huaweicloud.com
This commit is contained in:
Yu Kuai 2023-08-25 11:09:51 +08:00 committed by Song Liu
parent d58eff83bd
commit b8494823e2
5 changed files with 13 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
drivers/md/md.c
View File

@ -646,6 +646,8 @@ static void active_io_release(struct percpu_ref *ref)
wake_up(&mddev->sb_wait);
}
static void no_op(struct percpu_ref *r) {}
int mddev_init(struct mddev *mddev)
{
@ -653,6 +655,15 @@ int mddev_init(struct mddev *mddev)
PERCPU_REF_ALLOW_REINIT, GFP_KERNEL))
return -ENOMEM;
if (percpu_ref_init(&mddev->writes_pending, no_op,
PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) {
percpu_ref_exit(&mddev->active_io);
return -ENOMEM;
}
/* We want to start with the refcount at zero */
percpu_ref_put(&mddev->writes_pending);
mutex_init(&mddev->open_mutex);
mutex_init(&mddev->reconfig_mutex);
mutex_init(&mddev->sync_mutex);
@ -685,6 +696,7 @@ EXPORT_SYMBOL_GPL(mddev_init);
void mddev_destroy(struct mddev *mddev)
{
percpu_ref_exit(&mddev->active_io);
percpu_ref_exit(&mddev->writes_pending);
}
EXPORT_SYMBOL_GPL(mddev_destroy);
@ -5628,21 +5640,6 @@ static void mddev_delayed_delete(struct work_struct *ws)
kobject_put(&mddev->kobj);
}
static void no_op(struct percpu_ref *r) {}
int mddev_init_writes_pending(struct mddev *mddev)
{
if (mddev->writes_pending.percpu_count_ptr)
return 0;
if (percpu_ref_init(&mddev->writes_pending, no_op,
PERCPU_REF_ALLOW_REINIT, GFP_KERNEL) < 0)
return -ENOMEM;
/* We want to start with the refcount at zero */
percpu_ref_put(&mddev->writes_pending);
return 0;
}
EXPORT_SYMBOL_GPL(mddev_init_writes_pending);
struct mddev *md_alloc(dev_t dev, char *name)
{
/*
@ -6323,7 +6320,6 @@ void md_stop(struct mddev *mddev)
*/
__md_stop_writes(mddev);
__md_stop(mddev);
percpu_ref_exit(&mddev->writes_pending);
}
EXPORT_SYMBOL_GPL(md_stop);
@ -7907,7 +7903,6 @@ static void md_free_disk(struct gendisk *disk)
{
struct mddev *mddev = disk->private_data;
percpu_ref_exit(&mddev->writes_pending);
mddev_free(mddev);
}

1
drivers/md/md.h
View File

@ -771,7 +771,6 @@ extern void md_unregister_thread(struct mddev *mddev, struct md_thread __rcu **t
extern void md_wakeup_thread(struct md_thread __rcu *thread);
extern void md_check_recovery(struct mddev *mddev);
extern void md_reap_sync_thread(struct mddev *mddev);
extern int mddev_init_writes_pending(struct mddev *mddev);
extern bool md_write_start(struct mddev *mddev, struct bio *bi);
extern void md_write_inc(struct mddev *mddev, struct bio *bi);
extern void md_write_end(struct mddev *mddev);

3
drivers/md/raid1.c
View File

@ -3122,8 +3122,7 @@ static int raid1_run(struct mddev *mddev)
mdname(mddev));
return -EIO;
}
if (mddev_init_writes_pending(mddev) < 0)
return -ENOMEM;
/*
* copy the already verified devices into our private RAID1
* bookkeeping area. [whatever we allocate in run(),

3
drivers/md/raid10.c
View File

@ -4154,9 +4154,6 @@ static int raid10_run(struct mddev *mddev)
sector_t min_offset_diff = 0;
int first = 1;
if (mddev_init_writes_pending(mddev) < 0)
return -ENOMEM;
if (mddev->private == NULL) {
conf = setup_conf(mddev);
if (IS_ERR(conf))

3
drivers/md/raid5.c
View File

@ -7778,9 +7778,6 @@ static int raid5_run(struct mddev *mddev)
long long min_offset_diff = 0;
int first = 1;
if (mddev_init_writes_pending(mddev) < 0)
return -ENOMEM;
if (mddev->recovery_cp != MaxSector)
pr_notice("md/raid:%s: not clean -- starting background reconstruction\n",
mdname(mddev));