xfs: simplify xfs_trans_getsb

Remove the mp argument as this function is only called in transaction
context, and open code xfs_getsb given that the function already accesses
the buffer pointer in the mount point directly.
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/libxfs/xfs_sb.c

@@ -954,7 +954,7 @@ xfs_log_sb(
 	struct xfs_trans	*tp)
 {
 	struct xfs_mount	*mp = tp->t_mountp;
-	struct xfs_buf		*bp = xfs_trans_getsb(tp, mp);
+	struct xfs_buf		*bp = xfs_trans_getsb(tp);
 
 	mp->m_sb.sb_icount = percpu_counter_sum(&mp->m_icount);
 	mp->m_sb.sb_ifree = percpu_counter_sum(&mp->m_ifree);
@@ -1084,7 +1084,7 @@ xfs_sync_sb_buf(
 	if (error)
 		return error;
 
-	bp = xfs_trans_getsb(tp, mp);
+	bp = xfs_trans_getsb(tp);
 	xfs_log_sb(tp);
 	xfs_trans_bhold(tp, bp);
 	xfs_trans_set_sync(tp);

fs/xfs/xfs_trans.c

@@ -468,7 +468,7 @@ xfs_trans_apply_sb_deltas(
 	xfs_buf_t	*bp;
 	int		whole = 0;
 
-	bp = xfs_trans_getsb(tp, tp->t_mountp);
+	bp = xfs_trans_getsb(tp);
 	sbp = bp->b_addr;
 
 	/*

fs/xfs/xfs_trans.h

@@ -209,7 +209,7 @@ xfs_trans_read_buf(
 				      flags, bpp, ops);
 }
 
-struct xfs_buf	*xfs_trans_getsb(xfs_trans_t *, struct xfs_mount *);
+struct xfs_buf	*xfs_trans_getsb(struct xfs_trans *);
 
 void		xfs_trans_brelse(xfs_trans_t *, struct xfs_buf *);
 void		xfs_trans_bjoin(xfs_trans_t *, struct xfs_buf *);

fs/xfs/xfs_trans_buf.c

@@ -166,50 +166,34 @@ xfs_trans_get_buf_map(
 }
 
 /*
- * Get and lock the superblock buffer of this file system for the
- * given transaction.
- *
- * We don't need to use incore_match() here, because the superblock
- * buffer is a private buffer which we keep a pointer to in the
- * mount structure.
+ * Get and lock the superblock buffer for the given transaction.
  */
-xfs_buf_t *
+struct xfs_buf *
 xfs_trans_getsb(
-	xfs_trans_t		*tp,
-	struct xfs_mount	*mp)
+	struct xfs_trans	*tp)
 {
-	xfs_buf_t		*bp;
-	struct xfs_buf_log_item	*bip;
+	struct xfs_buf		*bp = tp->t_mountp->m_sb_bp;
 
 	/*
-	 * Default to just trying to lock the superblock buffer
-	 * if tp is NULL.
+	 * Just increment the lock recursion count if the buffer is already
+	 * attached to this transaction.
 	 */
-	if (tp == NULL)
-		return xfs_getsb(mp);
-
-	/*
-	 * If the superblock buffer already has this transaction
-	 * pointer in its b_fsprivate2 field, then we know we already
-	 * have it locked.  In this case we just increment the lock
-	 * recursion count and return the buffer to the caller.
-	 */
-	bp = mp->m_sb_bp;
 	if (bp->b_transp == tp) {
-		bip = bp->b_log_item;
+		struct xfs_buf_log_item	*bip = bp->b_log_item;
+
 		ASSERT(bip != NULL);
 		ASSERT(atomic_read(&bip->bli_refcount) > 0);
 		bip->bli_recur++;
+
 		trace_xfs_trans_getsb_recur(bip);
-		return bp;
-	}
+	} else {
+		xfs_buf_lock(bp);
+		xfs_buf_hold(bp);
+		_xfs_trans_bjoin(tp, bp, 1);
 
-	bp = xfs_getsb(mp);
-	if (bp == NULL)
-		return NULL;
+		trace_xfs_trans_getsb(bp->b_log_item);
+	}
 
-	_xfs_trans_bjoin(tp, bp, 1);
-	trace_xfs_trans_getsb(bp->b_log_item);
 	return bp;
 }