xfs: make use of the l_targ field in struct xlog

Use the slightly shorter way to get at the buftarg for the log device
wherever we can in the log and log recovery code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/xfs_log.c

@@ -927,7 +927,7 @@ xfs_log_unmount_write(xfs_mount_t *mp)
 	 * Or, if we are doing a forced umount (typically because of IO errors).
 	 */
 	if (mp->m_flags & XFS_MOUNT_NORECOVERY ||
-	    xfs_readonly_buftarg(log->l_mp->m_logdev_targp)) {
+	    xfs_readonly_buftarg(log->l_targ)) {
 		ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
 		return 0;
 	}
@@ -1442,7 +1442,7 @@ xlog_alloc_log(
 	 * having set it up properly.
 	 */
 	error = -ENOMEM;
-	bp = xfs_buf_alloc(mp->m_logdev_targp, XFS_BUF_DADDR_NULL,
+	bp = xfs_buf_alloc(log->l_targ, XFS_BUF_DADDR_NULL,
 			   BTOBB(log->l_iclog_size), XBF_NO_IOACCT);
 	if (!bp)
 		goto out_free_log;
@@ -1912,7 +1912,7 @@ xlog_sync(
 	 * synchronously here; for an internal log we can simply use the block
 	 * layer state machine for preflushes.
 	 */
-	if (log->l_mp->m_logdev_targp != log->l_mp->m_ddev_targp || split) {
+	if (log->l_targ != log->l_mp->m_ddev_targp || split) {
 		xfs_blkdev_issue_flush(log->l_mp->m_ddev_targp);
 		need_flush = false;
 	}

fs/xfs/xfs_log_recover.c

@@ -134,7 +134,7 @@ xlog_get_bp(
 		nbblks += log->l_sectBBsize;
 	nbblks = round_up(nbblks, log->l_sectBBsize);
 
-	bp = xfs_buf_get_uncached(log->l_mp->m_logdev_targp, nbblks, 0);
+	bp = xfs_buf_get_uncached(log->l_targ, nbblks, 0);
 	if (bp)
 		xfs_buf_unlock(bp);
 	return bp;
@@ -1505,7 +1505,7 @@ xlog_find_tail(
 	 * But... if the -device- itself is readonly, just skip this.
 	 * We can't recover this device anyway, so it won't matter.
 	 */
-	if (!xfs_readonly_buftarg(log->l_mp->m_logdev_targp))
+	if (!xfs_readonly_buftarg(log->l_targ))
 		error = xlog_clear_stale_blocks(log, tail_lsn);
 
 done: