The following commit has been merged into the locking/core branch of tip:
Commit-ID: 175b1a60e8805617d74aefe17ce0d3a32eceb55c
Gitweb:
https://git.kernel.org/tip/175b1a60e8805617d74aefe17ce0d3a32eceb55c
Author: Peter Zijlstra <pet...@infradead.org>
AuthorDate: Thu, 10 Dec 2020 11:16:34 +01:00
Committer: Peter Zijlstra <pet...@infradead.org>
CommitterDate: Thu, 14 Jan 2021 11:20:17 +01:00
locking/lockdep: Clean up check_redundant() a bit
In preparation for adding an TRACE_IRQFLAGS dependent skip function to
check_redundant(), move it below the TRACE_IRQFLAGS #ifdef.
While there, provide a stub function to reduce #ifdef usage.
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
---
kernel/locking/lockdep.c | 91 +++++++++++++++++++++------------------
1 file changed, 49 insertions(+), 42 deletions(-)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index f50f026..f2ae8a6 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2130,46 +2130,6 @@ check_noncircular(struct held_lock *src, struct
held_lock *target,
return ret;
}
-#ifdef CONFIG_LOCKDEP_SMALL
-/*
- * Check that the dependency graph starting at <src> can lead to
- * <target> or not. If it can, <src> -> <target> dependency is already
- * in the graph.
- *
- * Return BFS_RMATCH if it does, or BFS_RMATCH if it does not, return BFS_E* if
- * any error appears in the bfs search.
- */
-static noinline enum bfs_result
-check_redundant(struct held_lock *src, struct held_lock *target)
-{
- enum bfs_result ret;
- struct lock_list *target_entry;
- struct lock_list src_entry;
-
- bfs_init_root(&src_entry, src);
- /*
- * Special setup for check_redundant().
- *
- * To report redundant, we need to find a strong dependency path that
- * is equal to or stronger than <src> -> <target>. So if <src> is E,
- * we need to let __bfs() only search for a path starting at a -(E*)->,
- * we achieve this by setting the initial node's ->only_xr to true in
- * that case. And if <prev> is S, we set initial ->only_xr to false
- * because both -(S*)-> (equal) and -(E*)-> (stronger) are redundant.
- */
- src_entry.only_xr = src->read == 0;
-
- debug_atomic_inc(nr_redundant_checks);
-
- ret = check_path(target, &src_entry, hlock_equal, NULL, &target_entry);
-
- if (ret == BFS_RMATCH)
- debug_atomic_inc(nr_redundant);
-
- return ret;
-}
-#endif
-
#ifdef CONFIG_TRACE_IRQFLAGS
/*
@@ -2706,6 +2666,55 @@ static inline int check_irq_usage(struct task_struct
*curr,
}
#endif /* CONFIG_TRACE_IRQFLAGS */
+#ifdef CONFIG_LOCKDEP_SMALL
+/*
+ * Check that the dependency graph starting at <src> can lead to
+ * <target> or not. If it can, <src> -> <target> dependency is already
+ * in the graph.
+ *
+ * Return BFS_RMATCH if it does, or BFS_RMATCH if it does not, return BFS_E* if
+ * any error appears in the bfs search.
+ */
+static noinline enum bfs_result
+check_redundant(struct held_lock *src, struct held_lock *target)
+{
+ enum bfs_result ret;
+ struct lock_list *target_entry;
+ struct lock_list src_entry;
+
+ bfs_init_root(&src_entry, src);
+ /*
+ * Special setup for check_redundant().
+ *
+ * To report redundant, we need to find a strong dependency path that
+ * is equal to or stronger than <src> -> <target>. So if <src> is E,
+ * we need to let __bfs() only search for a path starting at a -(E*)->,
+ * we achieve this by setting the initial node's ->only_xr to true in
+ * that case. And if <prev> is S, we set initial ->only_xr to false
+ * because both -(S*)-> (equal) and -(E*)-> (stronger) are redundant.
+ */
+ src_entry.only_xr = src->read == 0;
+
+ debug_atomic_inc(nr_redundant_checks);
+
+ ret = check_path(target, &src_entry, hlock_equal, NULL, &target_entry);
+
+ if (ret == BFS_RMATCH)
+ debug_atomic_inc(nr_redundant);
+
+ return ret;
+}
+
+#else
+
+static inline enum bfs_result
+check_redundant(struct held_lock *src, struct held_lock *target)
+{
+ return BFS_RNOMATCH;
+}
+
+#endif
+
static void inc_chains(int irq_context)
{
if (irq_context & LOCK_CHAIN_HARDIRQ_CONTEXT)
@@ -2926,7 +2935,6 @@ check_prev_add(struct task_struct *curr, struct held_lock
*prev,
}
}
-#ifdef CONFIG_LOCKDEP_SMALL
/*
* Is the <prev> -> <next> link redundant?
*/
@@ -2935,7 +2943,6 @@ check_prev_add(struct task_struct *curr, struct held_lock
*prev,
return 0;
else if (ret == BFS_RMATCH)
return 2;
-#endif
if (!*trace) {
*trace = save_trace();
