4.4-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 | 39 ++++++++++++++++++++------------------- 1 file changed, 20 insertions(+), 19 deletions(-)
--- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -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; @@ -1571,9 +1570,11 @@ 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; @@ -1582,7 +1583,7 @@ 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; }
@@ -1591,12 +1592,11 @@ 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 @@ -1604,7 +1604,7 @@ static void lo_release(struct gendisk *d */ err = loop_clr_fd(lo); if (!err) - goto unlock_index; + return; } else { /* * Otherwise keep thread (if running) and config, @@ -1613,9 +1613,8 @@ static void lo_release(struct gendisk *d 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 = { @@ -1897,7 +1896,7 @@ 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); @@ -1905,7 +1904,7 @@ static struct kobject *loop_probe(dev_t kobj = NULL; else kobj = get_disk(lo->lo_disk); - mutex_unlock(&loop_index_mutex); + mutex_unlock(&loop_ctl_mutex);
*part = 0; return kobj; @@ -1915,9 +1914,13 @@ static long loop_control_ioctl(struct fi unsigned long parm) { struct loop_device *lo; - int ret = -ENOSYS; + int ret; + + ret = mutex_lock_killable(&loop_ctl_mutex); + if (ret) + return ret;
- mutex_lock(&loop_index_mutex); + ret = -ENOSYS; switch (cmd) { case LOOP_CTL_ADD: ret = loop_lookup(&lo, parm); @@ -1931,7 +1934,6 @@ static long loop_control_ioctl(struct fi 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); @@ -1943,7 +1945,6 @@ 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; @@ -1953,7 +1954,7 @@ 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; } @@ -2036,10 +2037,10 @@ 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;