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bcache: use delayed kworker fo asynchronous devices registration

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This patch changes the asynchronous registration kworker to a delayed
kworker. There is probability queue_work() queues the async registration
kworker to the same CPU (even though very little), then the process
which writing sysfs interface to reigster bcache device may won't return
immeidately. queue_delayed_work() in this patch will delay 10 jiffies
before insert the kworker to run queue, which makes sure the registering
process may always returns to user space in time.

Fixes: 9e23ccf8f0 ("bcache: asynchronous devices registration")
Signed-off-by: Coly Li <colyli@suse.de>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Coly Li 2020-06-15 00:53:32 +08:00 committed by Jens Axboe
parent dcacbc1242
commit ee4a36f414
1 changed files with 8 additions and 6 deletions
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14
drivers/md/bcache/super.c
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@ -19,6 +19,7 @@
#include <linux/genhd.h>
#include <linux/idr.h>
#include <linux/kthread.h>
#include <linux/workqueue.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/reboot.h>
@ -2380,7 +2381,7 @@ static bool bch_is_open(struct block_device *bdev)
}
struct async_reg_args {
struct work_struct reg_work;
struct delayed_work reg_work;
char *path;
struct cache_sb *sb;
struct cache_sb_disk *sb_disk;
@ -2391,7 +2392,7 @@ static void register_bdev_worker(struct work_struct *work)
{
int fail = false;
struct async_reg_args *args =
container_of(work, struct async_reg_args, reg_work);
container_of(work, struct async_reg_args, reg_work.work);
struct cached_dev *dc;
dc = kzalloc(sizeof(*dc), GFP_KERNEL);
@ -2421,7 +2422,7 @@ static void register_cache_worker(struct work_struct *work)
{
int fail = false;
struct async_reg_args *args =
container_of(work, struct async_reg_args, reg_work);
container_of(work, struct async_reg_args, reg_work.work);
struct cache *ca;
ca = kzalloc(sizeof(*ca), GFP_KERNEL);
@ -2449,11 +2450,12 @@ out:
static void register_device_aync(struct async_reg_args *args)
{
if (SB_IS_BDEV(args->sb))
INIT_WORK(&args->reg_work, register_bdev_worker);
INIT_DELAYED_WORK(&args->reg_work, register_bdev_worker);
else
INIT_WORK(&args->reg_work, register_cache_worker);
INIT_DELAYED_WORK(&args->reg_work, register_cache_worker);
queue_work(system_wq, &args->reg_work);
/* 10 jiffies is enough for a delay */
queue_delayed_work(system_wq, &args->reg_work, 10);
}
static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,