From: Tejun Heo Date: Sun, 7 Sep 2014 23:03:56 +0000 (+0900) Subject: block, bdi: an active gendisk always has a request_queue associated with it X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=ff9ea323816dc1c8ac7144afd4eab3ac97704430;p=openwrt%2Fstaging%2Fblogic.git 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: Tejun Heo Cc: Chris Mason Cc: Dave Chinner Signed-off-by: Jens Axboe --- diff --git a/block/blk-core.c b/block/blk-core.c index 93603e6ff479..817446175489 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -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); diff --git a/block/compat_ioctl.c b/block/compat_ioctl.c index 18b282ce361e..f678c733df40 100644 --- a/block/compat_ioctl.c +++ b/block/compat_ioctl.c @@ -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: diff --git a/block/ioctl.c b/block/ioctl.c index d6cda8147c91..6c7bf903742f 100644 --- a/block/ioctl.c +++ b/block/ioctl.c @@ -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: diff --git a/fs/block_dev.c b/fs/block_dev.c index 6d7274619bf9..d3251eca6429 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -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); } diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index d0ed9e664f7d..39ff591ae1b4 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -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; } diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index cd7b8ca9b064..497fcde381d7 100644 --- a/fs/xfs/xfs_buf.c +++ b/fs/xfs/xfs_buf.c @@ -1678,8 +1678,6 @@ xfs_alloc_buftarg( btp->bt_dev = bdev->bd_dev; btp->bt_bdev = bdev; btp->bt_bdi = blk_get_backing_dev_info(bdev); - if (!btp->bt_bdi) - goto error; if (xfs_setsize_buftarg_early(btp, bdev)) goto error; diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 518b46555b80..e267bf0db559 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -865,7 +865,7 @@ extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *, static inline struct request_queue *bdev_get_queue(struct block_device *bdev) { - return bdev->bd_disk->queue; + return bdev->bd_disk->queue; /* this is never NULL */ } /*