xfs: simplify buffer pinning

Get rid of the xfs_buf_pin/xfs_buf_unpin/xfs_buf_ispin helpers and opencode
them in their only callers, just like we did for the inode pinning a while
ago.  Also remove duplicate trace points - the bufitem tracepoints cover
all the information that is present in a buffer tracepoint.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

fs/xfs/linux-2.6/xfs_buf.c

@@ -896,36 +896,6 @@ xfs_buf_unlock(
 	trace_xfs_buf_unlock(bp, _RET_IP_);
 }
 
-
-/*
- *	Pinning Buffer Storage in Memory
- *	Ensure that no attempt to force a buffer to disk will succeed.
- */
-void
-xfs_buf_pin(
-	xfs_buf_t		*bp)
-{
-	trace_xfs_buf_pin(bp, _RET_IP_);
-	atomic_inc(&bp->b_pin_count);
-}
-
-void
-xfs_buf_unpin(
-	xfs_buf_t		*bp)
-{
-	trace_xfs_buf_unpin(bp, _RET_IP_);
-
-	if (atomic_dec_and_test(&bp->b_pin_count))
-		wake_up_all(&bp->b_waiters);
-}
-
-int
-xfs_buf_ispin(
-	xfs_buf_t		*bp)
-{
-	return atomic_read(&bp->b_pin_count);
-}
-
 STATIC void
 xfs_buf_wait_unpin(
 	xfs_buf_t		*bp)
@@ -1803,7 +1773,7 @@ xfs_buf_delwri_split(
 		trace_xfs_buf_delwri_split(bp, _RET_IP_);
 		ASSERT(bp->b_flags & XBF_DELWRI);
 
-		if (!xfs_buf_ispin(bp) && !xfs_buf_cond_lock(bp)) {
+		if (!XFS_BUF_ISPINNED(bp) && !xfs_buf_cond_lock(bp)) {
 			if (!force &&
 			    time_before(jiffies, bp->b_queuetime + age)) {
 				xfs_buf_unlock(bp);

fs/xfs/linux-2.6/xfs_buf.h

@@ -258,11 +258,6 @@ static inline int xfs_buf_geterror(xfs_buf_t *bp)
 /* Buffer Utility Routines */
 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
 
-/* Pinning Buffer Storage in Memory */
-extern void xfs_buf_pin(xfs_buf_t *);
-extern void xfs_buf_unpin(xfs_buf_t *);
-extern int xfs_buf_ispin(xfs_buf_t *);
-
 /* Delayed Write Buffer Routines */
 extern void xfs_buf_delwri_dequeue(xfs_buf_t *);
 extern void xfs_buf_delwri_promote(xfs_buf_t *);
@@ -351,7 +346,7 @@ extern void xfs_buf_terminate(void);
 #define XFS_BUF_SET_VTYPE(bp, type)		do { } while (0)
 #define XFS_BUF_SET_REF(bp, ref)		do { } while (0)
 
-#define XFS_BUF_ISPINNED(bp)	xfs_buf_ispin(bp)
+#define XFS_BUF_ISPINNED(bp)	atomic_read(&((bp)->b_pin_count))
 
 #define XFS_BUF_VALUSEMA(bp)	xfs_buf_lock_value(bp)
 #define XFS_BUF_CPSEMA(bp)	(xfs_buf_cond_lock(bp) == 0)
@@ -370,8 +365,6 @@ static inline void xfs_buf_relse(xfs_buf_t *bp)
 	xfs_buf_rele(bp);
 }
 
-#define xfs_bpin(bp)		xfs_buf_pin(bp)
-#define xfs_bunpin(bp)		xfs_buf_unpin(bp)
 #define xfs_biodone(bp)		xfs_buf_ioend(bp, 0)
 
 #define xfs_biomove(bp, off, len, data, rw) \

fs/xfs/linux-2.6/xfs_trace.h

@@ -317,8 +317,6 @@ DEFINE_BUF_EVENT(xfs_buf_init);
 DEFINE_BUF_EVENT(xfs_buf_free);
 DEFINE_BUF_EVENT(xfs_buf_hold);
 DEFINE_BUF_EVENT(xfs_buf_rele);
-DEFINE_BUF_EVENT(xfs_buf_pin);
-DEFINE_BUF_EVENT(xfs_buf_unpin);
 DEFINE_BUF_EVENT(xfs_buf_iodone);
 DEFINE_BUF_EVENT(xfs_buf_iorequest);
 DEFINE_BUF_EVENT(xfs_buf_bawrite);

fs/xfs/xfs_buf_item.c

@@ -359,14 +359,13 @@ xfs_buf_item_format(
 
 /*
  * This is called to pin the buffer associated with the buf log item in memory
- * so it cannot be written out.  Simply call bpin() on the buffer to do this.
+ * so it cannot be written out.
  *
  * We also always take a reference to the buffer log item here so that the bli
  * is held while the item is pinned in memory. This means that we can
  * unconditionally drop the reference count a transaction holds when the
  * transaction is completed.
  */
-
 STATIC void
 xfs_buf_item_pin(
 	struct xfs_log_item	*lip)
@@ -378,15 +377,15 @@ xfs_buf_item_pin(
 	ASSERT((bip->bli_flags & XFS_BLI_LOGGED) ||
 	       (bip->bli_flags & XFS_BLI_STALE));
 
-	atomic_inc(&bip->bli_refcount);
 	trace_xfs_buf_item_pin(bip);
-	xfs_bpin(bip->bli_buf);
+
+	atomic_inc(&bip->bli_refcount);
+	atomic_inc(&bip->bli_buf->b_pin_count);
 }
 
 /*
  * This is called to unpin the buffer associated with the buf log
  * item which was previously pinned with a call to xfs_buf_item_pin().
- * Just call bunpin() on the buffer to do this.
  *
  * Also drop the reference to the buf item for the current transaction.
  * If the XFS_BLI_STALE flag is set and we are the last reference,
@@ -414,7 +413,9 @@ xfs_buf_item_unpin(
 	trace_xfs_buf_item_unpin(bip);
 
 	freed = atomic_dec_and_test(&bip->bli_refcount);
-	xfs_bunpin(bp);
+
+	if (atomic_dec_and_test(&bp->b_pin_count))
+		wake_up_all(&bp->b_waiters);
 
 	if (freed && stale) {
 		ASSERT(bip->bli_flags & XFS_BLI_STALE);