xfs: Simplify xfs_ail_min() with list_first_entry_or_null()
At xfs_ail_min(), we do check if the AIL list is empty or not before
returning the first item in it with list_empty() and list_first_entry().
This can be simplified a bit with a new list operation routine that is
the list_first_entry_or_null() which has been introduced by:
commit 6d7581e62f8be462440d7b22c6361f7c9fa4902b
list: introduce list_first_entry_or_null
v2: make xfs_ail_min() as a static inline function and move it to
xfs_trans_priv.h as per Dave Chinner's comments.
Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
diff --git a/fs/xfs/xfs_trans_priv.h b/fs/xfs/xfs_trans_priv.h
index d43b130..c52def0 100644
--- a/fs/xfs/xfs_trans_priv.h
+++ b/fs/xfs/xfs_trans_priv.h
@@ -86,6 +86,18 @@
struct xfs_ail_cursor *cur,
struct xfs_log_item **log_items, int nr_items,
xfs_lsn_t lsn) __releases(ailp->xa_lock);
+/*
+ * Return a pointer to the first item in the AIL. If the AIL is empty, then
+ * return NULL.
+ */
+static inline struct xfs_log_item *
+xfs_ail_min(
+ struct xfs_ail *ailp)
+{
+ return list_first_entry_or_null(&ailp->xa_ail, struct xfs_log_item,
+ li_ail);
+}
+
static inline void
xfs_trans_ail_update(
struct xfs_ail *ailp,