Merge tag 'for-5.15/io_uring-2021-08-30' of git://git.kernel.dk/linux-block

Pull io_uring updates from Jens Axboe:

 - cancellation cleanups (Hao, Pavel)

 - io-wq accounting cleanup (Hao)

 - io_uring submit locking fix (Hao)

 - io_uring link handling fixes (Hao)

 - fixed file improvements (wangyangbo, Pavel)

 - allow updates of linked timeouts like regular timeouts (Pavel)

 - IOPOLL fix (Pavel)

 - remove batched file get optimization (Pavel)

 - improve reference handling (Pavel)

 - IRQ task_work batching (Pavel)

 - allow pure fixed file, and add support for open/accept (Pavel)

 - GFP_ATOMIC RT kernel fix

 - multiple CQ ring waiter improvement

 - funnel IRQ completions through task_work

 - add support for limiting async workers explicitly

 - add different clocksource support for timeouts

 - io-wq wakeup race fix

 - lots of cleanups and improvement (Pavel et al)

* tag 'for-5.15/io_uring-2021-08-30' of git://git.kernel.dk/linux-block: (87 commits)
  io-wq: fix wakeup race when adding new work
  io-wq: wqe and worker locks no longer need to be IRQ safe
  io-wq: check max_worker limits if a worker transitions bound state
  io_uring: allow updating linked timeouts
  io_uring: keep ltimeouts in a list
  io_uring: support CLOCK_BOOTTIME/REALTIME for timeouts
  io-wq: provide a way to limit max number of workers
  io_uring: add build check for buf_index overflows
  io_uring: clarify io_req_task_cancel() locking
  io_uring: add task-refs-get helper
  io_uring: fix failed linkchain code logic
  io_uring: remove redundant req_set_fail()
  io_uring: don't free request to slab
  io_uring: accept directly into fixed file table
  io_uring: hand code io_accept() fd installing
  io_uring: openat directly into fixed fd table
  net: add accept helper not installing fd
  io_uring: fix io_try_cancel_userdata race for iowq
  io_uring: IRQ rw completion batching
  io_uring: batch task work locking
  ...

fs/io-wq.c

@@ -51,6 +51,10 @@ struct io_worker {
 
 	struct completion ref_done;
 
+	unsigned long create_state;
+	struct callback_head create_work;
+	int create_index;
+
 	struct rcu_head rcu;
 };
 
@@ -174,7 +178,7 @@ static void io_worker_exit(struct io_worker *worker)
 		complete(&worker->ref_done);
 	wait_for_completion(&worker->ref_done);
 
-	raw_spin_lock_irq(&wqe->lock);
+	raw_spin_lock(&wqe->lock);
 	if (worker->flags & IO_WORKER_F_FREE)
 		hlist_nulls_del_rcu(&worker->nulls_node);
 	list_del_rcu(&worker->all_list);
@@ -184,7 +188,7 @@ static void io_worker_exit(struct io_worker *worker)
 	worker->flags = 0;
 	current->flags &= ~PF_IO_WORKER;
 	preempt_enable();
-	raw_spin_unlock_irq(&wqe->lock);
+	raw_spin_unlock(&wqe->lock);
 
 	kfree_rcu(worker, rcu);
 	io_worker_ref_put(wqe->wq);
@@ -250,19 +254,20 @@ static void io_wqe_wake_worker(struct io_wqe *wqe, struct io_wqe_acct *acct)
 	if (!ret) {
 		bool do_create = false, first = false;
 
-		raw_spin_lock_irq(&wqe->lock);
+		raw_spin_lock(&wqe->lock);
 		if (acct->nr_workers < acct->max_workers) {
-			atomic_inc(&acct->nr_running);
-			atomic_inc(&wqe->wq->worker_refs);
 			if (!acct->nr_workers)
 				first = true;
 			acct->nr_workers++;
 			do_create = true;
 		}
-		raw_spin_unlock_irq(&wqe->lock);
-		if (do_create)
+		raw_spin_unlock(&wqe->lock);
+		if (do_create) {
+			atomic_inc(&acct->nr_running);
+			atomic_inc(&wqe->wq->worker_refs);
 			create_io_worker(wqe->wq, wqe, acct->index, first);
 		}
+	}
 }
 
 static void io_wqe_inc_running(struct io_worker *worker)
@@ -272,60 +277,63 @@ static void io_wqe_inc_running(struct io_worker *worker)
 	atomic_inc(&acct->nr_running);
 }
 
-struct create_worker_data {
-	struct callback_head work;
-	struct io_wqe *wqe;
-	int index;
-};
-
 static void create_worker_cb(struct callback_head *cb)
 {
-	struct create_worker_data *cwd;
+	struct io_worker *worker;
 	struct io_wq *wq;
 	struct io_wqe *wqe;
 	struct io_wqe_acct *acct;
 	bool do_create = false, first = false;
 
-	cwd = container_of(cb, struct create_worker_data, work);
-	wqe = cwd->wqe;
+	worker = container_of(cb, struct io_worker, create_work);
+	wqe = worker->wqe;
 	wq = wqe->wq;
-	acct = &wqe->acct[cwd->index];
-	raw_spin_lock_irq(&wqe->lock);
+	acct = &wqe->acct[worker->create_index];
+	raw_spin_lock(&wqe->lock);
 	if (acct->nr_workers < acct->max_workers) {
 		if (!acct->nr_workers)
 			first = true;
 		acct->nr_workers++;
 		do_create = true;
 	}
-	raw_spin_unlock_irq(&wqe->lock);
+	raw_spin_unlock(&wqe->lock);
 	if (do_create) {
-		create_io_worker(wq, wqe, cwd->index, first);
+		create_io_worker(wq, wqe, worker->create_index, first);
 	} else {
 		atomic_dec(&acct->nr_running);
 		io_worker_ref_put(wq);
 	}
-	kfree(cwd);
+	clear_bit_unlock(0, &worker->create_state);
+	io_worker_release(worker);
 }
 
-static void io_queue_worker_create(struct io_wqe *wqe, struct io_wqe_acct *acct)
+static void io_queue_worker_create(struct io_wqe *wqe, struct io_worker *worker,
+				   struct io_wqe_acct *acct)
 {
-	struct create_worker_data *cwd;
 	struct io_wq *wq = wqe->wq;
 
 	/* raced with exit, just ignore create call */
 	if (test_bit(IO_WQ_BIT_EXIT, &wq->state))
 		goto fail;
+	if (!io_worker_get(worker))
+		goto fail;
+	/*
+	 * create_state manages ownership of create_work/index. We should
+	 * only need one entry per worker, as the worker going to sleep
+	 * will trigger the condition, and waking will clear it once it
+	 * runs the task_work.
+	 */
+	if (test_bit(0, &worker->create_state) ||
+	    test_and_set_bit_lock(0, &worker->create_state))
+		goto fail_release;
 
-	cwd = kmalloc(sizeof(*cwd), GFP_ATOMIC);
-	if (cwd) {
-		init_task_work(&cwd->work, create_worker_cb);
-		cwd->wqe = wqe;
-		cwd->index = acct->index;
-		if (!task_work_add(wq->task, &cwd->work, TWA_SIGNAL))
+	init_task_work(&worker->create_work, create_worker_cb);
+	worker->create_index = acct->index;
+	if (!task_work_add(wq->task, &worker->create_work, TWA_SIGNAL))
 		return;
-
-		kfree(cwd);
-	}
+	clear_bit_unlock(0, &worker->create_state);
+fail_release:
+	io_worker_release(worker);
 fail:
 	atomic_dec(&acct->nr_running);
 	io_worker_ref_put(wq);
@@ -343,7 +351,7 @@ static void io_wqe_dec_running(struct io_worker *worker)
 	if (atomic_dec_and_test(&acct->nr_running) && io_wqe_run_queue(wqe)) {
 		atomic_inc(&acct->nr_running);
 		atomic_inc(&wqe->wq->worker_refs);
-		io_queue_worker_create(wqe, acct);
+		io_queue_worker_create(wqe, worker, acct);
 	}
 }
 
@@ -416,7 +424,28 @@ static void io_wait_on_hash(struct io_wqe *wqe, unsigned int hash)
 	spin_unlock(&wq->hash->wait.lock);
 }
 
-static struct io_wq_work *io_get_next_work(struct io_wqe *wqe)
+/*
+ * We can always run the work if the worker is currently the same type as
+ * the work (eg both are bound, or both are unbound). If they are not the
+ * same, only allow it if incrementing the worker count would be allowed.
+ */
+static bool io_worker_can_run_work(struct io_worker *worker,
+				   struct io_wq_work *work)
+{
+	struct io_wqe_acct *acct;
+
+	if (!(worker->flags & IO_WORKER_F_BOUND) !=
+	    !(work->flags & IO_WQ_WORK_UNBOUND))
+		return true;
+
+	/* not the same type, check if we'd go over the limit */
+	acct = io_work_get_acct(worker->wqe, work);
+	return acct->nr_workers < acct->max_workers;
+}
+
+static struct io_wq_work *io_get_next_work(struct io_wqe *wqe,
+					   struct io_worker *worker,
+					   bool *stalled)
 	__must_hold(wqe->lock)
 {
 	struct io_wq_work_node *node, *prev;
@@ -428,6 +457,9 @@ static struct io_wq_work *io_get_next_work(struct io_wqe *wqe)
 
 		work = container_of(node, struct io_wq_work, list);
 
+		if (!io_worker_can_run_work(worker, work))
+			break;
+
 		/* not hashed, can run anytime */
 		if (!io_wq_is_hashed(work)) {
 			wq_list_del(&wqe->work_list, node, prev);
@@ -454,6 +486,7 @@ static struct io_wq_work *io_get_next_work(struct io_wqe *wqe)
 		raw_spin_unlock(&wqe->lock);
 		io_wait_on_hash(wqe, stall_hash);
 		raw_spin_lock(&wqe->lock);
+		*stalled = true;
 	}
 
 	return NULL;
@@ -477,9 +510,9 @@ static void io_assign_current_work(struct io_worker *worker,
 		cond_resched();
 	}
 
-	spin_lock_irq(&worker->lock);
+	spin_lock(&worker->lock);
 	worker->cur_work = work;
-	spin_unlock_irq(&worker->lock);
+	spin_unlock(&worker->lock);
 }
 
 static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work);
@@ -493,6 +526,7 @@ static void io_worker_handle_work(struct io_worker *worker)
 
 	do {
 		struct io_wq_work *work;
+		bool stalled;
 get_next:
 		/*
 		 * If we got some work, mark us as busy. If we didn't, but
@@ -501,13 +535,14 @@ static void io_worker_handle_work(struct io_worker *worker)
 		 * can't make progress, any work completion or insertion will
 		 * clear the stalled flag.
 		 */
-		work = io_get_next_work(wqe);
+		stalled = false;
+		work = io_get_next_work(wqe, worker, &stalled);
 		if (work)
 			__io_worker_busy(wqe, worker, work);
-		else if (!wq_list_empty(&wqe->work_list))
+		else if (stalled)
 			wqe->flags |= IO_WQE_FLAG_STALLED;
 
-		raw_spin_unlock_irq(&wqe->lock);
+		raw_spin_unlock(&wqe->lock);
 		if (!work)
 			break;
 		io_assign_current_work(worker, work);
@@ -539,16 +574,16 @@ static void io_worker_handle_work(struct io_worker *worker)
 				clear_bit(hash, &wq->hash->map);
 				if (wq_has_sleeper(&wq->hash->wait))
 					wake_up(&wq->hash->wait);
-				raw_spin_lock_irq(&wqe->lock);
+				raw_spin_lock(&wqe->lock);
 				wqe->flags &= ~IO_WQE_FLAG_STALLED;
 				/* skip unnecessary unlock-lock wqe->lock */
 				if (!work)
 					goto get_next;
-				raw_spin_unlock_irq(&wqe->lock);
+				raw_spin_unlock(&wqe->lock);
 			}
 		} while (work);
 
-		raw_spin_lock_irq(&wqe->lock);
+		raw_spin_lock(&wqe->lock);
 	} while (1);
 }
 
@@ -569,13 +604,13 @@ static int io_wqe_worker(void *data)
 
 		set_current_state(TASK_INTERRUPTIBLE);
 loop:
-		raw_spin_lock_irq(&wqe->lock);
+		raw_spin_lock(&wqe->lock);
 		if (io_wqe_run_queue(wqe)) {
 			io_worker_handle_work(worker);
 			goto loop;
 		}
 		__io_worker_idle(wqe, worker);
-		raw_spin_unlock_irq(&wqe->lock);
+		raw_spin_unlock(&wqe->lock);
 		if (io_flush_signals())
 			continue;
 		ret = schedule_timeout(WORKER_IDLE_TIMEOUT);
@@ -594,7 +629,7 @@ static int io_wqe_worker(void *data)
 	}
 
 	if (test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
-		raw_spin_lock_irq(&wqe->lock);
+		raw_spin_lock(&wqe->lock);
 		io_worker_handle_work(worker);
 	}
 
@@ -636,9 +671,9 @@ void io_wq_worker_sleeping(struct task_struct *tsk)
 
 	worker->flags &= ~IO_WORKER_F_RUNNING;
 
-	raw_spin_lock_irq(&worker->wqe->lock);
+	raw_spin_lock(&worker->wqe->lock);
 	io_wqe_dec_running(worker);
-	raw_spin_unlock_irq(&worker->wqe->lock);
+	raw_spin_unlock(&worker->wqe->lock);
 }
 
 static void create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index, bool first)
@@ -664,9 +699,9 @@ static void create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index, bo
 		kfree(worker);
 fail:
 		atomic_dec(&acct->nr_running);
-		raw_spin_lock_irq(&wqe->lock);
+		raw_spin_lock(&wqe->lock);
 		acct->nr_workers--;
-		raw_spin_unlock_irq(&wqe->lock);
+		raw_spin_unlock(&wqe->lock);
 		io_worker_ref_put(wq);
 		return;
 	}
@@ -676,7 +711,7 @@ static void create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index, bo
 	set_cpus_allowed_ptr(tsk, wqe->cpu_mask);
 	tsk->flags |= PF_NO_SETAFFINITY;
 
-	raw_spin_lock_irq(&wqe->lock);
+	raw_spin_lock(&wqe->lock);
 	hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);
 	list_add_tail_rcu(&worker->all_list, &wqe->all_list);
 	worker->flags |= IO_WORKER_F_FREE;
@@ -684,7 +719,7 @@ static void create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index, bo
 		worker->flags |= IO_WORKER_F_BOUND;
 	if (first && (worker->flags & IO_WORKER_F_BOUND))
 		worker->flags |= IO_WORKER_F_FIXED;
-	raw_spin_unlock_irq(&wqe->lock);
+	raw_spin_unlock(&wqe->lock);
 	wake_up_new_task(tsk);
 }
 
@@ -759,8 +794,7 @@ static void io_wqe_insert_work(struct io_wqe *wqe, struct io_wq_work *work)
 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);
-	int work_flags;
-	unsigned long flags;
+	bool do_wake;
 
 	/*
 	 * If io-wq is exiting for this task, or if the request has explicitly
@@ -772,14 +806,14 @@ static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work)
 		return;
 	}
 
-	work_flags = work->flags;
-	raw_spin_lock_irqsave(&wqe->lock, flags);
+	raw_spin_lock(&wqe->lock);
 	io_wqe_insert_work(wqe, work);
 	wqe->flags &= ~IO_WQE_FLAG_STALLED;
-	raw_spin_unlock_irqrestore(&wqe->lock, flags);
+	do_wake = (work->flags & IO_WQ_WORK_CONCURRENT) ||
+			!atomic_read(&acct->nr_running);
+	raw_spin_unlock(&wqe->lock);
 
-	if ((work_flags & IO_WQ_WORK_CONCURRENT) ||
-	    !atomic_read(&acct->nr_running))
+	if (do_wake)
 		io_wqe_wake_worker(wqe, acct);
 }
 
@@ -805,19 +839,18 @@ void io_wq_hash_work(struct io_wq_work *work, void *val)
 static bool io_wq_worker_cancel(struct io_worker *worker, void *data)
 {
 	struct io_cb_cancel_data *match = data;
-	unsigned long flags;
 
 	/*
 	 * Hold the lock to avoid ->cur_work going out of scope, caller
 	 * may dereference the passed in work.
 	 */
-	spin_lock_irqsave(&worker->lock, flags);
+	spin_lock(&worker->lock);
 	if (worker->cur_work &&
 	    match->fn(worker->cur_work, match->data)) {
 		set_notify_signal(worker->task);
 		match->nr_running++;
 	}
-	spin_unlock_irqrestore(&worker->lock, flags);
+	spin_unlock(&worker->lock);
 
 	return match->nr_running && !match->cancel_all;
 }
@@ -845,16 +878,15 @@ static void io_wqe_cancel_pending_work(struct io_wqe *wqe,
 {
 	struct io_wq_work_node *node, *prev;
 	struct io_wq_work *work;
-	unsigned long flags;
 
 retry:
-	raw_spin_lock_irqsave(&wqe->lock, flags);
+	raw_spin_lock(&wqe->lock);
 	wq_list_for_each(node, prev, &wqe->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_irqrestore(&wqe->lock, flags);
+		raw_spin_unlock(&wqe->lock);
 		io_run_cancel(work, wqe);
 		match->nr_pending++;
 		if (!match->cancel_all)
@@ -863,7 +895,7 @@ static void io_wqe_cancel_pending_work(struct io_wqe *wqe,
 		/* not safe to continue after unlock */
 		goto retry;
 	}
-	raw_spin_unlock_irqrestore(&wqe->lock, flags);
+	raw_spin_unlock(&wqe->lock);
 }
 
 static void io_wqe_cancel_running_work(struct io_wqe *wqe,
@@ -1004,12 +1036,12 @@ struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
 
 static bool io_task_work_match(struct callback_head *cb, void *data)
 {
-	struct create_worker_data *cwd;
+	struct io_worker *worker;
 
 	if (cb->func != create_worker_cb)
 		return false;
-	cwd = container_of(cb, struct create_worker_data, work);
-	return cwd->wqe->wq == data;
+	worker = container_of(cb, struct io_worker, create_work);
+	return worker->wqe->wq == data;
 }
 
 void io_wq_exit_start(struct io_wq *wq)
@@ -1026,12 +1058,13 @@ static void io_wq_exit_workers(struct io_wq *wq)
 		return;
 
 	while ((cb = task_work_cancel_match(wq->task, io_task_work_match, wq)) != NULL) {
-		struct create_worker_data *cwd;
+		struct io_worker *worker;
 
-		cwd = container_of(cb, struct create_worker_data, work);
-		atomic_dec(&cwd->wqe->acct[cwd->index].nr_running);
+		worker = container_of(cb, struct io_worker, create_work);
+		atomic_dec(&worker->wqe->acct[worker->create_index].nr_running);
 		io_worker_ref_put(wq);
-		kfree(cwd);
+		clear_bit_unlock(0, &worker->create_state);
+		io_worker_release(worker);
 	}
 
 	rcu_read_lock();
@@ -1143,6 +1176,35 @@ int io_wq_cpu_affinity(struct io_wq *wq, cpumask_var_t mask)
 	return 0;
 }
 
+/*
+ * Set max number of unbounded workers, returns old value. If new_count is 0,
+ * then just return the old value.
+ */
+int io_wq_max_workers(struct io_wq *wq, int *new_count)
+{
+	int i, node, prev = 0;
+
+	for (i = 0; i < 2; i++) {
+		if (new_count[i] > task_rlimit(current, RLIMIT_NPROC))
+			new_count[i] = task_rlimit(current, RLIMIT_NPROC);
+	}
+
+	rcu_read_lock();
+	for_each_node(node) {
+		struct io_wqe_acct *acct;
+
+		for (i = 0; i < 2; i++) {
+			acct = &wq->wqes[node]->acct[i];
+			prev = max_t(int, acct->max_workers, prev);
+			if (new_count[i])
+				acct->max_workers = new_count[i];
+			new_count[i] = prev;
+		}
+	}
+	rcu_read_unlock();
+	return 0;
+}
+
 static __init int io_wq_init(void)
 {
 	int ret;

fs/io-wq.h

@@ -44,6 +44,7 @@ static inline void wq_list_add_after(struct io_wq_work_node *node,
 static inline void wq_list_add_tail(struct io_wq_work_node *node,
 				    struct io_wq_work_list *list)
 {
+	node->next = NULL;
 	if (!list->first) {
 		list->last = node;
 		WRITE_ONCE(list->first, node);
@@ -51,7 +52,6 @@ static inline void wq_list_add_tail(struct io_wq_work_node *node,
 		list->last->next = node;
 		list->last = node;
 	}
-	node->next = NULL;
 }
 
 static inline void wq_list_cut(struct io_wq_work_list *list,
@@ -128,6 +128,7 @@ void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work);
 void io_wq_hash_work(struct io_wq_work *work, void *val);
 
 int io_wq_cpu_affinity(struct io_wq *wq, cpumask_var_t mask);
+int io_wq_max_workers(struct io_wq *wq, int *new_count);
 
 static inline bool io_wq_is_hashed(struct io_wq_work *work)
 {

include/linux/io_uring.h

@@ -7,17 +7,18 @@
 
 #if defined(CONFIG_IO_URING)
 struct sock *io_uring_get_socket(struct file *file);
-void __io_uring_cancel(struct files_struct *files);
+void __io_uring_cancel(bool cancel_all);
 void __io_uring_free(struct task_struct *tsk);
 
-static inline void io_uring_files_cancel(struct files_struct *files)
+static inline void io_uring_files_cancel(void)
 {
 	if (current->io_uring)
-		__io_uring_cancel(files);
+		__io_uring_cancel(false);
 }
 static inline void io_uring_task_cancel(void)
 {
-	return io_uring_files_cancel(NULL);
+	if (current->io_uring)
+		__io_uring_cancel(true);
 }
 static inline void io_uring_free(struct task_struct *tsk)
 {
@@ -32,7 +33,7 @@ static inline struct sock *io_uring_get_socket(struct file *file)
 static inline void io_uring_task_cancel(void)
 {
 }
-static inline void io_uring_files_cancel(struct files_struct *files)
+static inline void io_uring_files_cancel(void)
 {
 }
 static inline void io_uring_free(struct task_struct *tsk)

include/linux/socket.h

@@ -421,6 +421,9 @@ extern int __sys_accept4_file(struct file *file, unsigned file_flags,
 			struct sockaddr __user *upeer_sockaddr,
 			 int __user *upeer_addrlen, int flags,
 			 unsigned long nofile);
+extern struct file *do_accept(struct file *file, unsigned file_flags,
+			      struct sockaddr __user *upeer_sockaddr,
+			      int __user *upeer_addrlen, int flags);
 extern int __sys_accept4(int fd, struct sockaddr __user *upeer_sockaddr,
 			 int __user *upeer_addrlen, int flags);
 extern int __sys_socket(int family, int type, int protocol);

include/uapi/linux/io_uring.h

@@ -55,7 +55,10 @@ struct io_uring_sqe {
 	} __attribute__((packed));
 	/* personality to use, if used */
 	__u16	personality;
+	union {
 		__s32	splice_fd_in;
+		__u32	file_index;
+	};
 	__u64	__pad2[2];
 };
 
@@ -148,7 +151,11 @@ enum {
  */
 #define IORING_TIMEOUT_ABS		(1U << 0)
 #define IORING_TIMEOUT_UPDATE		(1U << 1)
-
+#define IORING_TIMEOUT_BOOTTIME		(1U << 2)
+#define IORING_TIMEOUT_REALTIME		(1U << 3)
+#define IORING_LINK_TIMEOUT_UPDATE	(1U << 4)
+#define IORING_TIMEOUT_CLOCK_MASK	(IORING_TIMEOUT_BOOTTIME | IORING_TIMEOUT_REALTIME)
+#define IORING_TIMEOUT_UPDATE_MASK	(IORING_TIMEOUT_UPDATE | IORING_LINK_TIMEOUT_UPDATE)
 /*
  * sqe->splice_flags
  * extends splice(2) flags
@@ -306,6 +313,9 @@ enum {
 	IORING_REGISTER_IOWQ_AFF		= 17,
 	IORING_UNREGISTER_IOWQ_AFF		= 18,
 
+	/* set/get max number of workers */
+	IORING_REGISTER_IOWQ_MAX_WORKERS	= 19,
+
 	/* this goes last */
 	IORING_REGISTER_LAST
 };

kernel/exit.c

@@ -777,7 +777,7 @@ void __noreturn do_exit(long code)
 		schedule();
 	}
 
-	io_uring_files_cancel(tsk->files);
+	io_uring_files_cancel();
 	exit_signals(tsk);  /* sets PF_EXITING */
 
 	/* sync mm's RSS info before statistics gathering */

net/socket.c

@@ -1722,32 +1722,22 @@ SYSCALL_DEFINE2(listen, int, fd, int, backlog)
 	return __sys_listen(fd, backlog);
 }
 
-int __sys_accept4_file(struct file *file, unsigned file_flags,
+struct file *do_accept(struct file *file, unsigned file_flags,
 		       struct sockaddr __user *upeer_sockaddr,
-		       int __user *upeer_addrlen, int flags,
-		       unsigned long nofile)
+		       int __user *upeer_addrlen, int flags)
 {
 	struct socket *sock, *newsock;
 	struct file *newfile;
-	int err, len, newfd;
+	int err, len;
 	struct sockaddr_storage address;
 
-	if (flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
-		return -EINVAL;
-
-	if (SOCK_NONBLOCK != O_NONBLOCK && (flags & SOCK_NONBLOCK))
-		flags = (flags & ~SOCK_NONBLOCK) | O_NONBLOCK;
-
 	sock = sock_from_file(file);
-	if (!sock) {
-		err = -ENOTSOCK;
-		goto out;
-	}
+	if (!sock)
+		return ERR_PTR(-ENOTSOCK);
 
-	err = -ENFILE;
 	newsock = sock_alloc();
 	if (!newsock)
-		goto out;
+		return ERR_PTR(-ENFILE);
 
 	newsock->type = sock->type;
 	newsock->ops = sock->ops;
@@ -1758,18 +1748,9 @@ int __sys_accept4_file(struct file *file, unsigned file_flags,
 	 */
 	__module_get(newsock->ops->owner);
 
-	newfd = __get_unused_fd_flags(flags, nofile);
-	if (unlikely(newfd < 0)) {
-		err = newfd;
-		sock_release(newsock);
-		goto out;
-	}
 	newfile = sock_alloc_file(newsock, flags, sock->sk->sk_prot_creator->name);
-	if (IS_ERR(newfile)) {
-		err = PTR_ERR(newfile);
-		put_unused_fd(newfd);
-		goto out;
-	}
+	if (IS_ERR(newfile))
+		return newfile;
 
 	err = security_socket_accept(sock, newsock);
 	if (err)
@@ -1794,16 +1775,38 @@ int __sys_accept4_file(struct file *file, unsigned file_flags,
 	}
 
 	/* File flags are not inherited via accept() unlike another OSes. */
-
-	fd_install(newfd, newfile);
-	err = newfd;
-out:
-	return err;
+	return newfile;
 out_fd:
 	fput(newfile);
-	put_unused_fd(newfd);
-	goto out;
+	return ERR_PTR(err);
+}
 
+int __sys_accept4_file(struct file *file, unsigned file_flags,
+		       struct sockaddr __user *upeer_sockaddr,
+		       int __user *upeer_addrlen, int flags,
+		       unsigned long nofile)
+{
+	struct file *newfile;
+	int newfd;
+
+	if (flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK))
+		return -EINVAL;
+
+	if (SOCK_NONBLOCK != O_NONBLOCK && (flags & SOCK_NONBLOCK))
+		flags = (flags & ~SOCK_NONBLOCK) | O_NONBLOCK;
+
+	newfd = __get_unused_fd_flags(flags, nofile);
+	if (unlikely(newfd < 0))
+		return newfd;
+
+	newfile = do_accept(file, file_flags, upeer_sockaddr, upeer_addrlen,
+			    flags);
+	if (IS_ERR(newfile)) {
+		put_unused_fd(newfd);
+		return PTR_ERR(newfile);
+	}
+	fd_install(newfd, newfile);
+	return newfd;
 }
 
 /*