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.
Implement a new internal workqueue flag, __WQ_USER_OWNED_LOCKDEP, to
indicate that the user will set up the workqueue lockdep map using the
new function alloc_workqueue_lockdep_map. Also add helper macro
alloc_ordered_workqueue_lockdep_map.
v2:
- Add alloc_workqueue_lockdep_map (Tejun)
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Lai Jiangshan <jiangshanlai@xxxxxxxxx>
Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
---
include/linux/workqueue.h | 25 +++++++++++++++++++++++++
kernel/workqueue.c | 28 ++++++++++++++++++++++++++++
2 files changed, 53 insertions(+)
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index d9968bfc8eac..1707870ef7c5 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -406,6 +406,7 @@ enum wq_flags {
__WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */
__WQ_ORDERED = 1 << 17, /* internal: workqueue is ordered */
__WQ_LEGACY = 1 << 18, /* internal: create*_workqueue() */
+ __WQ_USER_OWNED_LOCKDEP = 1 << 19, /* internal: workqueue has user owned lockdep map */
/* BH wq only allows the following flags */
__WQ_BH_ALLOWS = WQ_BH | WQ_HIGHPRI,
@@ -507,6 +508,30 @@ 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-defined 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, ...);
+
+#define alloc_ordered_workqueue_lockdep_map(fmt, flags, lockdep_map, args...) \
+ alloc_workqueue_lockdep_map(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, lockdep_map, ##args)
+#endif
+
/**
* alloc_ordered_workqueue - allocate an ordered workqueue
* @fmt: printf format for the name of the workqueue
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index b3fa4d044f69..e1361dedbe06 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -4795,11 +4795,17 @@ static void wq_init_lockdep(struct workqueue_struct *wq)
static void wq_unregister_lockdep(struct workqueue_struct *wq)
{
+ if (wq->flags & __WQ_USER_OWNED_LOCKDEP)
+ return;
+
lockdep_unregister_key(&wq->key);
}
static void wq_free_lockdep(struct workqueue_struct *wq)
{
+ if (wq->flags & __WQ_USER_OWNED_LOCKDEP)
+ return;
+
if (wq->lock_name != wq->name)
kfree(wq->lock_name);
}
@@ -5792,6 +5798,28 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
}
EXPORT_SYMBOL_GPL(alloc_workqueue);
+#ifdef CONFIG_LOCKDEP
+__printf(1, 5)
+struct workqueue_struct *
+alloc_workqueue_lockdep_map(const char *fmt, unsigned int flags,
+ int max_active, struct lockdep_map *lockdep_map, ...)
+{
+ struct workqueue_struct *wq;
+ va_list args;
+
+ va_start(args, lockdep_map);
+ wq = __alloc_workqueue(fmt, flags | __WQ_USER_OWNED_LOCKDEP, max_active, args);
+ va_end(args);
+ if (!wq)
+ return NULL;
+
+ wq->lockdep_map = lockdep_map;
+
+ return wq;
+}
+EXPORT_SYMBOL_GPL(alloc_workqueue_lockdep_map);
+#endif
+
static bool pwq_busy(struct pool_workqueue *pwq)
{
int i;
--
2.34.1
