4.20-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jan Kara jack@suse.cz
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: Jan Kara jack@suse.cz Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/block/loop.c | 41 ++++++++++++++++++++--------------------- 1 file changed, 20 insertions(+), 21 deletions(-)
--- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -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_ 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 *
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 *d 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 *d */ 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 *d 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 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 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 fi 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 fi 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 fi 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 fi 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;