workqueue: Add interface for user-defined workqueue lockdep map

Add an interface for a user-defined workqueue lockdep map, which is
helpful when multiple workqueues are created for the same purpose. This
also helps avoid leaking lockdep maps on each workqueue creation.

v2:
 - Add alloc_workqueue_lockdep_map (Tejun)
v3:
 - Drop __WQ_USER_OWNED_LOCKDEP (Tejun)
 - static inline alloc_ordered_workqueue_lockdep_map (Tejun)

Cc: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 4eb8f9563136..8ccbf510880b 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -507,6 +507,58 @@ void workqueue_softirq_dead(unsigned int cpu);
 __printf(1, 4) struct workqueue_struct *
 alloc_workqueue(const char *fmt, unsigned int flags, int max_active, ...);
 
+#ifdef CONFIG_LOCKDEP
+/**
+ * alloc_workqueue_lockdep_map - allocate a workqueue with user-defined lockdep_map
+ * @fmt: printf format for the name of the workqueue
+ * @flags: WQ_* flags
+ * @max_active: max in-flight work items, 0 for default
+ * @lockdep_map: user-defined lockdep_map
+ * @...: args for @fmt
+ *
+ * Same as alloc_workqueue but with the a user-define lockdep_map. Useful for
+ * workqueues created with the same purpose and to avoid leaking a lockdep_map
+ * on each workqueue creation.
+ *
+ * RETURNS:
+ * Pointer to the allocated workqueue on success, %NULL on failure.
+ */
+__printf(1, 5) struct workqueue_struct *
+alloc_workqueue_lockdep_map(const char *fmt, unsigned int flags, int max_active,
+			    struct lockdep_map *lockdep_map, ...);
+
+/**
+ * alloc_ordered_workqueue_lockdep_map - allocate an ordered workqueue with
+ * user-defined lockdep_map
+ *
+ * @fmt: printf format for the name of the workqueue
+ * @flags: WQ_* flags (only WQ_FREEZABLE and WQ_MEM_RECLAIM are meaningful)
+ * @lockdep_map: user-defined lockdep_map
+ * @args: args for @fmt
+ *
+ * Same as alloc_ordered_workqueue but with the a user-define lockdep_map.
+ * Useful for workqueues created with the same purpose and to avoid leaking a
+ * lockdep_map on each workqueue creation.
+ *
+ * RETURNS:
+ * Pointer to the allocated workqueue on success, %NULL on failure.
+ */
+__printf(1, 4) static inline struct workqueue_struct *
+alloc_ordered_workqueue_lockdep_map(const char *fmt, unsigned int flags,
+				    struct lockdep_map *lockdep_map, ...)
+{
+	struct workqueue_struct *wq;
+	va_list args;
+
+	va_start(args, lockdep_map);
+	wq = alloc_workqueue_lockdep_map(fmt, WQ_UNBOUND | __WQ_ORDERED | flags,
+					 1, lockdep_map, args);
+	va_end(args);
+
+	return wq;
+}
+#endif
+
 /**
  * alloc_ordered_workqueue - allocate an ordered workqueue
  * @fmt: printf format for the name of the workqueue