[PATCH 09/15] loop: Push loop_ctl_mutex down to loop_set_status()

Jan Kara
2018-10-10T17:25:48Z

Push loop_ctl_mutex down to loop_set_status(). We will need this to be
able to call loop_reread_partitions() without loop_ctl_mutex.

Signed-off-by: Jan Kara <jack@suse.cz>
---
drivers/block/loop.c | 51 +++++++++++++++++++++++++--------------------------
1 file changed, 25 insertions(+), 26 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index cb4eeff91238..5661489d11a7 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1142,46 +1142,55 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
struct loop_func_table *xfer;
kuid_t uid = current_uid();

+ err = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
+ if (err)
+ return err;
if (lo->lo_encrypt_key_size &&
!uid_eq(lo->lo_key_owner, uid) &&
- !capable(CAP_SYS_ADMIN))
- return -EPERM;
- if (lo->lo_state != Lo_bound)
- return -ENXIO;
- if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE)
- return -EINVAL;
+ !capable(CAP_SYS_ADMIN)) {
+ err = -EPERM;
+ goto out_unlock;
+ }
+ if (lo->lo_state != Lo_bound) {
+ err = -ENXIO;
+ goto out_unlock;
+ }
+ if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE) {
+ err = -EINVAL;
+ goto out_unlock;
+ }

/* I/O need to be drained during transfer transition */
blk_mq_freeze_queue(lo->lo_queue);

err = loop_release_xfer(lo);
if (err)
- goto exit;
+ goto out_unfreeze;

if (info->lo_encrypt_type) {
unsigned int type = info->lo_encrypt_type;

if (type >= MAX_LO_CRYPT) {
err = -EINVAL;
- goto exit;
+ goto out_unfreeze;
}
xfer = xfer_funcs[type];
if (xfer == NULL) {
err = -EINVAL;
- goto exit;
+ goto out_unfreeze;
}
} else
xfer = NULL;

err = loop_init_xfer(lo, xfer, info);
if (err)
- goto exit;
+ goto out_unfreeze;

if (lo->lo_offset != info->lo_offset ||
lo->lo_sizelimit != info->lo_sizelimit) {
if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit)) {
err = -EFBIG;
- goto exit;
+ goto out_unfreeze;
}
}

@@ -1213,7 +1222,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
/* update dio if lo_offset or transfer is changed */
__loop_update_dio(lo, lo->use_dio);

- exit:
+out_unfreeze:
blk_mq_unfreeze_queue(lo->lo_queue);

if (!err && (info->lo_flags & LO_FLAGS_PARTSCAN) &&
@@ -1222,6 +1231,8 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;
loop_reread_partitions(lo, lo->lo_device);
}
+out_unlock:
+ mutex_unlock(&loop_ctl_mutex);

return err;
}
@@ -1468,12 +1479,8 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode,
case LOOP_SET_STATUS:
err = -EPERM;
if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) {
- err = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
- if (err)
- return err;
err = loop_set_status_old(lo,
(struct loop_info __user *)arg);
- mutex_unlock(&loop_ctl_mutex);
}
break;
case LOOP_GET_STATUS:
@@ -1481,12 +1488,8 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode,
case LOOP_SET_STATUS64:
err = -EPERM;
if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) {
- err = mutex_lock_killable_nested(&loop_ctl_mutex, 1);
- if (err)
- return err;
err = loop_set_status64(lo,
(struct loop_info64 __user *) arg);
- mutex_unlock(&loop_ctl_mutex);
}
break;
case LOOP_GET_STATUS64:
@@ -1631,12 +1634,8 @@ static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode,

switch(cmd) {
case LOOP_SET_STATUS:
- err = mutex_lock_killable(&loop_ctl_mutex);
- if (!err) {
- err = loop_set_status_compat(lo,
- (const struct compat_loop_info __user *)arg);
- mutex_unlock(&loop_ctl_mutex);
- }
+ err = loop_set_status_compat(lo,
+ (const struct compat_loop_info __user *)arg);
break;
case LOOP_GET_STATUS:
err = loop_get_status_compat(lo,
--
2.16.4