[PATCH v3 2/4] xfs: refactor xfsaild_push loop into helper

[Yuto Ohnuki]

Factor the loop body of xfsaild_push() into a separate
xfsaild_process_logitem() helper to improve readability.

This is a pure code movement with no functional change. The
subsequent patch to fix a use-after-free in the AIL push path
depends on this refactoring.

Cc: <stable@xxxxxxxxxxxxxxx> # v5.9
Signed-off-by: Yuto Ohnuki <ytohnuki@xxxxxxxxxx>
---
 fs/xfs/xfs_trans_ail.c | 116 +++++++++++++++++++++++------------------
 1 file changed, 64 insertions(+), 52 deletions(-)

diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c
index 923729af4206..ac747804e1d6 100644
--- a/fs/xfs/xfs_trans_ail.c
+++ b/fs/xfs/xfs_trans_ail.c
@@ -458,6 +458,69 @@ xfs_ail_calc_push_target(
 	return target_lsn;
 }
 
+static void
+xfsaild_process_logitem(
+	struct xfs_ail		*ailp,
+	struct xfs_log_item	*lip,
+	xfs_lsn_t		lsn,
+	int			*stuck,
+	int			*flushing)
+{
+	struct xfs_mount	*mp = ailp->ail_log->l_mp;
+	int			lock_result;
+
+	/*
+	 * Note that iop_push may unlock and reacquire the AIL lock. We
+	 * rely on the AIL cursor implementation to be able to deal with
+	 * the dropped lock.
+	 */
+	lock_result = xfsaild_push_item(ailp, lip);
+	switch (lock_result) {
+	case XFS_ITEM_SUCCESS:
+		XFS_STATS_INC(mp, xs_push_ail_success);
+		trace_xfs_ail_push(lip);
+
+		ailp->ail_last_pushed_lsn = lsn;
+		break;
+
+	case XFS_ITEM_FLUSHING:
+		/*
+		 * The item or its backing buffer is already being
+		 * flushed.  The typical reason for that is that an
+		 * inode buffer is locked because we already pushed the
+		 * updates to it as part of inode clustering.
+		 *
+		 * We do not want to stop flushing just because lots
+		 * of items are already being flushed, but we need to
+		 * re-try the flushing relatively soon if most of the
+		 * AIL is being flushed.
+		 */
+		XFS_STATS_INC(mp, xs_push_ail_flushing);
+		trace_xfs_ail_flushing(lip);
+
+		(*flushing)++;
+		ailp->ail_last_pushed_lsn = lsn;
+		break;
+
+	case XFS_ITEM_PINNED:
+		XFS_STATS_INC(mp, xs_push_ail_pinned);
+		trace_xfs_ail_pinned(lip);
+
+		(*stuck)++;
+		ailp->ail_log_flush++;
+		break;
+	case XFS_ITEM_LOCKED:
+		XFS_STATS_INC(mp, xs_push_ail_locked);
+		trace_xfs_ail_locked(lip);
+
+		(*stuck)++;
+		break;
+	default:
+		ASSERT(0);
+		break;
+	}
+}
+
 static long
 xfsaild_push(
 	struct xfs_ail		*ailp)
@@ -505,62 +568,11 @@ xfsaild_push(
 
 	lsn = lip->li_lsn;
 	while ((XFS_LSN_CMP(lip->li_lsn, ailp->ail_target) <= 0)) {
-		int	lock_result;
 
 		if (test_bit(XFS_LI_FLUSHING, &lip->li_flags))
 			goto next_item;
 
-		/*
-		 * Note that iop_push may unlock and reacquire the AIL lock.  We
-		 * rely on the AIL cursor implementation to be able to deal with
-		 * the dropped lock.
-		 */
-		lock_result = xfsaild_push_item(ailp, lip);
-		switch (lock_result) {
-		case XFS_ITEM_SUCCESS:
-			XFS_STATS_INC(mp, xs_push_ail_success);
-			trace_xfs_ail_push(lip);
-
-			ailp->ail_last_pushed_lsn = lsn;
-			break;
-
-		case XFS_ITEM_FLUSHING:
-			/*
-			 * The item or its backing buffer is already being
-			 * flushed.  The typical reason for that is that an
-			 * inode buffer is locked because we already pushed the
-			 * updates to it as part of inode clustering.
-			 *
-			 * We do not want to stop flushing just because lots
-			 * of items are already being flushed, but we need to
-			 * re-try the flushing relatively soon if most of the
-			 * AIL is being flushed.
-			 */
-			XFS_STATS_INC(mp, xs_push_ail_flushing);
-			trace_xfs_ail_flushing(lip);
-
-			flushing++;
-			ailp->ail_last_pushed_lsn = lsn;
-			break;
-
-		case XFS_ITEM_PINNED:
-			XFS_STATS_INC(mp, xs_push_ail_pinned);
-			trace_xfs_ail_pinned(lip);
-
-			stuck++;
-			ailp->ail_log_flush++;
-			break;
-		case XFS_ITEM_LOCKED:
-			XFS_STATS_INC(mp, xs_push_ail_locked);
-			trace_xfs_ail_locked(lip);
-
-			stuck++;
-			break;
-		default:
-			ASSERT(0);
-			break;
-		}
-
+		xfsaild_process_logitem(ailp, lip, lsn, &stuck, &flushing);
 		count++;
 
 		/*
-- 
2.50.1




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