4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Greg Kroah-Hartman <[email protected]> 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 <[email protected]> Reported-by: Jan Kara <[email protected]> Cc: Jens Axboe <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/block/loop.c | 39 +++++++++++++++++++-------------------- 1 file changed, 19 insertions(+), 20 deletions(-) --- 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_compat_ioctl(struct block_ 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 @@ static int lo_open(struct block_device * atomic_inc(&lo->lo_refcnt); out: - mutex_unlock(&loop_ctl_mutex); + mutex_unlock(&loop_index_mutex); return err; } @@ -1581,11 +1580,12 @@ static void lo_release(struct gendisk *d 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 @@ static void lo_release(struct gendisk *d */ err = loop_clr_fd(lo); if (!err) - return; + goto unlock_index; } else { /* * Otherwise keep thread (if running) and config, @@ -1602,8 +1602,9 @@ 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 = { @@ -1889,7 +1890,7 @@ static struct kobject *loop_probe(dev_t 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 @@ static struct kobject *loop_probe(dev_t 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 @@ static long loop_control_ioctl(struct fi unsigned long parm) { struct loop_device *lo; - int ret; - - ret = mutex_lock_killable(&loop_ctl_mutex); - if (ret) - return ret; + int ret = -ENOSYS; - ret = -ENOSYS; + mutex_lock(&loop_index_mutex); switch (cmd) { case LOOP_CTL_ADD: ret = loop_lookup(&lo, parm); @@ -1927,6 +1924,7 @@ 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); @@ -1938,6 +1936,7 @@ 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; @@ -1947,7 +1946,7 @@ static long loop_control_ioctl(struct fi break; ret = loop_add(&lo, -1); } - mutex_unlock(&loop_ctl_mutex); + mutex_unlock(&loop_index_mutex); return ret; } @@ -2030,10 +2029,10 @@ 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_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;
