From: Li Nan <[email protected]>
Changes in v4:
- patch 2, add the check of 'init', update last_events even if iostat
is disabled.
Li Nan (2):
md: Fix overflow in is_mddev_idle
md: don't account sync_io if iostats of the disk is disabled
drivers/md/md.h | 5 +++--
include/linux/blkdev.h | 2 +-
drivers/md/md.c | 11 ++++++++---
3 files changed, 12 insertions(+), 6 deletions(-)
--
2.39.2
From: Li Nan <[email protected]>
If iostats is disabled, disk_stats will not be updated and
part_stat_read_accum() only returns a constant value. In this case,
continuing to count sync_io and to check is_mddev_idle() is no longer
meaningful.
Signed-off-by: Li Nan <[email protected]>
---
drivers/md/md.h | 3 ++-
drivers/md/md.c | 4 ++++
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 1a4f976951c1..e2d03a7a858c 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -584,7 +584,8 @@ extern void mddev_unlock(struct mddev *mddev);
static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
{
- atomic64_add(nr_sectors, &bdev->bd_disk->sync_io);
+ if (blk_queue_io_stat(bdev->bd_disk->queue))
+ atomic64_add(nr_sectors, &bdev->bd_disk->sync_io);
}
static inline void md_sync_acct_bio(struct bio *bio, unsigned long nr_sectors)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index a6829ea5b560..919d6affc0ac 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8502,6 +8502,10 @@ static int is_mddev_idle(struct mddev *mddev, int init)
rcu_read_lock();
rdev_for_each_rcu(rdev, mddev) {
struct gendisk *disk = rdev->bdev->bd_disk;
+
+ if (!init && !blk_queue_io_stat(disk->queue))
+ continue;
+
curr_events =
(long long)part_stat_read_accum(disk->part0, sectors) -
atomic64_read(&disk->sync_io);
--
2.39.2
From: Li Nan <[email protected]>
UBSAN reports this problem:
UBSAN: Undefined behaviour in drivers/md/md.c:8175:15
signed integer overflow:
-2147483291 - 2072033152 cannot be represented in type 'int'
Call trace:
dump_backtrace+0x0/0x310
show_stack+0x28/0x38
dump_stack+0xec/0x15c
ubsan_epilogue+0x18/0x84
handle_overflow+0x14c/0x19c
__ubsan_handle_sub_overflow+0x34/0x44
is_mddev_idle+0x338/0x3d8
md_do_sync+0x1bb8/0x1cf8
md_thread+0x220/0x288
kthread+0x1d8/0x1e0
ret_from_fork+0x10/0x18
'curr_events' will overflow when stat accum or 'sync_io' is greater than
INT_MAX.
Fix it by changing sync_io, last_events and curr_events to 64bit.
Signed-off-by: Li Nan <[email protected]>
Reviewed-by: Yu Kuai <[email protected]>
---
drivers/md/md.h | 4 ++--
include/linux/blkdev.h | 2 +-
drivers/md/md.c | 7 ++++---
3 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/md/md.h b/drivers/md/md.h
index ade83af123a2..1a4f976951c1 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -50,7 +50,7 @@ struct md_rdev {
sector_t sectors; /* Device size (in 512bytes sectors) */
struct mddev *mddev; /* RAID array if running */
- int last_events; /* IO event timestamp */
+ long long last_events; /* IO event timestamp */
/*
* If meta_bdev is non-NULL, it means that a separate device is
@@ -584,7 +584,7 @@ extern void mddev_unlock(struct mddev *mddev);
static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
{
- atomic_add(nr_sectors, &bdev->bd_disk->sync_io);
+ atomic64_add(nr_sectors, &bdev->bd_disk->sync_io);
}
static inline void md_sync_acct_bio(struct bio *bio, unsigned long nr_sectors)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 3f8a21cd9233..d28b98adf457 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -170,7 +170,7 @@ struct gendisk {
struct list_head slave_bdevs;
#endif
struct timer_rand_state *random;
- atomic_t sync_io; /* RAID */
+ atomic64_t sync_io; /* RAID */
struct disk_events *ev;
#ifdef CONFIG_BLK_DEV_ZONED
diff --git a/drivers/md/md.c b/drivers/md/md.c
index c94373d64f2c..a6829ea5b560 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8496,14 +8496,15 @@ static int is_mddev_idle(struct mddev *mddev, int init)
{
struct md_rdev *rdev;
int idle;
- int curr_events;
+ long long curr_events;
idle = 1;
rcu_read_lock();
rdev_for_each_rcu(rdev, mddev) {
struct gendisk *disk = rdev->bdev->bd_disk;
- curr_events = (int)part_stat_read_accum(disk->part0, sectors) -
- atomic_read(&disk->sync_io);
+ curr_events =
+ (long long)part_stat_read_accum(disk->part0, sectors) -
+ atomic64_read(&disk->sync_io);
/* sync IO will cause sync_io to increase before the disk_stats
* as sync_io is counted when a request starts, and
* disk_stats is counted when it completes.
--
2.39.2
?? 2024/01/17 11:19, [email protected] д??:
> From: Li Nan <[email protected]>
>
> If iostats is disabled, disk_stats will not be updated and
> part_stat_read_accum() only returns a constant value. In this case,
> continuing to count sync_io and to check is_mddev_idle() is no longer
> meaningful.
LGTM
Reviewed-by: Yu Kuai <[email protected]>
>
> Signed-off-by: Li Nan <[email protected]>
> ---
> drivers/md/md.h | 3 ++-
> drivers/md/md.c | 4 ++++
> 2 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/md/md.h b/drivers/md/md.h
> index 1a4f976951c1..e2d03a7a858c 100644
> --- a/drivers/md/md.h
> +++ b/drivers/md/md.h
> @@ -584,7 +584,8 @@ extern void mddev_unlock(struct mddev *mddev);
>
> static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
> {
> - atomic64_add(nr_sectors, &bdev->bd_disk->sync_io);
> + if (blk_queue_io_stat(bdev->bd_disk->queue))
> + atomic64_add(nr_sectors, &bdev->bd_disk->sync_io);
> }
>
> static inline void md_sync_acct_bio(struct bio *bio, unsigned long nr_sectors)
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index a6829ea5b560..919d6affc0ac 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -8502,6 +8502,10 @@ static int is_mddev_idle(struct mddev *mddev, int init)
> rcu_read_lock();
> rdev_for_each_rcu(rdev, mddev) {
> struct gendisk *disk = rdev->bdev->bd_disk;
> +
> + if (!init && !blk_queue_io_stat(disk->queue))
> + continue;
> +
> curr_events =
> (long long)part_stat_read_accum(disk->part0, sectors) -
> atomic64_read(&disk->sync_io);
>
friendly ping ...
在 2024/1/17 11:19, [email protected] 写道:
> From: Li Nan <[email protected]>
>
> Changes in v4:
> - patch 2, add the check of 'init', update last_events even if iostat
> is disabled.
>
> Li Nan (2):
> md: Fix overflow in is_mddev_idle
> md: don't account sync_io if iostats of the disk is disabled
>
> drivers/md/md.h | 5 +++--
> include/linux/blkdev.h | 2 +-
> drivers/md/md.c | 11 ++++++++---
> 3 files changed, 12 insertions(+), 6 deletions(-)
>
--
Thanks,
Nan
On Thu, Mar 7, 2024 at 5:12 PM Li Nan <[email protected]> wrote:
>
> friendly ping ...
I am sorry that I somehow missed this (or archived it in patchwork). I think
we gonna ship this to 6.10 kernel. I will work on it later.
Thanks,
Song
On Tue, Jan 16, 2024 at 7:23 PM <[email protected]> wrote:
>
> From: Li Nan <[email protected]>
>
> Changes in v4:
> - patch 2, add the check of 'init', update last_events even if iostat
> is disabled.
>
> Li Nan (2):
> md: Fix overflow in is_mddev_idle
> md: don't account sync_io if iostats of the disk is disabled
Applied to md-6.10. Thanks!
Song