Re: [PATCH 18/49] bdi: make inode_to_bdi() inline

Jan Kara
2015-04-20T15:47:01Z

On Mon 06-04-15 15:58:07, Tejun Heo wrote:
> Now that bdi definitions are moved to backing-dev-defs.h,
> backing-dev.h can include blkdev.h and inline inode_to_bdi() without
> worrying about introducing circular include dependency. The function
> gets called from hot paths and fairly trivial.
>
> This patch makes inode_to_bdi() and sb_is_blkdev_sb() that the
> function calls inline. blockdev_superblock and noop_backing_dev_info
> are EXPORT_GPL'd to allow the inline functions to be used from
> modules.
I somewhat hate making blockdev_superblock exported just for this. But
OK.

> While at it, maske sb_is_blkdev_sb() return bool instead of int.
^^^ make

Otherwise the patch looks good. You can add:
Reviewed-by: Jan Kara <jack@suse.cz>

Honza

> Signed-off-by: Tejun Heo <tj@kernel.org>
> Cc: Jens Axboe <axboe@kernel.dk>
> Cc: Christoph Hellwig <hch@infradead.org>
> ---
> fs/block_dev.c | 8 ++------
> fs/fs-writeback.c | 16 ----------------
> include/linux/backing-dev.h | 18 ++++++++++++++++--
> include/linux/fs.h | 8 +++++++-
> mm/backing-dev.c | 1 +
> 5 files changed, 26 insertions(+), 25 deletions(-)
>
> diff --git a/fs/block_dev.c b/fs/block_dev.c
> index e4f5f71..875d41a 100644
> --- a/fs/block_dev.c
> +++ b/fs/block_dev.c
> @@ -549,7 +549,8 @@ static struct file_system_type bd_type = {
> .kill_sb = kill_anon_super,
> };
>
> -static struct super_block *blockdev_superblock __read_mostly;
> +struct super_block *blockdev_superblock __read_mostly;
> +EXPORT_SYMBOL_GPL(blockdev_superblock);
>
> void __init bdev_cache_init(void)
> {
> @@ -690,11 +691,6 @@ static struct block_device *bd_acquire(struct inode *inode)
> return bdev;
> }
>
> -int sb_is_blkdev_sb(struct super_block *sb)
> -{
> - return sb == blockdev_superblock;
> -}
> -
> /* Call when you free inode */
>
> void bd_forget(struct inode *inode)
> diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> index 7c2f0bd..4fd264d 100644
> --- a/fs/fs-writeback.c
> +++ b/fs/fs-writeback.c
> @@ -66,22 +66,6 @@ int writeback_in_progress(struct backing_dev_info *bdi)
> }
> EXPORT_SYMBOL(writeback_in_progress);
>
> -struct backing_dev_info *inode_to_bdi(struct inode *inode)
> -{
> - struct super_block *sb;
> -
> - if (!inode)
> - return &noop_backing_dev_info;
> -
> - sb = inode->i_sb;
> -#ifdef CONFIG_BLOCK
> - if (sb_is_blkdev_sb(sb))
> - return blk_get_backing_dev_info(I_BDEV(inode));
> -#endif
> - return sb->s_bdi;
> -}
> -EXPORT_SYMBOL_GPL(inode_to_bdi);
> -
> static inline struct inode *wb_inode(struct list_head *head)
> {
> return list_entry(head, struct inode, i_wb_list);
> diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
> index 5e39f7a..7857820 100644
> --- a/include/linux/backing-dev.h
> +++ b/include/linux/backing-dev.h
> @@ -11,11 +11,10 @@
> #include <linux/kernel.h>
> #include <linux/fs.h>
> #include <linux/sched.h>
> +#include <linux/blkdev.h>
> #include <linux/writeback.h>
> #include <linux/backing-dev-defs.h>
>
> -struct backing_dev_info *inode_to_bdi(struct inode *inode);
> -
> int __must_check bdi_init(struct backing_dev_info *bdi);
> void bdi_destroy(struct backing_dev_info *bdi);
>
> @@ -149,6 +148,21 @@ extern struct backing_dev_info noop_backing_dev_info;
>
> int writeback_in_progress(struct backing_dev_info *bdi);
>
> +static inline struct backing_dev_info *inode_to_bdi(struct inode *inode)
> +{
> + struct super_block *sb;
> +
> + if (!inode)
> + return &noop_backing_dev_info;
> +
> + sb = inode->i_sb;
> +#ifdef CONFIG_BLOCK
> + if (sb_is_blkdev_sb(sb))
> + return blk_get_backing_dev_info(I_BDEV(inode));
> +#endif
> + return sb->s_bdi;
> +}
> +
> static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits)
> {
> if (bdi->congested_fn)
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index b4d71b5..ccf4b64 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -2205,7 +2205,13 @@ extern struct super_block *freeze_bdev(struct block_device *);
> extern void emergency_thaw_all(void);
> extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
> extern int fsync_bdev(struct block_device *);
> -extern int sb_is_blkdev_sb(struct super_block *sb);
> +
> +extern struct super_block *blockdev_superblock;
> +
> +static inline bool sb_is_blkdev_sb(struct super_block *sb)
> +{
> + return sb == blockdev_superblock;
> +}
> #else
> static inline void bd_forget(struct inode *inode) {}
> static inline int sync_blockdev(struct block_device *bdev) { return 0; }
> diff --git a/mm/backing-dev.c b/mm/backing-dev.c
> index ff85ecb..b0707d1 100644
> --- a/mm/backing-dev.c
> +++ b/mm/backing-dev.c
> @@ -18,6 +18,7 @@ struct backing_dev_info noop_backing_dev_info = {
> .name = "noop",
> .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
> };
> +EXPORT_SYMBOL_GPL(noop_backing_dev_info);
>
> static struct class *bdi_class;
>
> --
> 2.1.0
>
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR