[PATCH 12/13] workqueue: add worker's global worker ID

[Lai Jiangshan <laijs@cn.fujitsu.com>]

Add worker->gwid which is allocated from worker_idr.  This
will be used to record the last running worker in work->data.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
 kernel/workqueue.c          |   28 ++++++++++++++++++++++++++++
 kernel/workqueue_internal.h |    1 +
 2 files changed, 29 insertions(+), 0 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 04d1286..bc57faf 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -439,6 +439,10 @@ static atomic_t unbound_std_pool_nr_running[NR_STD_WORKER_POOLS] = {
 static DEFINE_MUTEX(worker_pool_idr_mutex);
 static DEFINE_IDR(worker_pool_idr);
 
+/* idr of all workers */
+static DEFINE_MUTEX(worker_gwid_idr_mutex);
+static DEFINE_IDR(worker_gwid_idr);
+
 static int worker_thread(void *__worker);
 
 static struct worker_pool *std_worker_pools(int cpu)
@@ -454,6 +458,26 @@ static int std_worker_pool_pri(struct worker_pool *pool)
 	return pool - std_worker_pools(pool->cpu);
 }
 
+/* allocate ID and assign it to @worker */
+static int worker_assign_gwid(struct worker *worker)
+{
+	int ret;
+
+	mutex_lock(&worker_gwid_idr_mutex);
+	idr_pre_get(&worker_gwid_idr, GFP_KERNEL);
+	ret = idr_get_new(&worker_gwid_idr, worker, &worker->gwid);
+	mutex_unlock(&worker_gwid_idr_mutex);
+
+	return ret;
+}
+
+static void free_worker_gwid(struct worker *worker)
+{
+	mutex_lock(&worker_gwid_idr_mutex);
+	idr_remove(&worker_gwid_idr, worker->gwid);
+	mutex_unlock(&worker_gwid_idr_mutex);
+}
+
 /* allocate ID and assign it to @pool */
 static int worker_pool_assign_id(struct worker_pool *pool)
 {
@@ -1814,6 +1838,9 @@ static struct worker *create_worker(struct worker_pool *pool)
 	worker->pool = pool;
 	worker->id = id;
 
+	if (worker_assign_gwid(worker))
+		goto fail;
+
 	if (pool->cpu != WORK_CPU_UNBOUND)
 		worker->task = kthread_create_on_node(worker_thread,
 					worker, cpu_to_node(pool->cpu),
@@ -1900,6 +1927,7 @@ static void destroy_worker(struct worker *worker)
 	spin_unlock_irq(&pool->lock);
 
 	kthread_stop(worker->task);
+	free_worker_gwid(worker);
 	kfree(worker);
 
 	spin_lock_irq(&pool->lock);
diff --git a/kernel/workqueue_internal.h b/kernel/workqueue_internal.h
index 328be4a..eccd50c 100644
--- a/kernel/workqueue_internal.h
+++ b/kernel/workqueue_internal.h
@@ -36,6 +36,7 @@ struct worker {
 	unsigned long		last_active;	/* L: last active timestamp */
 	unsigned int		flags;		/* X: flags */
 	int			id;		/* I: worker id */
+	int			gwid;		/* I: global worker id */
 
 	/* for rebinding worker to CPU */
 	struct work_struct	rebind_work;	/* L: for busy worker */
-- 
1.7.7.6