xfs: add a xfs_inode_buftarg helper

Add a new xfs_inode_buftarg helper that gets the data I/O buftarg for a
given inode.  Replace the existing xfs_find_bdev_for_inode and
xfs_find_daxdev_for_inode helpers with this new general one and cleanup
some of the callers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/xfs_aops.c

@@ -30,32 +30,6 @@ XFS_WPC(struct iomap_writepage_ctx *ctx)
 	return container_of(ctx, struct xfs_writepage_ctx, ctx);
 }
 
-struct block_device *
-xfs_find_bdev_for_inode(
-	struct inode		*inode)
-{
-	struct xfs_inode	*ip = XFS_I(inode);
-	struct xfs_mount	*mp = ip->i_mount;
-
-	if (XFS_IS_REALTIME_INODE(ip))
-		return mp->m_rtdev_targp->bt_bdev;
-	else
-		return mp->m_ddev_targp->bt_bdev;
-}
-
-struct dax_device *
-xfs_find_daxdev_for_inode(
-	struct inode		*inode)
-{
-	struct xfs_inode	*ip = XFS_I(inode);
-	struct xfs_mount	*mp = ip->i_mount;
-
-	if (XFS_IS_REALTIME_INODE(ip))
-		return mp->m_rtdev_targp->bt_daxdev;
-	else
-		return mp->m_ddev_targp->bt_daxdev;
-}
-
 /*
  * Fast and loose check if this write could update the on-disk inode size.
  */
@@ -609,9 +583,11 @@ xfs_dax_writepages(
 	struct address_space	*mapping,
 	struct writeback_control *wbc)
 {
-	xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED);
+	struct xfs_inode	*ip = XFS_I(mapping->host);
+
+	xfs_iflags_clear(ip, XFS_ITRUNCATED);
 	return dax_writeback_mapping_range(mapping,
-			xfs_find_bdev_for_inode(mapping->host), wbc);
+			xfs_inode_buftarg(ip)->bt_bdev, wbc);
 }
 
 STATIC sector_t
@@ -661,7 +637,7 @@ xfs_iomap_swapfile_activate(
 	struct file			*swap_file,
 	sector_t			*span)
 {
-	sis->bdev = xfs_find_bdev_for_inode(file_inode(swap_file));
+	sis->bdev = xfs_inode_buftarg(XFS_I(file_inode(swap_file)))->bt_bdev;
 	return iomap_swapfile_activate(sis, swap_file, span,
 			&xfs_read_iomap_ops);
 }

fs/xfs/xfs_aops.h

@@ -11,7 +11,4 @@ extern const struct address_space_operations xfs_dax_aops;
 
 int	xfs_setfilesize(struct xfs_inode *ip, xfs_off_t offset, size_t size);
 
-extern struct block_device *xfs_find_bdev_for_inode(struct inode *);
-extern struct dax_device *xfs_find_daxdev_for_inode(struct inode *);
-
 #endif /* __XFS_AOPS_H__ */

fs/xfs/xfs_bmap_util.c

@@ -58,10 +58,11 @@ xfs_zero_extent(
 	xfs_off_t		count_fsb)
 {
 	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_buftarg	*target = xfs_inode_buftarg(ip);
 	xfs_daddr_t		sector = xfs_fsb_to_db(ip, start_fsb);
 	sector_t		block = XFS_BB_TO_FSBT(mp, sector);
 
-	return blkdev_issue_zeroout(xfs_find_bdev_for_inode(VFS_I(ip)),
+	return blkdev_issue_zeroout(target->bt_bdev,
 		block << (mp->m_super->s_blocksize_bits - 9),
 		count_fsb << (mp->m_super->s_blocksize_bits - 9),
 		GFP_NOFS, 0);

fs/xfs/xfs_file.c

@@ -1229,22 +1229,22 @@ static const struct vm_operations_struct xfs_file_vm_ops = {
 
 STATIC int
 xfs_file_mmap(
-	struct file	*filp,
+	struct file		*file,
 	struct vm_area_struct	*vma)
 {
-	struct dax_device 	*dax_dev;
+	struct inode		*inode = file_inode(file);
+	struct xfs_buftarg	*target = xfs_inode_buftarg(XFS_I(inode));
 
-	dax_dev = xfs_find_daxdev_for_inode(file_inode(filp));
 	/*
 	 * We don't support synchronous mappings for non-DAX files and
 	 * for DAX files if underneath dax_device is not synchronous.
 	 */
-	if (!daxdev_mapping_supported(vma, dax_dev))
+	if (!daxdev_mapping_supported(vma, target->bt_daxdev))
 		return -EOPNOTSUPP;
 
-	file_accessed(filp);
+	file_accessed(file);
 	vma->vm_ops = &xfs_file_vm_ops;
-	if (IS_DAX(file_inode(filp)))
+	if (IS_DAX(inode))
 		vma->vm_flags |= VM_HUGEPAGE;
 	return 0;
 }

fs/xfs/xfs_inode.h

@@ -219,6 +219,13 @@ static inline bool xfs_inode_has_cow_data(struct xfs_inode *ip)
 	return ip->i_cowfp && ip->i_cowfp->if_bytes;
 }
 
+/*
+ * Return the buftarg used for data allocations on a given inode.
+ */
+#define xfs_inode_buftarg(ip) \
+	(XFS_IS_REALTIME_INODE(ip) ? \
+		(ip)->i_mount->m_rtdev_targp : (ip)->i_mount->m_ddev_targp)
+
 /*
  * In-core inode flags.
  */

fs/xfs/xfs_ioctl.c

@@ -1311,10 +1311,9 @@ xfs_ioctl_setattr_dax_invalidate(
 	 * have to check the device for dax support or flush pagecache.
 	 */
 	if (fa->fsx_xflags & FS_XFLAG_DAX) {
-		if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)))
-			return -EINVAL;
-		if (!bdev_dax_supported(xfs_find_bdev_for_inode(VFS_I(ip)),
-				sb->s_blocksize))
+		struct xfs_buftarg	*target = xfs_inode_buftarg(ip);
+
+		if (!bdev_dax_supported(target->bt_bdev, sb->s_blocksize))
 			return -EINVAL;
 	}
 

fs/xfs/xfs_iomap.c

@@ -57,6 +57,7 @@ xfs_bmbt_to_iomap(
 	u16			flags)
 {
 	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_buftarg	*target = xfs_inode_buftarg(ip);
 
 	if (unlikely(!xfs_valid_startblock(ip, imap->br_startblock)))
 		return xfs_alert_fsblock_zero(ip, imap);
@@ -77,8 +78,8 @@ xfs_bmbt_to_iomap(
 	}
 	iomap->offset = XFS_FSB_TO_B(mp, imap->br_startoff);
 	iomap->length = XFS_FSB_TO_B(mp, imap->br_blockcount);
-	iomap->bdev = xfs_find_bdev_for_inode(VFS_I(ip));
-	iomap->dax_dev = xfs_find_daxdev_for_inode(VFS_I(ip));
+	iomap->bdev = target->bt_bdev;
+	iomap->dax_dev = target->bt_daxdev;
 	iomap->flags = flags;
 
 	if (xfs_ipincount(ip) &&
@@ -94,12 +95,14 @@ xfs_hole_to_iomap(
 	xfs_fileoff_t		offset_fsb,
 	xfs_fileoff_t		end_fsb)
 {
+	struct xfs_buftarg	*target = xfs_inode_buftarg(ip);
+
 	iomap->addr = IOMAP_NULL_ADDR;
 	iomap->type = IOMAP_HOLE;
 	iomap->offset = XFS_FSB_TO_B(ip->i_mount, offset_fsb);
 	iomap->length = XFS_FSB_TO_B(ip->i_mount, end_fsb - offset_fsb);
-	iomap->bdev = xfs_find_bdev_for_inode(VFS_I(ip));
-	iomap->dax_dev = xfs_find_daxdev_for_inode(VFS_I(ip));
+	iomap->bdev = target->bt_bdev;
+	iomap->dax_dev = target->bt_daxdev;
 }
 
 static inline xfs_fileoff_t

fs/xfs/xfs_iops.c

@@ -1227,7 +1227,7 @@ xfs_inode_supports_dax(
 		return false;
 
 	/* Device has to support DAX too. */
-	return xfs_find_daxdev_for_inode(VFS_I(ip)) != NULL;
+	return xfs_inode_buftarg(ip)->bt_daxdev != NULL;
 }
 
 STATIC void