bdi: make inode_to_bdi() inline

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.

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

v2: Fixed typo in description as suggested by Jan.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/fs/block_dev.c b/fs/block_dev.c
index e545cbfbe5b2f25cf800d7b556f385592a84fd93..f04c873a7365c1b50c88cf7116135597213d64bb 100644 (file)
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -547,7 +547,8 @@ 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)
 {
@@ -688,11 +689,6 @@ 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 a69d2e10d51454d6b34c787af699b169a03dcf13..34d1cb854fc183a0ae5d9a6c7b0e4dcb94f6a24f 100644 (file)
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -78,22 +78,6 @@ 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 5e39f7a8efedf40775a4c953b82059aceeb00868..785782034e8634604ca3909edffba6119f0b66b6 100644 (file)
--- 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 1ef63900243c58bc4813168ea6fefc21a1bff852..ce100b87fba32441966a4b82f1b62a3d5aea291b 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2240,7 +2240,13 @@ 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 ff85ecb7d6a103c94d4da80c340f24b919c259e3..b0707d1b1d38d2aa8c20fa2bb5c734c7979a58b0 100644 (file)
--- 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;