dax, xfs, ext4: compile out iomap-dax paths in the FS_DAX=n case

Tetsuo reports:

  fs/built-in.o: In function `xfs_file_iomap_end':
  xfs_iomap.c:(.text+0xe0ef9): undefined reference to `put_dax'
  fs/built-in.o: In function `xfs_file_iomap_begin':
  xfs_iomap.c:(.text+0xe1a7f): undefined reference to `dax_get_by_host'
  make: *** [vmlinux] Error 1
  $ grep DAX .config
  CONFIG_DAX=m
  # CONFIG_DEV_DAX is not set
  # CONFIG_FS_DAX is not set

When FS_DAX=n we can/must throw away the dax code in filesystems.
Implement 'fs_' versions of dax_get_by_host() and put_dax() that are
nops in the FS_DAX=n case.

Cc: <linux-xfs@vger.kernel.org>
Cc: <linux-ext4@vger.kernel.org>
Cc: Jan Kara <jack@suse.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Fixes: ddbbcf0e1263 ("block, dax: move 'select DAX' from BLOCK to FS_DAX")
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 26d77f9f8c12e69f48bc6cc1c4f47bb6fab27ebd..2dcbd56988843ccdfb017c9b14ca8f5b05a31b62 100644 (file)
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -817,7 +817,7 @@ static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
        iomap->bdev = bdev;
        iomap->offset = (u64)first_block << blkbits;
        if (blk_queue_dax(bdev->bd_queue))
-               iomap->dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);
+               iomap->dax_dev = fs_dax_get_by_host(bdev->bd_disk->disk_name);
        else
                iomap->dax_dev = NULL;
 
@@ -841,7 +841,7 @@ static int
 ext2_iomap_end(struct inode *inode, loff_t offset, loff_t length,
                ssize_t written, unsigned flags, struct iomap *iomap)
 {
-       put_dax(iomap->dax_dev);
+       fs_put_dax(iomap->dax_dev);
        if (iomap->type == IOMAP_MAPPED &&
            written < length &&
            (flags & IOMAP_WRITE))

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 5834c4d76be80969125a9c2d56309e990ba07e84..1bd0bfa547f6deee46d8dfe039625ed1736d14ed 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3412,7 +3412,7 @@ retry:
        bdev = inode->i_sb->s_bdev;
        iomap->bdev = bdev;
        if (blk_queue_dax(bdev->bd_queue))
-               iomap->dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);
+               iomap->dax_dev = fs_dax_get_by_host(bdev->bd_disk->disk_name);
        else
                iomap->dax_dev = NULL;
        iomap->offset = first_block << blkbits;
@@ -3447,7 +3447,7 @@ static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length,
        int blkbits = inode->i_blkbits;
        bool truncate = false;
 
-       put_dax(iomap->dax_dev);
+       fs_put_dax(iomap->dax_dev);
        if (!(flags & IOMAP_WRITE) || (flags & IOMAP_FAULT))
                return 0;
 

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index a63f61c256bdc54f0a8ee6088702dbd5e91ee9aa..94e5bdf7304cff79c9ad7784013520776e3086f8 100644 (file)
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -1068,7 +1068,7 @@ xfs_file_iomap_begin(
        /* optionally associate a dax device with the iomap bdev */
        bdev = iomap->bdev;
        if (blk_queue_dax(bdev->bd_queue))
-               iomap->dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);
+               iomap->dax_dev = fs_dax_get_by_host(bdev->bd_disk->disk_name);
        else
                iomap->dax_dev = NULL;
 
@@ -1149,7 +1149,7 @@ xfs_file_iomap_end(
        unsigned                flags,
        struct iomap            *iomap)
 {
-       put_dax(iomap->dax_dev);
+       fs_put_dax(iomap->dax_dev);
        if ((flags & IOMAP_WRITE) && iomap->type == IOMAP_DELALLOC)
                return xfs_file_iomap_end_delalloc(XFS_I(inode), offset,
                                length, written, iomap);

diff --git a/include/linux/dax.h b/include/linux/dax.h
index 00ebac854bb79f16ed5b04d74c6dafa641de0bb7..5ec1f6c47716d6fe7c750456cef81cc0e321b1bc 100644 (file)
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -18,6 +18,20 @@ struct dax_operations {
                        void **, pfn_t *);
 };
 
+#if IS_ENABLED(CONFIG_DAX)
+struct dax_device *dax_get_by_host(const char *host);
+void put_dax(struct dax_device *dax_dev);
+#else
+static inline struct dax_device *dax_get_by_host(const char *host)
+{
+       return NULL;
+}
+
+static inline void put_dax(struct dax_device *dax_dev)
+{
+}
+#endif
+
 int bdev_dax_pgoff(struct block_device *, sector_t, size_t, pgoff_t *pgoff);
 #if IS_ENABLED(CONFIG_FS_DAX)
 int __bdev_dax_supported(struct super_block *sb, int blocksize);
@@ -25,23 +39,29 @@ static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
 {
        return __bdev_dax_supported(sb, blocksize);
 }
+
+static inline struct dax_device *fs_dax_get_by_host(const char *host)
+{
+       return dax_get_by_host(host);
+}
+
+static inline void fs_put_dax(struct dax_device *dax_dev)
+{
+       put_dax(dax_dev);
+}
+
 #else
 static inline int bdev_dax_supported(struct super_block *sb, int blocksize)
 {
        return -EOPNOTSUPP;
 }
-#endif
 
-#if IS_ENABLED(CONFIG_DAX)
-struct dax_device *dax_get_by_host(const char *host);
-void put_dax(struct dax_device *dax_dev);
-#else
-static inline struct dax_device *dax_get_by_host(const char *host)
+static inline struct dax_device *fs_dax_get_by_host(const char *host)
 {
        return NULL;
 }
 
-static inline void put_dax(struct dax_device *dax_dev)
+static inline void fs_put_dax(struct dax_device *dax_dev)
 {
 }
 #endif