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>

1 files changed, 7 insertions, 6 deletions

diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index 60e063d96f8d..f53327a19e0d 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/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);