[PATCH v4 6/6] block: Update blkdev_dax_capable() for consistency

Toshi Kani
2016-05-10T16:33:59Z

blkdev_dax_capable() is similar to bdev_dax_supported(), but needs
to remain as a separate interface for checking dax capability of
a raw block device.

Rename and relocate blkdev_dax_capable() to keep them maintained
consistently, and call bdev_direct_access() for the dax capability
check.

There is no change in the behavior.

Link: https://lkml.org/lkml/2016/5/9/950
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@fb.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jan Kara <jack@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Boaz Harrosh <boaz@plexistor.com>
---
block/ioctl.c | 30 ------------------------------
fs/block_dev.c | 39 +++++++++++++++++++++++++++++++++++++--
include/linux/blkdev.h | 1 +
include/linux/fs.h | 8 --------
4 files changed, 38 insertions(+), 40 deletions(-)

diff --git a/block/ioctl.c b/block/ioctl.c
index 4ff1f92..7eeda07 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -4,7 +4,6 @@
#include <linux/gfp.h>
#include <linux/blkpg.h>
#include <linux/hdreg.h>
-#include <linux/badblocks.h>
#include <linux/backing-dev.h>
#include <linux/fs.h>
#include <linux/blktrace_api.h>
@@ -407,35 +406,6 @@ static inline int is_unrecognized_ioctl(int ret)
ret == -ENOIOCTLCMD;
}

-#ifdef CONFIG_FS_DAX
-bool blkdev_dax_capable(struct block_device *bdev)
-{
- struct gendisk *disk = bdev->bd_disk;
-
- if (!disk->fops->direct_access)
- return false;
-
- /*
- * If the partition is not aligned on a page boundary, we can't
- * do dax I/O to it.
- */
- if ((bdev->bd_part->start_sect % (PAGE_SIZE / 512))
- || (bdev->bd_part->nr_sects % (PAGE_SIZE / 512)))
- return false;
-
- /*
- * If the device has known bad blocks, force all I/O through the
- * driver / page cache.
- *
- * TODO: support finer grained dax error handling
- */
- if (disk->bb && disk->bb->count)
- return false;
-
- return true;
-}
-#endif
-
static int blkdev_flushbuf(struct block_device *bdev, fmode_t mode,
unsigned cmd, unsigned long arg)
{
diff --git a/fs/block_dev.c b/fs/block_dev.c
index db55638..5d79093 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -29,6 +29,7 @@
#include <linux/log2.h>
#include <linux/cleancache.h>
#include <linux/dax.h>
+#include <linux/badblocks.h>
#include <asm/uaccess.h>
#include "internal.h"

@@ -554,6 +555,40 @@ int bdev_dax_supported(struct super_block *sb, int blocksize)
}
EXPORT_SYMBOL_GPL(bdev_dax_supported);

+/**
+ * bdev_dax_capable() - Return if the raw device is capable for dax
+ * @bdev: The device for raw block device access
+ */
+bool bdev_dax_capable(struct block_device *bdev)
+{
+ struct gendisk *disk = bdev->bd_disk;
+ struct blk_dax_ctl dax = {
+ .size = PAGE_SIZE,
+ };
+
+ if (!IS_ENABLED(CONFIG_FS_DAX))
+ return false;
+
+ dax.sector = 0;
+ if (bdev_direct_access(bdev, &dax) < 0)
+ return false;
+
+ dax.sector = bdev->bd_part->nr_sects - (PAGE_SIZE / 512);
+ if (bdev_direct_access(bdev, &dax) < 0)
+ return false;
+
+ /*
+ * If the device has known bad blocks, force all I/O through the
+ * driver / page cache.
+ *
+ * TODO: support finer grained dax error handling
+ */
+ if (disk->bb && disk->bb->count)
+ return false;
+
+ return true;
+}
+
/*
* pseudo-fs
*/
@@ -1295,7 +1330,7 @@ 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);
- if (!blkdev_dax_capable(bdev))
+ if (!bdev_dax_capable(bdev))
bdev->bd_inode->i_flags &= ~S_DAX;
}

@@ -1332,7 +1367,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
goto out_clear;
}
bd_set_size(bdev, (loff_t)bdev->bd_part->nr_sects << 9);
- if (!blkdev_dax_capable(bdev))
+ if (!bdev_dax_capable(bdev))
bdev->bd_inode->i_flags &= ~S_DAX;
}
} else {
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 71231a5..27cbefe 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1689,6 +1689,7 @@ extern int bdev_write_page(struct block_device *, sector_t, struct page *,
struct writeback_control *);
extern long bdev_direct_access(struct block_device *, struct blk_dax_ctl *);
extern int bdev_dax_supported(struct super_block *, int);
+extern bool bdev_dax_capable(struct block_device *);
#else /* CONFIG_BLOCK */

struct block_device;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 70e61b5..8363a10 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2320,14 +2320,6 @@ 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 *);
-#ifdef CONFIG_FS_DAX
-extern bool blkdev_dax_capable(struct block_device *bdev);
-#else
-static inline bool blkdev_dax_capable(struct block_device *bdev)
-{
- return false;
-}
-#endif

extern struct super_block *blockdev_superblock;