[PATCH v5 07/11] loop: Factor out configuring loop from status

Martijn Coenen
2020-05-13T13:39:08Z

Factor out this code into a separate function, so it can be reused by
other code more easily.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martijn Coenen <maco@android.com>
---
drivers/block/loop.c | 117 +++++++++++++++++++++++++------------------
1 file changed, 67 insertions(+), 50 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index e281a9f03d96..6a4c0ba225ca 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1251,75 +1251,43 @@ static int loop_clr_fd(struct loop_device *lo)
return __loop_clr_fd(lo, false);
}

+/**
+ * loop_set_status_from_info - configure device from loop_info
+ * @lo: struct loop_device to configure
+ * @info: struct loop_info64 to configure the device with
+ *
+ * Configures the loop device parameters according to the passed
+ * in loop_info64 configuration.
+ */
static int
-loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
+loop_set_status_from_info(struct loop_device *lo,
+ const struct loop_info64 *info)
{
int err;
struct loop_func_table *xfer;
kuid_t uid = current_uid();
- struct block_device *bdev;
- bool partscan = false;
- bool size_changed = false;
-
- err = mutex_lock_killable(&loop_ctl_mutex);
- if (err)
- return err;
- if (lo->lo_encrypt_key_size &&
- !uid_eq(lo->lo_key_owner, uid) &&
- !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;
- }
-
- if (lo->lo_offset != info->lo_offset ||
- lo->lo_sizelimit != info->lo_sizelimit) {
- size_changed = true;
- sync_blockdev(lo->lo_device);
- kill_bdev(lo->lo_device);
- }

- /* I/O need to be drained during transfer transition */
- blk_mq_freeze_queue(lo->lo_queue);
-
- if (size_changed && lo->lo_device->bd_inode->i_mapping->nrpages) {
- /* If any pages were dirtied after kill_bdev(), try again */
- err = -EAGAIN;
- pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n",
- __func__, lo->lo_number, lo->lo_file_name,
- lo->lo_device->bd_inode->i_mapping->nrpages);
- goto out_unfreeze;
- }
+ if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE)
+ return -EINVAL;

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

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

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

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

lo->lo_offset = info->lo_offset;
lo->lo_sizelimit = info->lo_sizelimit;
@@ -1346,6 +1314,55 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
lo->lo_key_owner = uid;
}

+ return 0;
+}
+
+static int
+loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
+{
+ int err;
+ struct block_device *bdev;
+ kuid_t uid = current_uid();
+ bool partscan = false;
+ bool size_changed = false;
+
+ err = mutex_lock_killable(&loop_ctl_mutex);
+ if (err)
+ return err;
+ if (lo->lo_encrypt_key_size &&
+ !uid_eq(lo->lo_key_owner, uid) &&
+ !capable(CAP_SYS_ADMIN)) {
+ err = -EPERM;
+ goto out_unlock;
+ }
+ if (lo->lo_state != Lo_bound) {
+ err = -ENXIO;
+ goto out_unlock;
+ }
+
+ if (lo->lo_offset != info->lo_offset ||
+ lo->lo_sizelimit != info->lo_sizelimit) {
+ size_changed = true;
+ sync_blockdev(lo->lo_device);
+ kill_bdev(lo->lo_device);
+ }
+
+ /* I/O need to be drained during transfer transition */
+ blk_mq_freeze_queue(lo->lo_queue);
+
+ if (size_changed && lo->lo_device->bd_inode->i_mapping->nrpages) {
+ /* If any pages were dirtied after kill_bdev(), try again */
+ err = -EAGAIN;
+ pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n",
+ __func__, lo->lo_number, lo->lo_file_name,
+ lo->lo_device->bd_inode->i_mapping->nrpages);
+ goto out_unfreeze;
+ }
+
+ err = loop_set_status_from_info(lo, info);
+ if (err)
+ goto out_unfreeze;
+
if (size_changed) {
loff_t new_size = get_size(lo->lo_offset, lo->lo_sizelimit,
lo->lo_backing_file);
--
2.26.2.645.ge9eca65c58-goog