loop: Only change blocksize when needed.
Return early in loop_set_block_size() if the requested block size is
identical to the one we already have; this avoids expensive calls to
freeze the block queue.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martijn Coenen <maco@android.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 739b372..93b8d60 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1539,16 +1539,16 @@ static int loop_set_block_size(struct loop_device *lo, unsigned long arg)
if (arg < 512 || arg > PAGE_SIZE || !is_power_of_2(arg))
return -EINVAL;
- if (lo->lo_queue->limits.logical_block_size != arg) {
- sync_blockdev(lo->lo_device);
- kill_bdev(lo->lo_device);
- }
+ if (lo->lo_queue->limits.logical_block_size == arg)
+ return 0;
+
+ sync_blockdev(lo->lo_device);
+ kill_bdev(lo->lo_device);
blk_mq_freeze_queue(lo->lo_queue);
/* kill_bdev should have truncated all the pages */
- if (lo->lo_queue->limits.logical_block_size != arg &&
- lo->lo_device->bd_inode->i_mapping->nrpages) {
+ if (lo->lo_device->bd_inode->i_mapping->nrpages) {
err = -EAGAIN;
pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n",
__func__, lo->lo_number, lo->lo_file_name,
