xfs: kill off l_sectbb_mask

There remains only one user of the l_sectbb_mask field in the log
structure.  Just kill it off and compute the mask where needed from
the power-of-2 sector size.

(Only update from last post is to accomodate the changes in the
previous patch in the series.)
Signed-off-by: Alex Elder <aelder@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/xfs_log.c

@@ -1089,7 +1089,6 @@ xlog_alloc_log(xfs_mount_t	*mp,
 		}
 	}
 	log->l_sectBBsize = 1 << log2_size;
-	log->l_sectbb_mask = log->l_sectBBsize - 1;
 
 	xlog_get_iclog_buffer_size(mp, log);
 

fs/xfs/xfs_log_priv.h

@@ -396,9 +396,7 @@ typedef struct log {
 	struct xfs_buf_cancel	**l_buf_cancel_table;
 	int			l_iclog_hsize;  /* size of iclog header */
 	int			l_iclog_heads;  /* # of iclog header sectors */
-	uint			l_sectBBsize;   /* sector size in BBs */
-	uint			l_sectbb_mask;  /* sector size (in BBs)
-						 * alignment mask */
+	uint			l_sectBBsize;   /* sector size in BBs (2^n) */
 	int			l_iclog_size;	/* size of log in bytes */
 	int			l_iclog_size_log; /* log power size of log */
 	int			l_iclog_bufs;	/* number of iclog buffers */

fs/xfs/xfs_log_recover.c

@@ -121,6 +121,10 @@ xlog_put_bp(
 	xfs_buf_free(bp);
 }
 
+/*
+ * Return the address of the start of the given block number's data
+ * in a log buffer.  The buffer covers a log sector-aligned region.
+ */
 STATIC xfs_caddr_t
 xlog_align(
 	xlog_t		*log,
@@ -128,14 +132,14 @@ xlog_align(
 	int		nbblks,
 	xfs_buf_t	*bp)
 {
+	xfs_daddr_t	offset;
 	xfs_caddr_t	ptr;
 
-	if (log->l_sectBBsize == 1)
-		return XFS_BUF_PTR(bp);
+	offset = blk_no & ((xfs_daddr_t) log->l_sectBBsize - 1);
+	ptr = XFS_BUF_PTR(bp) + BBTOB(offset);
+
+	ASSERT(ptr + BBTOB(nbblks) <= XFS_BUF_PTR(bp) + XFS_BUF_SIZE(bp));
 
-	ptr = XFS_BUF_PTR(bp) + BBTOB((int)blk_no & log->l_sectbb_mask);
-	ASSERT(XFS_BUF_SIZE(bp) >=
-		BBTOB(nbblks + (blk_no & log->l_sectbb_mask)));
 	return ptr;
 }