xfs: clean up xfs_ail_delete()

xfs_ail_delete() has a needlessly complex interface. It returns the log item
that was passed in for deletion (which the callers then assert is identical to
the one passed in), and callers of xfs_ail_delete() still need to invalidate
current traversal cursors.

Make xfs_ail_delete() return void, move the cursor invalidation inside it, and
clean up the callers just to use the log item pointer they passed in.

While cleaning up, remove the messy and unnecessary "/* ARGUSED */" comments
around all these functions.

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

fs/xfs/xfs_trans_ail.c

@@ -29,7 +29,7 @@
 #include "xfs_error.h"
 
 STATIC void xfs_ail_insert(struct xfs_ail *, xfs_log_item_t *);
-STATIC xfs_log_item_t * xfs_ail_delete(struct xfs_ail *, xfs_log_item_t *);
+STATIC void xfs_ail_delete(struct xfs_ail *, xfs_log_item_t *);
 STATIC xfs_log_item_t * xfs_ail_min(struct xfs_ail *);
 STATIC xfs_log_item_t * xfs_ail_next(struct xfs_ail *, xfs_log_item_t *);
 
@@ -468,16 +468,13 @@ xfs_trans_ail_update(
 	xfs_log_item_t	*lip,
 	xfs_lsn_t	lsn) __releases(ailp->xa_lock)
 {
-	xfs_log_item_t		*dlip = NULL;
 	xfs_log_item_t		*mlip;	/* ptr to minimum lip */
 	xfs_lsn_t		tail_lsn;
 
 	mlip = xfs_ail_min(ailp);
 
 	if (lip->li_flags & XFS_LI_IN_AIL) {
-		dlip = xfs_ail_delete(ailp, lip);
-		ASSERT(dlip == lip);
-		xfs_trans_ail_cursor_clear(ailp, dlip);
+		xfs_ail_delete(ailp, lip);
 	} else {
 		lip->li_flags |= XFS_LI_IN_AIL;
 	}
@@ -485,7 +482,7 @@ xfs_trans_ail_update(
 	lip->li_lsn = lsn;
 	xfs_ail_insert(ailp, lip);
 
-	if (mlip == dlip) {
+	if (mlip == lip) {
 		mlip = xfs_ail_min(ailp);
 		/*
 		 * It is not safe to access mlip after the AIL lock is
@@ -524,21 +521,18 @@ xfs_trans_ail_delete(
 	struct xfs_ail	*ailp,
 	xfs_log_item_t	*lip) __releases(ailp->xa_lock)
 {
-	xfs_log_item_t		*dlip;
 	xfs_log_item_t		*mlip;
 	xfs_lsn_t		tail_lsn;
 
 	if (lip->li_flags & XFS_LI_IN_AIL) {
 		mlip = xfs_ail_min(ailp);
-		dlip = xfs_ail_delete(ailp, lip);
-		ASSERT(dlip == lip);
-		xfs_trans_ail_cursor_clear(ailp, dlip);
+		xfs_ail_delete(ailp, lip);
 
 
 		lip->li_flags &= ~XFS_LI_IN_AIL;
 		lip->li_lsn = 0;
 
-		if (mlip == dlip) {
+		if (mlip == lip) {
 			mlip = xfs_ail_min(ailp);
 			/*
 			 * It is not safe to access mlip after the AIL lock
@@ -632,7 +626,6 @@ STATIC void
 xfs_ail_insert(
 	struct xfs_ail	*ailp,
 	xfs_log_item_t	*lip)
-/* ARGSUSED */
 {
 	xfs_log_item_t	*next_lip;
 
@@ -661,18 +654,14 @@ xfs_ail_insert(
 /*
  * Delete the given item from the AIL.  Return a pointer to the item.
  */
-/*ARGSUSED*/
-STATIC xfs_log_item_t *
+STATIC void
 xfs_ail_delete(
 	struct xfs_ail	*ailp,
 	xfs_log_item_t	*lip)
-/* ARGSUSED */
 {
 	xfs_ail_check(ailp, lip);
-
 	list_del(&lip->li_ail);
-
-	return lip;
+	xfs_trans_ail_cursor_clear(ailp, lip);
 }
 
 /*
@@ -682,7 +671,6 @@ xfs_ail_delete(
 STATIC xfs_log_item_t *
 xfs_ail_min(
 	struct xfs_ail	*ailp)
-/* ARGSUSED */
 {
 	if (list_empty(&ailp->xa_ail))
 		return NULL;
@@ -699,7 +687,6 @@ STATIC xfs_log_item_t *
 xfs_ail_next(
 	struct xfs_ail	*ailp,
 	xfs_log_item_t	*lip)
-/* ARGSUSED */
 {
 	if (lip->li_ail.next == &ailp->xa_ail)
 		return NULL;