[XFS] kill BMAPI_DEVICE

There is no reason to go into the iomap machinery just to get the right
block device for an inode. Instead look at the realtime flag in the inode
and grab the right device from the mount structure.

I created a new helper, xfs_find_bdev_for_inode instead of opencoding it
because I plan to use it in other places in the future.

SGI-PV: 970240
SGI-Modid: xfs-linux-melb:xfs-kern:29680a
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Donald Douwsma <donaldd@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>

fs/xfs/linux-2.6/xfs_aops.c

@@ -107,6 +107,18 @@ xfs_page_trace(
 #define xfs_page_trace(tag, inode, page, pgoff)
 #endif
 
+STATIC struct block_device *
+xfs_find_bdev_for_inode(
+	struct xfs_inode	*ip)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+
+	if (ip->i_d.di_flags & XFS_DIFLAG_REALTIME)
+		return mp->m_rtdev_targp->bt_bdev;
+	else
+		return mp->m_ddev_targp->bt_bdev;
+}
+
 /*
  * Schedule IO completion handling on a xfsdatad if this was
  * the final hold on this ioend. If we are asked to wait,
@@ -1471,28 +1483,21 @@ xfs_vm_direct_IO(
 {
 	struct file	*file = iocb->ki_filp;
 	struct inode	*inode = file->f_mapping->host;
-	xfs_iomap_t	iomap;
-	int		maps = 1;
-	int		error;
+	struct block_device *bdev;
 	ssize_t		ret;
 
-	error = xfs_bmap(XFS_I(inode), offset, 0,
-				BMAPI_DEVICE, &iomap, &maps);
-	if (error)
-		return -error;
+	bdev = xfs_find_bdev_for_inode(XFS_I(inode));
 
 	if (rw == WRITE) {
 		iocb->private = xfs_alloc_ioend(inode, IOMAP_UNWRITTEN);
 		ret = blockdev_direct_IO_own_locking(rw, iocb, inode,
-			iomap.iomap_target->bt_bdev,
-			iov, offset, nr_segs,
+			bdev, iov, offset, nr_segs,
 			xfs_get_blocks_direct,
 			xfs_end_io_direct);
 	} else {
 		iocb->private = xfs_alloc_ioend(inode, IOMAP_READ);
 		ret = blockdev_direct_IO_no_locking(rw, iocb, inode,
-			iomap.iomap_target->bt_bdev,
-			iov, offset, nr_segs,
+			bdev, iov, offset, nr_segs,
 			xfs_get_blocks_direct,
 			xfs_end_io_direct);
 	}

fs/xfs/xfs_iomap.c

@@ -193,7 +193,7 @@ xfs_iomap(
 
 	switch (flags &
 		(BMAPI_READ | BMAPI_WRITE | BMAPI_ALLOCATE |
-		 BMAPI_UNWRITTEN | BMAPI_DEVICE)) {
+		 BMAPI_UNWRITTEN)) {
 	case BMAPI_READ:
 		xfs_iomap_enter_trace(XFS_IOMAP_READ_ENTER, io, offset, count);
 		lockmode = XFS_LCK_MAP_SHARED(mp, io);
@@ -220,13 +220,6 @@ xfs_iomap(
 		break;
 	case BMAPI_UNWRITTEN:
 		goto phase2;
-	case BMAPI_DEVICE:
-		lockmode = XFS_LCK_MAP_SHARED(mp, io);
-		iomapp->iomap_target = io->io_flags & XFS_IOCORE_RT ?
-			mp->m_rtdev_targp : mp->m_ddev_targp;
-		error = 0;
-		*niomaps = 1;
-		goto out;
 	default:
 		BUG();
 	}

fs/xfs/xfs_iomap.h

@@ -43,7 +43,6 @@ typedef enum {
 	BMAPI_MMAP = (1 << 6),		/* allocate for mmap write */
 	BMAPI_SYNC = (1 << 7),		/* sync write to flush delalloc space */
 	BMAPI_TRYLOCK = (1 << 8),	/* non-blocking request */
-	BMAPI_DEVICE = (1 << 9),	/* we only want to know the device */
 } bmapi_flags_t;