Revert "loop: Get rid of loop_index_mutex"
This reverts commit 6a8f1d8d701462937ce01a3f2219af5435372af7 which is
commit 0a42e99b58a208839626465af194cfe640ef9493 upstream.
It does not work properly in the 4.9.y tree and causes more problems
than it fixes, so revert it.
Reported-by: Thomas Lindroth <thomas.lindroth@gmail.com>
Reported-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 4af7b08..3fa04ce 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -81,6 +81,7 @@
#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;
@@ -1559,11 +1560,9 @@
static int lo_open(struct block_device *bdev, fmode_t mode)
{
struct loop_device *lo;
- int err;
+ int err = 0;
- err = mutex_lock_killable(&loop_ctl_mutex);
- if (err)
- return err;
+ mutex_lock(&loop_index_mutex);
lo = bdev->bd_disk->private_data;
if (!lo) {
err = -ENXIO;
@@ -1572,7 +1571,7 @@
atomic_inc(&lo->lo_refcnt);
out:
- mutex_unlock(&loop_ctl_mutex);
+ mutex_unlock(&loop_index_mutex);
return err;
}
@@ -1581,11 +1580,12 @@
struct loop_device *lo;
int err;
- mutex_lock(&loop_ctl_mutex);
+ mutex_lock(&loop_index_mutex);
lo = disk->private_data;
if (atomic_dec_return(&lo->lo_refcnt))
- goto out_unlock;
+ goto unlock_index;
+ mutex_lock(&loop_ctl_mutex);
if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) {
/*
* In autoclear mode, stop the loop thread
@@ -1593,7 +1593,7 @@
*/
err = loop_clr_fd(lo);
if (!err)
- return;
+ goto unlock_index;
} else {
/*
* Otherwise keep thread (if running) and config,
@@ -1602,8 +1602,9 @@
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 = {
@@ -1889,7 +1890,7 @@
struct kobject *kobj;
int err;
- mutex_lock(&loop_ctl_mutex);
+ mutex_lock(&loop_index_mutex);
err = loop_lookup(&lo, MINOR(dev) >> part_shift);
if (err < 0)
err = loop_add(&lo, MINOR(dev) >> part_shift);
@@ -1897,7 +1898,7 @@
kobj = NULL;
else
kobj = get_disk(lo->lo_disk);
- mutex_unlock(&loop_ctl_mutex);
+ mutex_unlock(&loop_index_mutex);
*part = 0;
return kobj;
@@ -1907,13 +1908,9 @@
unsigned long parm)
{
struct loop_device *lo;
- int ret;
+ int ret = -ENOSYS;
- ret = mutex_lock_killable(&loop_ctl_mutex);
- if (ret)
- return ret;
-
- ret = -ENOSYS;
+ mutex_lock(&loop_index_mutex);
switch (cmd) {
case LOOP_CTL_ADD:
ret = loop_lookup(&lo, parm);
@@ -1927,6 +1924,7 @@
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);
@@ -1938,6 +1936,7 @@
break;
}
lo->lo_disk->private_data = NULL;
+ mutex_unlock(&loop_ctl_mutex);
idr_remove(&loop_index_idr, lo->lo_number);
loop_remove(lo);
break;
@@ -1947,7 +1946,7 @@
break;
ret = loop_add(&lo, -1);
}
- mutex_unlock(&loop_ctl_mutex);
+ mutex_unlock(&loop_index_mutex);
return ret;
}
@@ -2030,10 +2029,10 @@
THIS_MODULE, loop_probe, NULL, NULL);
/* pre-create number of devices given by config or max_loop */
- mutex_lock(&loop_ctl_mutex);
+ mutex_lock(&loop_index_mutex);
for (i = 0; i < nr; i++)
loop_add(&lo, i);
- mutex_unlock(&loop_ctl_mutex);
+ mutex_unlock(&loop_index_mutex);
printk(KERN_INFO "loop: module loaded\n");
return 0;