1 files changed, 52 insertions, 44 deletions

diff --git a/fs/io-wq.c b/fs/io-wq.c
index bb7f161bb19c..9595616ccaa3 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -76,6 +76,7 @@ struct io_wqe_acct {
 	unsigned max_workers;
 	int index;
 	atomic_t nr_running;
+	raw_spinlock_t lock;
 	struct io_wq_work_list work_list;
 	unsigned long flags;
 };
@@ -224,12 +225,12 @@ static void io_worker_exit(struct io_worker *worker)
 	if (worker->flags & IO_WORKER_F_FREE)
 		hlist_nulls_del_rcu(&worker->nulls_node);
 	list_del_rcu(&worker->all_list);
-	preempt_disable();
+	raw_spin_unlock(&wqe->lock);
 	io_wqe_dec_running(worker);
 	worker->flags = 0;
+	preempt_disable();
 	current->flags &= ~PF_IO_WORKER;
 	preempt_enable();
-	raw_spin_unlock(&wqe->lock);
 
 	kfree_rcu(worker, rcu);
 	io_worker_ref_put(wqe->wq);
@@ -385,7 +386,6 @@ fail:
 }
 
 static void io_wqe_dec_running(struct io_worker *worker)
-	__must_hold(wqe->lock)
 {
 	struct io_wqe_acct *acct = io_wqe_get_acct(worker);
 	struct io_wqe *wqe = worker->wqe;
@@ -393,13 +393,18 @@ static void io_wqe_dec_running(struct io_worker *worker)
 	if (!(worker->flags & IO_WORKER_F_UP))
 		return;
 
-	if (atomic_dec_and_test(&acct->nr_running) && io_acct_run_queue(acct)) {
-		atomic_inc(&acct->nr_running);
-		atomic_inc(&wqe->wq->worker_refs);
+	if (!atomic_dec_and_test(&acct->nr_running))
+		return;
+	raw_spin_lock(&wqe->lock);
+	if (!io_acct_run_queue(acct)) {
 		raw_spin_unlock(&wqe->lock);
-		io_queue_worker_create(worker, acct, create_worker_cb);
-		raw_spin_lock(&wqe->lock);
+		return;
 	}
+
+	raw_spin_unlock(&wqe->lock);
+	atomic_inc(&acct->nr_running);
+	atomic_inc(&wqe->wq->worker_refs);
+	io_queue_worker_create(worker, acct, create_worker_cb);
 }
 
 /*
@@ -407,11 +412,12 @@ static void io_wqe_dec_running(struct io_worker *worker)
  * it's currently on the freelist
  */
 static void __io_worker_busy(struct io_wqe *wqe, struct io_worker *worker)
-	__must_hold(wqe->lock)
 {
 	if (worker->flags & IO_WORKER_F_FREE) {
 		worker->flags &= ~IO_WORKER_F_FREE;
+		raw_spin_lock(&wqe->lock);
 		hlist_nulls_del_init_rcu(&worker->nulls_node);
+		raw_spin_unlock(&wqe->lock);
 	}
 }
 
@@ -456,7 +462,7 @@ static bool io_wait_on_hash(struct io_wqe *wqe, unsigned int hash)
 
 static struct io_wq_work *io_get_next_work(struct io_wqe_acct *acct,
 					   struct io_worker *worker)
-	__must_hold(wqe->lock)
+	__must_hold(acct->lock)
 {
 	struct io_wq_work_node *node, *prev;
 	struct io_wq_work *work, *tail;
@@ -498,9 +504,9 @@ static struct io_wq_work *io_get_next_work(struct io_wqe_acct *acct,
 		 * work being added and clearing the stalled bit.
 		 */
 		set_bit(IO_ACCT_STALLED_BIT, &acct->flags);
-		raw_spin_unlock(&wqe->lock);
+		raw_spin_unlock(&acct->lock);
 		unstalled = io_wait_on_hash(wqe, stall_hash);
-		raw_spin_lock(&wqe->lock);
+		raw_spin_lock(&acct->lock);
 		if (unstalled) {
 			clear_bit(IO_ACCT_STALLED_BIT, &acct->flags);
 			if (wq_has_sleeper(&wqe->wq->hash->wait))
@@ -538,7 +544,7 @@ static void io_assign_current_work(struct io_worker *worker,
 static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work);
 
 static void io_worker_handle_work(struct io_worker *worker)
-	__releases(wqe->lock)
+	__releases(acct->lock)
 {
 	struct io_wqe_acct *acct = io_wqe_get_acct(worker);
 	struct io_wqe *wqe = worker->wqe;
@@ -556,6 +562,7 @@ static void io_worker_handle_work(struct io_worker *worker)
 		 * clear the stalled flag.
 		 */
 		work = io_get_next_work(acct, worker);
+		raw_spin_unlock(&acct->lock);
 		if (work) {
 			__io_worker_busy(wqe, worker);
 
@@ -569,10 +576,9 @@ static void io_worker_handle_work(struct io_worker *worker)
 			raw_spin_lock(&worker->lock);
 			worker->next_work = work;
 			raw_spin_unlock(&worker->lock);
-		}
-		raw_spin_unlock(&wqe->lock);
-		if (!work)
+		} else {
 			break;
+		}
 		io_assign_current_work(worker, work);
 		__set_current_state(TASK_RUNNING);
 
@@ -609,7 +615,7 @@ static void io_worker_handle_work(struct io_worker *worker)
 			}
 		} while (work);
 
-		raw_spin_lock(&wqe->lock);
+		raw_spin_lock(&acct->lock);
 	} while (1);
 }
 
@@ -634,11 +640,14 @@ static int io_wqe_worker(void *data)
 
 		set_current_state(TASK_INTERRUPTIBLE);
 loop:
-		raw_spin_lock(&wqe->lock);
+		raw_spin_lock(&acct->lock);
 		if (io_acct_run_queue(acct)) {
 			io_worker_handle_work(worker);
 			goto loop;
+		} else {
+			raw_spin_unlock(&acct->lock);
 		}
+		raw_spin_lock(&wqe->lock);
 		/* timed out, exit unless we're the last worker */
 		if (last_timeout && acct->nr_workers > 1) {
 			acct->nr_workers--;
@@ -663,7 +672,7 @@ loop:
 	}
 
 	if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
-		raw_spin_lock(&wqe->lock);
+		raw_spin_lock(&acct->lock);
 		io_worker_handle_work(worker);
 	}
 
@@ -705,10 +714,7 @@ void io_wq_worker_sleeping(struct task_struct *tsk)
 		return;
 
 	worker->flags &= ~IO_WORKER_F_RUNNING;
-
-	raw_spin_lock(&worker->wqe->lock);
 	io_wqe_dec_running(worker);
-	raw_spin_unlock(&worker->wqe->lock);
 }
 
 static void io_init_new_worker(struct io_wqe *wqe, struct io_worker *worker,
@@ -778,10 +784,12 @@ static void create_worker_cont(struct callback_head *cb)
 				.cancel_all	= true,
 			};
 
+			raw_spin_unlock(&wqe->lock);
 			while (io_acct_cancel_pending_work(wqe, acct, &match))
-				raw_spin_lock(&wqe->lock);
+				;
+		} else {
+			raw_spin_unlock(&wqe->lock);
 		}
-		raw_spin_unlock(&wqe->lock);
 		io_worker_ref_put(wqe->wq);
 		kfree(worker);
 		return;
@@ -914,6 +922,7 @@ static bool io_wq_work_match_item(struct io_wq_work *work, void *data)
 static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work)
 {
 	struct io_wqe_acct *acct = io_work_get_acct(wqe, work);
+	struct io_cb_cancel_data match;
 	unsigned work_flags = work->flags;
 	bool do_create;
 
@@ -927,10 +936,12 @@ static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work)
 		return;
 	}
 
-	raw_spin_lock(&wqe->lock);
+	raw_spin_lock(&acct->lock);
 	io_wqe_insert_work(wqe, work);
 	clear_bit(IO_ACCT_STALLED_BIT, &acct->flags);
+	raw_spin_unlock(&acct->lock);
 
+	raw_spin_lock(&wqe->lock);
 	rcu_read_lock();
 	do_create = !io_wqe_activate_free_worker(wqe, acct);
 	rcu_read_unlock();
@@ -946,18 +957,18 @@ static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work)
 			return;
 
 		raw_spin_lock(&wqe->lock);
-		/* fatal condition, failed to create the first worker */
-		if (!acct->nr_workers) {
-			struct io_cb_cancel_data match = {
-				.fn		= io_wq_work_match_item,
-				.data		= work,
-				.cancel_all	= false,
-			};
-
-			if (io_acct_cancel_pending_work(wqe, acct, &match))
-				raw_spin_lock(&wqe->lock);
+		if (acct->nr_workers) {
+			raw_spin_unlock(&wqe->lock);
+			return;
 		}
 		raw_spin_unlock(&wqe->lock);
+
+		/* fatal condition, failed to create the first worker */
+		match.fn		= io_wq_work_match_item,
+		match.data		= work,
+		match.cancel_all	= false,
+
+		io_acct_cancel_pending_work(wqe, acct, &match);
 	}
 }
 
@@ -1032,22 +1043,23 @@ static inline void io_wqe_remove_pending(struct io_wqe *wqe,
 static bool io_acct_cancel_pending_work(struct io_wqe *wqe,
 					struct io_wqe_acct *acct,
 					struct io_cb_cancel_data *match)
-	__releases(wqe->lock)
 {
 	struct io_wq_work_node *node, *prev;
 	struct io_wq_work *work;
 
+	raw_spin_lock(&acct->lock);
 	wq_list_for_each(node, prev, &acct->work_list) {
 		work = container_of(node, struct io_wq_work, list);
 		if (!match->fn(work, match->data))
 			continue;
 		io_wqe_remove_pending(wqe, work, prev);
-		raw_spin_unlock(&wqe->lock);
+		raw_spin_unlock(&acct->lock);
 		io_run_cancel(work, wqe);
 		match->nr_pending++;
 		/* not safe to continue after unlock */
 		return true;
 	}
+	raw_spin_unlock(&acct->lock);
 
 	return false;
 }
@@ -1061,7 +1073,6 @@ retry:
 		struct io_wqe_acct *acct = io_get_acct(wqe, i == 0);
 
 		if (io_acct_cancel_pending_work(wqe, acct, match)) {
-			raw_spin_lock(&wqe->lock);
 			if (match->cancel_all)
 				goto retry;
 			break;
@@ -1103,13 +1114,11 @@ enum io_wq_cancel io_wq_cancel_cb(struct io_wq *wq, work_cancel_fn *cancel,
 	for_each_node(node) {
 		struct io_wqe *wqe = wq->wqes[node];
 
-		raw_spin_lock(&wqe->lock);
 		io_wqe_cancel_pending_work(wqe, &match);
-		if (match.nr_pending && !match.cancel_all) {
-			raw_spin_unlock(&wqe->lock);
+		if (match.nr_pending && !match.cancel_all)
 			return IO_WQ_CANCEL_OK;
-		}
 
+		raw_spin_lock(&wqe->lock);
 		io_wqe_cancel_running_work(wqe, &match);
 		raw_spin_unlock(&wqe->lock);
 		if (match.nr_running && !match.cancel_all)
@@ -1190,6 +1199,7 @@ struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
 			acct->index = i;
 			atomic_set(&acct->nr_running, 0);
 			INIT_WQ_LIST(&acct->work_list);
+			raw_spin_lock_init(&acct->lock);
 		}
 		wqe->wq = wq;
 		raw_spin_lock_init(&wqe->lock);
@@ -1282,9 +1292,7 @@ static void io_wq_destroy(struct io_wq *wq)
 			.fn		= io_wq_work_match_all,
 			.cancel_all	= true,
 		};
-		raw_spin_lock(&wqe->lock);
 		io_wqe_cancel_pending_work(wqe, &match);
-		raw_spin_unlock(&wqe->lock);
 		free_cpumask_var(wqe->cpu_mask);
 		kfree(wqe);
 	}