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Message-Id: <20230825030956.1527023-3-yukuai1@huaweicloud.com>
Date: Fri, 25 Aug 2023 11:09:51 +0800
From: Yu Kuai <yukuai1@...weicloud.com>
To: agk@...hat.com, snitzer@...nel.org, dm-devel@...hat.com,
song@...nel.org, xni@...hat.com
Cc: linux-kernel@...r.kernel.org, linux-raid@...r.kernel.org,
yukuai3@...wei.com, yukuai1@...weicloud.com, yi.zhang@...wei.com,
yangerkun@...wei.com
Subject: [PATCH -next v2 2/7] md: initialize 'writes_pending' while allocating mddev
From: Yu Kuai <yukuai3@...wei.com>
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@...wei.com>
---
drivers/md/md.c | 29 ++++++++++++-----------------
drivers/md/md.h | 1 -
drivers/md/raid1.c | 3 +--
drivers/md/raid10.c | 3 ---
drivers/md/raid5.c | 3 ---
5 files changed, 13 insertions(+), 26 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 9974cf45f9d0..e6faeb73172d 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -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);
@@ -5619,21 +5631,6 @@ 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)
{
/*
@@ -6312,7 +6309,6 @@ void md_stop(struct mddev *mddev)
*/
__md_stop_writes(mddev);
__md_stop(mddev);
- percpu_ref_exit(&mddev->writes_pending);
}
EXPORT_SYMBOL_GPL(md_stop);
@@ -7896,7 +7892,6 @@ static void md_free_disk(struct gendisk *disk)
{
struct mddev *mddev = disk->private_data;
- percpu_ref_exit(&mddev->writes_pending);
mddev_free(mddev);
}
diff --git a/drivers/md/md.h b/drivers/md/md.h
index f6b64b0e92c7..b365226a4183 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -768,7 +768,6 @@ 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);
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 4b30a1742162..95504612b7e2 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -3123,8 +3123,7 @@ 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(),
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 023413120851..a5927e98dc67 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -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))
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 4cb9c608ee19..6383723468e5 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -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));
--
2.39.2
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