Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio updates from Michael Tsirkin:
 "Several new features here:

   - virtio-net is finally supported in vduse

   - virtio (balloon and mem) interaction with suspend is improved

   - vhost-scsi now handles signals better/faster

  And fixes, cleanups all over the place"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (48 commits)
  virtio-pci: Check if is_avq is NULL
  virtio: delete vq in vp_find_vqs_msix() when request_irq() fails
  MAINTAINERS: add Eugenio Pérez as reviewer
  vhost-vdpa: Remove usage of the deprecated ida_simple_xx() API
  vp_vdpa: don't allocate unused msix vectors
  sound: virtio: drop owner assignment
  fuse: virtio: drop owner assignment
  scsi: virtio: drop owner assignment
  rpmsg: virtio: drop owner assignment
  nvdimm: virtio_pmem: drop owner assignment
  wifi: mac80211_hwsim: drop owner assignment
  vsock/virtio: drop owner assignment
  net: 9p: virtio: drop owner assignment
  net: virtio: drop owner assignment
  net: caif: virtio: drop owner assignment
  misc: nsm: drop owner assignment
  iommu: virtio: drop owner assignment
  drm/virtio: drop owner assignment
  gpio: virtio: drop owner assignment
  firmware: arm_scmi: virtio: drop owner assignment
  ...

3 files changed, 36 insertions, 26 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index cd3aa9042f1a..f95a2c1338a8 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -413,10 +413,7 @@ static void coredump_task_exit(struct task_struct *tsk)
 	tsk->flags |= PF_POSTCOREDUMP;
 	core_state = tsk->signal->core_state;
 	spin_unlock_irq(&tsk->sighand->siglock);
-
-	/* The vhost_worker does not particpate in coredumps */
-	if (core_state &&
-	    ((tsk->flags & (PF_IO_WORKER | PF_USER_WORKER)) != PF_USER_WORKER)) {
+	if (core_state) {
 		struct core_thread self;
 
 		self.task = current;
diff --git a/kernel/signal.c b/kernel/signal.c
index 01c4c46a51a8..1f9dd41c04be 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1375,9 +1375,7 @@ int zap_other_threads(struct task_struct *p)
 
 	for_other_threads(p, t) {
 		task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
-		/* Don't require de_thread to wait for the vhost_worker */
-		if ((t->flags & (PF_IO_WORKER | PF_USER_WORKER)) != PF_USER_WORKER)
-			count++;
+		count++;
 
 		/* Don't bother with already dead threads */
 		if (t->exit_state)
diff --git a/kernel/vhost_task.c b/kernel/vhost_task.c
index da35e5b7f047..8800f5acc007 100644
--- a/kernel/vhost_task.c
+++ b/kernel/vhost_task.c
@@ -10,38 +10,32 @@
 
 enum vhost_task_flags {
 	VHOST_TASK_FLAGS_STOP,
+	VHOST_TASK_FLAGS_KILLED,
 };
 
 struct vhost_task {
 	bool (*fn)(void *data);
+	void (*handle_sigkill)(void *data);
 	void *data;
 	struct completion exited;
 	unsigned long flags;
 	struct task_struct *task;
+	/* serialize SIGKILL and vhost_task_stop calls */
+	struct mutex exit_mutex;
 };
 
 static int vhost_task_fn(void *data)
 {
 	struct vhost_task *vtsk = data;
-	bool dead = false;
 
 	for (;;) {
 		bool did_work;
 
-		if (!dead && signal_pending(current)) {
+		if (signal_pending(current)) {
 			struct ksignal ksig;
-			/*
-			 * Calling get_signal will block in SIGSTOP,
-			 * or clear fatal_signal_pending, but remember
-			 * what was set.
-			 *
-			 * This thread won't actually exit until all
-			 * of the file descriptors are closed, and
-			 * the release function is called.
-			 */
-			dead = get_signal(&ksig);
-			if (dead)
-				clear_thread_flag(TIF_SIGPENDING);
+
+			if (get_signal(&ksig))
+				break;
 		}
 
 		/* mb paired w/ vhost_task_stop */
@@ -57,7 +51,19 @@ static int vhost_task_fn(void *data)
 			schedule();
 	}
 
+	mutex_lock(&vtsk->exit_mutex);
+	/*
+	 * If a vhost_task_stop and SIGKILL race, we can ignore the SIGKILL.
+	 * When the vhost layer has called vhost_task_stop it's already stopped
+	 * new work and flushed.
+	 */
+	if (!test_bit(VHOST_TASK_FLAGS_STOP, &vtsk->flags)) {
+		set_bit(VHOST_TASK_FLAGS_KILLED, &vtsk->flags);
+		vtsk->handle_sigkill(vtsk->data);
+	}
+	mutex_unlock(&vtsk->exit_mutex);
 	complete(&vtsk->exited);
+
 	do_exit(0);
 }
 
@@ -78,12 +84,17 @@ EXPORT_SYMBOL_GPL(vhost_task_wake);
  * @vtsk: vhost_task to stop
  *
  * vhost_task_fn ensures the worker thread exits after
- * VHOST_TASK_FLAGS_SOP becomes true.
+ * VHOST_TASK_FLAGS_STOP becomes true.
  */
 void vhost_task_stop(struct vhost_task *vtsk)
 {
-	set_bit(VHOST_TASK_FLAGS_STOP, &vtsk->flags);
-	vhost_task_wake(vtsk);
+	mutex_lock(&vtsk->exit_mutex);
+	if (!test_bit(VHOST_TASK_FLAGS_KILLED, &vtsk->flags)) {
+		set_bit(VHOST_TASK_FLAGS_STOP, &vtsk->flags);
+		vhost_task_wake(vtsk);
+	}
+	mutex_unlock(&vtsk->exit_mutex);
+
 	/*
 	 * Make sure vhost_task_fn is no longer accessing the vhost_task before
 	 * freeing it below.
@@ -96,14 +107,16 @@ EXPORT_SYMBOL_GPL(vhost_task_stop);
 /**
  * vhost_task_create - create a copy of a task to be used by the kernel
  * @fn: vhost worker function
- * @arg: data to be passed to fn
+ * @handle_sigkill: vhost function to handle when we are killed
+ * @arg: data to be passed to fn and handled_kill
  * @name: the thread's name
  *
  * This returns a specialized task for use by the vhost layer or NULL on
  * failure. The returned task is inactive, and the caller must fire it up
  * through vhost_task_start().
  */
-struct vhost_task *vhost_task_create(bool (*fn)(void *), void *arg,
+struct vhost_task *vhost_task_create(bool (*fn)(void *),
+				     void (*handle_sigkill)(void *), void *arg,
 				     const char *name)
 {
 	struct kernel_clone_args args = {
@@ -122,8 +135,10 @@ struct vhost_task *vhost_task_create(bool (*fn)(void *), void *arg,
 	if (!vtsk)
 		return NULL;
 	init_completion(&vtsk->exited);
+	mutex_init(&vtsk->exit_mutex);
 	vtsk->data = arg;
 	vtsk->fn = fn;
+	vtsk->handle_sigkill = handle_sigkill;
 
 	args.fn_arg = vtsk;