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loop: Get rid of loop_index_mutex 

Now that loop_ctl_mutex is global, just get rid of loop_index_mutex as
there is no good reason to keep these two separate and it just
complicates the locking.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jan Kara 2018-11-08 14:01:04 +01:00 committed by Jens Axboe
parent 967d1dc144
commit 0a42e99b58
1 changed files with 20 additions and 21 deletions
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41
drivers/block/loop.c
View File

@ -83,7 +83,6 @@
#include <linux/uaccess.h>
static DEFINE_IDR(loop_index_idr);
static DEFINE_MUTEX(loop_index_mutex);
static DEFINE_MUTEX(loop_ctl_mutex);
static int max_part;
@ -1626,9 +1625,11 @@ static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode,
static int lo_open(struct block_device *bdev, fmode_t mode)
{
struct loop_device *lo;
int err = 0;
int err;
mutex_lock(&loop_index_mutex);
err = mutex_lock_killable(&loop_ctl_mutex);
if (err)
return err;
lo = bdev->bd_disk->private_data;
if (!lo) {
err = -ENXIO;
@ -1637,7 +1638,7 @@ static int lo_open(struct block_device *bdev, fmode_t mode)
atomic_inc(&lo->lo_refcnt);
out:
mutex_unlock(&loop_index_mutex);
mutex_unlock(&loop_ctl_mutex);
return err;
}
@ -1646,12 +1647,11 @@ static void lo_release(struct gendisk *disk, fmode_t mode)
struct loop_device *lo;
int err;
mutex_lock(&loop_index_mutex);
mutex_lock(&loop_ctl_mutex);
lo = disk->private_data;
if (atomic_dec_return(&lo->lo_refcnt))
goto unlock_index;
goto out_unlock;
mutex_lock(&loop_ctl_mutex);
if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) {
/*
* In autoclear mode, stop the loop thread
@ -1659,7 +1659,7 @@ static void lo_release(struct gendisk *disk, fmode_t mode)
*/
err = loop_clr_fd(lo);
if (!err)
goto unlock_index;
return;
} else if (lo->lo_state == Lo_bound) {
/*
* Otherwise keep thread (if running) and config,
@ -1669,9 +1669,8 @@ static void lo_release(struct gendisk *disk, fmode_t mode)
blk_mq_unfreeze_queue(lo->lo_queue);
}
out_unlock:
mutex_unlock(&loop_ctl_mutex);
unlock_index:
mutex_unlock(&loop_index_mutex);
}
static const struct block_device_operations lo_fops = {
@ -1972,7 +1971,7 @@ static struct kobject *loop_probe(dev_t dev, int *part, void *data)
struct kobject *kobj;
int err;
mutex_lock(&loop_index_mutex);
mutex_lock(&loop_ctl_mutex);
err = loop_lookup(&lo, MINOR(dev) >> part_shift);
if (err < 0)
err = loop_add(&lo, MINOR(dev) >> part_shift);
@ -1980,7 +1979,7 @@ static struct kobject *loop_probe(dev_t dev, int *part, void *data)
kobj = NULL;
else
kobj = get_disk_and_module(lo->lo_disk);
mutex_unlock(&loop_index_mutex);
mutex_unlock(&loop_ctl_mutex);
*part = 0;
return kobj;
@ -1990,9 +1989,13 @@ static long loop_control_ioctl(struct file *file, unsigned int cmd,
unsigned long parm)
{
struct loop_device *lo;
int ret = -ENOSYS;
int ret;
mutex_lock(&loop_index_mutex);
ret = mutex_lock_killable(&loop_ctl_mutex);
if (ret)
return ret;
ret = -ENOSYS;
switch (cmd) {
case LOOP_CTL_ADD:
ret = loop_lookup(&lo, parm);
@ -2006,9 +2009,6 @@ static long loop_control_ioctl(struct file *file, unsigned int cmd,
ret = loop_lookup(&lo, parm);
if (ret < 0)
break;
ret = mutex_lock_killable(&loop_ctl_mutex);
if (ret)
break;
if (lo->lo_state != Lo_unbound) {
ret = -EBUSY;
mutex_unlock(&loop_ctl_mutex);
@ -2020,7 +2020,6 @@ static long loop_control_ioctl(struct file *file, unsigned int cmd,
break;
}
lo->lo_disk->private_data = NULL;
mutex_unlock(&loop_ctl_mutex);
idr_remove(&loop_index_idr, lo->lo_number);
loop_remove(lo);
break;
@ -2030,7 +2029,7 @@ static long loop_control_ioctl(struct file *file, unsigned int cmd,
break;
ret = loop_add(&lo, -1);
}
mutex_unlock(&loop_index_mutex);
mutex_unlock(&loop_ctl_mutex);
return ret;
}
@ -2114,10 +2113,10 @@ static int __init loop_init(void)
THIS_MODULE, loop_probe, NULL, NULL);
/* pre-create number of devices given by config or max_loop */
mutex_lock(&loop_index_mutex);
mutex_lock(&loop_ctl_mutex);
for (i = 0; i < nr; i++)
loop_add(&lo, i);
mutex_unlock(&loop_index_mutex);
mutex_unlock(&loop_ctl_mutex);
printk(KERN_INFO "loop: module loaded\n");
return 0;