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Commit 6a8f1d8d authored by Jan Kara's avatar Jan Kara Committed by Greg Kroah-Hartman
Browse files

loop: Get rid of loop_index_mutex 



commit 0a42e99b58a208839626465af194cfe640ef9493 upstream.

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: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7d839c10

drivers/block/loop.c

+20 −19
Original line number Diff line number Diff line
@@ -81,7 +81,6 @@ 
#include <asm/uaccess.h>



static DEFINE_IDR(loop_index_idr);

static DEFINE_MUTEX(loop_index_mutex);

static DEFINE_MUTEX(loop_ctl_mutex);



static int max_part;
@@ -1560,9 +1559,11 @@ 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;
@@ -1571,7 +1572,7 @@ 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;

}
@@ -1580,12 +1581,11 @@ 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
@@ -1593,7 +1593,7 @@ static void lo_release(struct gendisk *disk, fmode_t mode) 
		 */

		err = loop_clr_fd(lo);

		if (!err)

			goto unlock_index;

			return;

	} else {

		/*

		 * Otherwise keep thread (if running) and config,
@@ -1602,9 +1602,8 @@ static void lo_release(struct gendisk *disk, fmode_t mode) 
		loop_flush(lo);

	}



out_unlock:

	mutex_unlock(&loop_ctl_mutex);

unlock_index:

	mutex_unlock(&loop_index_mutex);

}



static const struct block_device_operations lo_fops = {
@@ -1890,7 +1889,7 @@ 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);
@@ -1898,7 +1897,7 @@ static struct kobject *loop_probe(dev_t dev, int *part, void *data) 
		kobj = NULL;

	else

		kobj = get_disk(lo->lo_disk);

	mutex_unlock(&loop_index_mutex);

	mutex_unlock(&loop_ctl_mutex);



	*part = 0;

	return kobj;
@@ -1908,9 +1907,13 @@ 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);
@@ -1924,7 +1927,6 @@ static long loop_control_ioctl(struct file *file, unsigned int cmd, 
		ret = loop_lookup(&lo, parm);

		if (ret < 0)

			break;

		mutex_lock(&loop_ctl_mutex);

		if (lo->lo_state != Lo_unbound) {

			ret = -EBUSY;

			mutex_unlock(&loop_ctl_mutex);
@@ -1936,7 +1938,6 @@ 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;
@@ -1946,7 +1947,7 @@ 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;

}
@@ -2029,10 +2030,10 @@ 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;