block: don't take lock on changing ra_pages

There's no need to take queue_lock or kernel_lock when modifying
bdi->ra_pages. So remove them. Also remove out of date comment for
queue_max_sectors_store().

Signed-off-by: Wu Fengguang <wfg@linux.intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 0 insertions, 2 deletions

diff --git a/block/ioctl.c b/block/ioctl.c
index d03985b04d67..0f22e629b13c 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -323,9 +323,7 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
                 bdi = blk_get_backing_dev_info(bdev);
                 if (bdi == NULL)
                         return -ENOTTY;
-                lock_kernel();
                 bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
-                unlock_kernel();
                 return 0;
         case BLKBSZSET:
                 /* set the logical block size */