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Commit ff9ea323 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

block, bdi: an active gendisk always has a request_queue associated with it 



bdev_get_queue() returns the request_queue associated with the
specified block_device.  blk_get_backing_dev_info() makes use of
bdev_get_queue() to determine the associated bdi given a block_device.

All the callers of bdev_get_queue() including
blk_get_backing_dev_info() assume that bdev_get_queue() may return
NULL and implement NULL handling; however, bdev_get_queue() requires
the passed in block_device is opened and attached to its gendisk.
Because an active gendisk always has a valid request_queue associated
with it, bdev_get_queue() can never return NULL and neither can
blk_get_backing_dev_info().

Make it clear that neither of the two functions can return NULL and
remove NULL handling from all the callers.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent f4da8072

block/blk-core.c

+3 −7
Original line number Diff line number Diff line
@@ -83,18 +83,14 @@ void blk_queue_congestion_threshold(struct request_queue *q) 
 * @bdev:	device

 *

 * Locates the passed device's request queue and returns the address of its

 * backing_dev_info

 *

 * Will return NULL if the request queue cannot be located.

 * backing_dev_info.  This function can only be called if @bdev is opened

 * and the return value is never NULL.

 */

struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev)

{

	struct backing_dev_info *ret = NULL;

	struct request_queue *q = bdev_get_queue(bdev);



	if (q)

		ret = &q->backing_dev_info;

	return ret;

	return &q->backing_dev_info;

}

EXPORT_SYMBOL(blk_get_backing_dev_info);

block/compat_ioctl.c

+0 −4
Original line number Diff line number Diff line
@@ -709,8 +709,6 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg) 
		if (!arg)

			return -EINVAL;

		bdi = blk_get_backing_dev_info(bdev);

		if (bdi == NULL)

			return -ENOTTY;

		return compat_put_long(arg,

				       (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);

	case BLKROGET: /* compatible */
@@ -731,8 +729,6 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg) 
		if (!capable(CAP_SYS_ADMIN))

			return -EACCES;

		bdi = blk_get_backing_dev_info(bdev);

		if (bdi == NULL)

			return -ENOTTY;

		bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;

		return 0;

	case BLKGETSIZE:

block/ioctl.c

+0 −4
Original line number Diff line number Diff line
@@ -356,8 +356,6 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd, 
		if (!arg)

			return -EINVAL;

		bdi = blk_get_backing_dev_info(bdev);

		if (bdi == NULL)

			return -ENOTTY;

		return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);

	case BLKROGET:

		return put_int(arg, bdev_read_only(bdev) != 0);
@@ -386,8 +384,6 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd, 
		if(!capable(CAP_SYS_ADMIN))

			return -EACCES;

		bdi = blk_get_backing_dev_info(bdev);

		if (bdi == NULL)

			return -ENOTTY;

		bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;

		return 0;

	case BLKBSZSET:

fs/block_dev.c

+0 −2
Original line number Diff line number Diff line
@@ -1173,8 +1173,6 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) 
			if (!ret) {

				bd_set_size(bdev,(loff_t)get_capacity(disk)<<9);

				bdi = blk_get_backing_dev_info(bdev);

				if (bdi == NULL)

					bdi = &default_backing_dev_info;

				bdev_inode_switch_bdi(bdev->bd_inode, bdi);

			}

fs/btrfs/disk-io.c

+1 −1
Original line number Diff line number Diff line
@@ -1694,7 +1694,7 @@ static int btrfs_congested_fn(void *congested_data, int bdi_bits) 
		if (!device->bdev)

			continue;

		bdi = blk_get_backing_dev_info(device->bdev);

		if (bdi && bdi_congested(bdi, bdi_bits)) {

		if (bdi_congested(bdi, bdi_bits)) {

			ret = 1;

			break;

		}