path: root/bcm2835-vchiq-use-interruptible-waits.patch

From 0fa32f5500a1b4a81d6856ad389d654f1377f744 Mon Sep 17 00:00:00 2001
From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Date: Thu, 9 May 2019 16:31:33 +0200
Subject: [PATCH 1/4] staging: vchiq_2835_arm: revert "quit using custom
 down_interruptible()"

The killable version of down() is meant to be used on situations where
it should not fail at all costs, but still have the convenience of being
able to kill it if really necessary. VCHIQ doesn't fit this criteria, as
it's mainly used as an interface to V4L2 and ALSA devices.

Fixes: ff5979ad8636 ("staging: vchiq_2835_arm: quit using custom down_interruptible()")
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
---
 .../staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c  | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
index a9cc01e8e6c5..833b28e9ba4b 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
@@ -553,7 +553,7 @@ create_pagelist(char __user *buf, size_t count, unsigned short type)
 		(g_cache_line_size - 1)))) {
 		char *fragments;
 
-		if (down_killable(&g_free_fragments_sema)) {
+		if (down_interruptible(&g_free_fragments_sema) != 0) {
 			cleanup_pagelistinfo(pagelistinfo);
 			return NULL;
 		}
-- 
2.21.0

From 7c73f359a4f269b611ebc00a910933d2d1926ebe Mon Sep 17 00:00:00 2001
From: Peter Robinson <pbrobinson@gmail.com>
Date: Thu, 4 Jul 2019 17:31:38 +0100
Subject: [PATCH 2/4] staging: vchiq: revert "switch to
 wait_for_completion_killable"

The killable version of wait_for_completion() is meant to be used on
situations where it should not fail at all costs, but still have the
convenience of being able to kill it if really necessary. VCHIQ doesn't
fit this criteria, as it's mainly used as an interface to V4L2 and ALSA
devices.

Fixes: a772f116702e ("staging: vchiq: switch to wait_for_completion_killable")
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
---
 .../interface/vchiq_arm/vchiq_arm.c           | 21 ++++++++++---------
 .../interface/vchiq_arm/vchiq_core.c          | 21 ++++++++++---------
 .../interface/vchiq_arm/vchiq_util.c          |  6 +++---
 3 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
index 064d0db4c51e..ccfb8218b83c 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
@@ -560,7 +560,8 @@ add_completion(VCHIQ_INSTANCE_T instance, VCHIQ_REASON_T reason,
 		vchiq_log_trace(vchiq_arm_log_level,
 			"%s - completion queue full", __func__);
 		DEBUG_COUNT(COMPLETION_QUEUE_FULL_COUNT);
-		if (wait_for_completion_killable( &instance->remove_event)) {
+		if (wait_for_completion_interruptible(
+					&instance->remove_event)) {
 			vchiq_log_info(vchiq_arm_log_level,
 				"service_callback interrupted");
 			return VCHIQ_RETRY;
@@ -671,7 +672,7 @@ service_callback(VCHIQ_REASON_T reason, struct vchiq_header *header,
 			}
 
 			DEBUG_TRACE(SERVICE_CALLBACK_LINE);
-			if (wait_for_completion_killable(
+			if (wait_for_completion_interruptible(
 						&user_service->remove_event)
 				!= 0) {
 				vchiq_log_info(vchiq_arm_log_level,
@@ -1006,7 +1007,7 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		   has been closed until the client library calls the
 		   CLOSE_DELIVERED ioctl, signalling close_event. */
 		if (user_service->close_pending &&
-			wait_for_completion_killable(
+			wait_for_completion_interruptible(
 				&user_service->close_event))
 			status = VCHIQ_RETRY;
 		break;
@@ -1182,7 +1183,7 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 
 			DEBUG_TRACE(AWAIT_COMPLETION_LINE);
 			mutex_unlock(&instance->completion_mutex);
-			rc = wait_for_completion_killable(
+			rc = wait_for_completion_interruptible(
 						&instance->insert_event);
 			mutex_lock(&instance->completion_mutex);
 			if (rc != 0) {
@@ -1352,7 +1353,7 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 			do {
 				spin_unlock(&msg_queue_spinlock);
 				DEBUG_TRACE(DEQUEUE_MESSAGE_LINE);
-				if (wait_for_completion_killable(
+				if (wait_for_completion_interruptible(
 					&user_service->insert_event)) {
 					vchiq_log_info(vchiq_arm_log_level,
 						"DEQUEUE_MESSAGE interrupted");
@@ -2360,7 +2361,7 @@ vchiq_keepalive_thread_func(void *v)
 	while (1) {
 		long rc = 0, uc = 0;
 
-		if (wait_for_completion_killable(&arm_state->ka_evt)
+		if (wait_for_completion_interruptible(&arm_state->ka_evt)
 				!= 0) {
 			vchiq_log_error(vchiq_susp_log_level,
 				"%s interrupted", __func__);
@@ -2611,7 +2612,7 @@ block_resume(struct vchiq_arm_state *arm_state)
 		write_unlock_bh(&arm_state->susp_res_lock);
 		vchiq_log_info(vchiq_susp_log_level, "%s wait for previously "
 			"blocked clients", __func__);
-		if (wait_for_completion_killable_timeout(
+		if (wait_for_completion_interruptible_timeout(
 				&arm_state->blocked_blocker, timeout_val)
 					<= 0) {
 			vchiq_log_error(vchiq_susp_log_level, "%s wait for "
@@ -2637,7 +2638,7 @@ block_resume(struct vchiq_arm_state *arm_state)
 		write_unlock_bh(&arm_state->susp_res_lock);
 		vchiq_log_info(vchiq_susp_log_level, "%s wait for resume",
 			__func__);
-		if (wait_for_completion_killable_timeout(
+		if (wait_for_completion_interruptible_timeout(
 				&arm_state->vc_resume_complete, timeout_val)
 					<= 0) {
 			vchiq_log_error(vchiq_susp_log_level, "%s wait for "
@@ -2844,7 +2845,7 @@ vchiq_arm_force_suspend(struct vchiq_state *state)
 	do {
 		write_unlock_bh(&arm_state->susp_res_lock);
 
-		rc = wait_for_completion_killable_timeout(
+		rc = wait_for_completion_interruptible_timeout(
 				&arm_state->vc_suspend_complete,
 				msecs_to_jiffies(FORCE_SUSPEND_TIMEOUT_MS));
 
@@ -2940,7 +2941,7 @@ vchiq_arm_allow_resume(struct vchiq_state *state)
 	write_unlock_bh(&arm_state->susp_res_lock);
 
 	if (resume) {
-		if (wait_for_completion_killable(
+		if (wait_for_completion_interruptible(
 			&arm_state->vc_resume_complete) < 0) {
 			vchiq_log_error(vchiq_susp_log_level,
 				"%s interrupted", __func__);
diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
index 819813e742d8..bc5661dde987 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
@@ -590,7 +590,7 @@ reserve_space(struct vchiq_state *state, size_t space, int is_blocking)
 			remote_event_signal(&state->remote->trigger);
 
 			if (!is_blocking ||
-				(wait_for_completion_killable(
+				(wait_for_completion_interruptible(
 				&state->slot_available_event)))
 				return NULL; /* No space available */
 		}
@@ -860,7 +860,7 @@ queue_message(struct vchiq_state *state, struct vchiq_service *service,
 			spin_unlock(&quota_spinlock);
 			mutex_unlock(&state->slot_mutex);
 
-			if (wait_for_completion_killable(
+			if (wait_for_completion_interruptible(
 						&state->data_quota_event))
 				return VCHIQ_RETRY;
 
@@ -891,7 +891,7 @@ queue_message(struct vchiq_state *state, struct vchiq_service *service,
 				service_quota->slot_use_count);
 			VCHIQ_SERVICE_STATS_INC(service, quota_stalls);
 			mutex_unlock(&state->slot_mutex);
-			if (wait_for_completion_killable(
+			if (wait_for_completion_interruptible(
 						&service_quota->quota_event))
 				return VCHIQ_RETRY;
 			if (service->closing)
@@ -1740,7 +1740,8 @@ parse_rx_slots(struct vchiq_state *state)
 					&service->bulk_rx : &service->bulk_tx;
 
 				DEBUG_TRACE(PARSE_LINE);
-				if (mutex_lock_killable(&service->bulk_mutex)) {
+				if (mutex_lock_killable(
+					&service->bulk_mutex) != 0) {
 					DEBUG_TRACE(PARSE_LINE);
 					goto bail_not_ready;
 				}
@@ -2458,7 +2459,7 @@ vchiq_open_service_internal(struct vchiq_service *service, int client_id)
 			       QMFLAGS_IS_BLOCKING);
 	if (status == VCHIQ_SUCCESS) {
 		/* Wait for the ACK/NAK */
-		if (wait_for_completion_killable(&service->remove_event)) {
+		if (wait_for_completion_interruptible(&service->remove_event)) {
 			status = VCHIQ_RETRY;
 			vchiq_release_service_internal(service);
 		} else if ((service->srvstate != VCHIQ_SRVSTATE_OPEN) &&
@@ -2825,7 +2826,7 @@ vchiq_connect_internal(struct vchiq_state *state, VCHIQ_INSTANCE_T instance)
 	}
 
 	if (state->conn_state == VCHIQ_CONNSTATE_CONNECTING) {
-		if (wait_for_completion_killable(&state->connect))
+		if (wait_for_completion_interruptible(&state->connect))
 			return VCHIQ_RETRY;
 
 		vchiq_set_conn_state(state, VCHIQ_CONNSTATE_CONNECTED);
@@ -2924,7 +2925,7 @@ vchiq_close_service(VCHIQ_SERVICE_HANDLE_T handle)
 	}
 
 	while (1) {
-		if (wait_for_completion_killable(&service->remove_event)) {
+		if (wait_for_completion_interruptible(&service->remove_event)) {
 			status = VCHIQ_RETRY;
 			break;
 		}
@@ -2985,7 +2986,7 @@ vchiq_remove_service(VCHIQ_SERVICE_HANDLE_T handle)
 		request_poll(service->state, service, VCHIQ_POLL_REMOVE);
 	}
 	while (1) {
-		if (wait_for_completion_killable(&service->remove_event)) {
+		if (wait_for_completion_interruptible(&service->remove_event)) {
 			status = VCHIQ_RETRY;
 			break;
 		}
@@ -3068,7 +3069,7 @@ VCHIQ_STATUS_T vchiq_bulk_transfer(VCHIQ_SERVICE_HANDLE_T handle,
 		VCHIQ_SERVICE_STATS_INC(service, bulk_stalls);
 		do {
 			mutex_unlock(&service->bulk_mutex);
-			if (wait_for_completion_killable(
+			if (wait_for_completion_interruptible(
 						&service->bulk_remove_event)) {
 				status = VCHIQ_RETRY;
 				goto error_exit;
@@ -3145,7 +3146,7 @@ VCHIQ_STATUS_T vchiq_bulk_transfer(VCHIQ_SERVICE_HANDLE_T handle,
 
 	if (bulk_waiter) {
 		bulk_waiter->bulk = bulk;
-		if (wait_for_completion_killable(&bulk_waiter->event))
+		if (wait_for_completion_interruptible(&bulk_waiter->event))
 			status = VCHIQ_RETRY;
 		else if (bulk_waiter->actual == VCHIQ_BULK_ACTUAL_ABORTED)
 			status = VCHIQ_ERROR;
diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_util.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_util.c
index 55c5fd82b911..30deea1b57f7 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_util.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_util.c
@@ -80,7 +80,7 @@ void vchiu_queue_push(struct vchiu_queue *queue, struct vchiq_header *header)
 		return;
 
 	while (queue->write == queue->read + queue->size) {
-		if (wait_for_completion_killable(&queue->pop))
+		if (wait_for_completion_interruptible(&queue->pop))
 			flush_signals(current);
 	}
 
@@ -93,7 +93,7 @@ void vchiu_queue_push(struct vchiu_queue *queue, struct vchiq_header *header)
 struct vchiq_header *vchiu_queue_peek(struct vchiu_queue *queue)
 {
 	while (queue->write == queue->read) {
-		if (wait_for_completion_killable(&queue->push))
+		if (wait_for_completion_interruptible(&queue->push))
 			flush_signals(current);
 	}
 
@@ -107,7 +107,7 @@ struct vchiq_header *vchiu_queue_pop(struct vchiu_queue *queue)
 	struct vchiq_header *header;
 
 	while (queue->write == queue->read) {
-		if (wait_for_completion_killable(&queue->push))
+		if (wait_for_completion_interruptible(&queue->push))
 			flush_signals(current);
 	}
 
-- 
2.21.0

From 4d0d97ce18dc90a3ca6296ee669c51b5a55a61c7 Mon Sep 17 00:00:00 2001
From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Date: Thu, 9 May 2019 16:31:35 +0200
Subject: [PATCH 3/4] staging: vchiq: make wait events interruptible

The killable version of wait_event() is meant to be used on situations
where it should not fail at all costs, but still have the convenience of
being able to kill it if really necessary. Wait events in VCHIQ doesn't
fit this criteria, as it's mainly used as an interface to V4L2 and ALSA
devices.

Fixes: 852b2876a8a8 ("staging: vchiq: rework remove_event handling")
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---
 .../vc04_services/interface/vchiq_arm/vchiq_core.c     | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
index bc5661dde987..0958d86aebe6 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
@@ -425,13 +425,21 @@ remote_event_create(wait_queue_head_t *wq, struct remote_event *event)
 	init_waitqueue_head(wq);
 }
 
+/*
+ * All the event waiting routines in VCHIQ used a custom semaphore
+ * implementation that filtered most signals. This achieved a behaviour similar
+ * to the "killable" family of functions. While cleaning up this code all the
+ * routines where switched to the "interruptible" family of functions, as the
+ * former was deemed unjustified and the use "killable" set all VCHIQ's
+ * threads in D state.
+ */
 static inline int
 remote_event_wait(wait_queue_head_t *wq, struct remote_event *event)
 {
 	if (!event->fired) {
 		event->armed = 1;
 		dsb(sy);
-		if (wait_event_killable(*wq, event->fired)) {
+		if (wait_event_interruptible(*wq, event->fired)) {
 			event->armed = 0;
 			return 0;
 		}
-- 
2.21.0

From e4d9fccaaf6e61bbc7416d92d73cec5a5f0cb458 Mon Sep 17 00:00:00 2001
From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Date: Thu, 9 May 2019 16:31:36 +0200
Subject: [PATCH 4/4] staging: vchiq: stop explicitly comparing with zero to
 catch errors

The vchiq code tends to follow a coding pattern that's not accepted as
per the Linux kernel coding style

We have this:
	if (expression != 0)

We want this:
	if (expression)

We make an exception if the expression refers to a size, in which case
it's accepted for the sake of clarity.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---
 .../bcm2835-camera/bcm2835-camera.c           | 11 ++--
 .../interface/vchiq_arm/vchiq_2835_arm.c      |  2 +-
 .../interface/vchiq_arm/vchiq_arm.c           | 66 ++++++++-----------
 .../interface/vchiq_arm/vchiq_connected.c     |  4 +-
 .../interface/vchiq_arm/vchiq_core.c          | 28 ++++----
 .../interface/vchiq_arm/vchiq_debugfs.c       |  4 +-
 6 files changed, 52 insertions(+), 63 deletions(-)

diff --git a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
index 7c6cf41645eb..c5b29a28d326 100644
--- a/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
+++ b/drivers/staging/vc04_services/bcm2835-camera/bcm2835-camera.c
@@ -328,7 +328,7 @@ static void buffer_cb(struct vchiq_mmal_instance *instance,
 		 "%s: status:%d, buf:%p, length:%lu, flags %u, pts %lld\n",
 		 __func__, status, buf, length, mmal_flags, pts);
 
-	if (status != 0) {
+	if (status) {
 		/* error in transfer */
 		if (buf) {
 			/* there was a buffer with the error so return it */
@@ -360,8 +360,7 @@ static void buffer_cb(struct vchiq_mmal_instance *instance,
 		}
 	} else {
 		if (dev->capture.frame_count) {
-			if (dev->capture.vc_start_timestamp != -1 &&
-			    pts != 0) {
+			if (dev->capture.vc_start_timestamp != -1 && pts) {
 				ktime_t timestamp;
 				s64 runtime_us = pts -
 				    dev->capture.vc_start_timestamp;
@@ -829,7 +828,7 @@ static int vidioc_enum_input(struct file *file, void *priv,
 			     struct v4l2_input *inp)
 {
 	/* only a single camera input */
-	if (inp->index != 0)
+	if (inp->index)
 		return -EINVAL;
 
 	inp->type = V4L2_INPUT_TYPE_CAMERA;
@@ -845,7 +844,7 @@ static int vidioc_g_input(struct file *file, void *priv, unsigned int *i)
 
 static int vidioc_s_input(struct file *file, void *priv, unsigned int i)
 {
-	if (i != 0)
+	if (i)
 		return -EINVAL;
 
 	return 0;
@@ -1291,7 +1290,7 @@ static int vidioc_s_fmt_vid_cap(struct file *file, void *priv,
 	}
 
 	ret = mmal_setup_components(dev, f);
-	if (ret != 0) {
+	if (ret) {
 		v4l2_err(&dev->v4l2_dev,
 			 "%s: failed to setup mmal components: %d\n",
 			 __func__, ret);
diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
index 833b28e9ba4b..e87d6e290a9f 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
@@ -553,7 +553,7 @@ create_pagelist(char __user *buf, size_t count, unsigned short type)
 		(g_cache_line_size - 1)))) {
 		char *fragments;
 
-		if (down_interruptible(&g_free_fragments_sema) != 0) {
+		if (down_interruptible(&g_free_fragments_sema)) {
 			cleanup_pagelistinfo(pagelistinfo);
 			return NULL;
 		}
diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
index ccfb8218b83c..934014cf08b2 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
@@ -266,7 +266,7 @@ VCHIQ_STATUS_T vchiq_shutdown(VCHIQ_INSTANCE_T instance)
 	vchiq_log_trace(vchiq_core_log_level,
 		"%s(%p) called", __func__, instance);
 
-	if (mutex_lock_killable(&state->mutex) != 0)
+	if (mutex_lock_killable(&state->mutex))
 		return VCHIQ_RETRY;
 
 	/* Remove all services */
@@ -308,7 +308,7 @@ VCHIQ_STATUS_T vchiq_connect(VCHIQ_INSTANCE_T instance)
 	vchiq_log_trace(vchiq_core_log_level,
 		"%s(%p) called", __func__, instance);
 
-	if (mutex_lock_killable(&state->mutex) != 0) {
+	if (mutex_lock_killable(&state->mutex)) {
 		vchiq_log_trace(vchiq_core_log_level,
 			"%s: call to mutex_lock failed", __func__);
 		status = VCHIQ_RETRY;
@@ -673,8 +673,7 @@ service_callback(VCHIQ_REASON_T reason, struct vchiq_header *header,
 
 			DEBUG_TRACE(SERVICE_CALLBACK_LINE);
 			if (wait_for_completion_interruptible(
-						&user_service->remove_event)
-				!= 0) {
+						&user_service->remove_event)) {
 				vchiq_log_info(vchiq_arm_log_level,
 					"%s interrupted", __func__);
 				DEBUG_TRACE(SERVICE_CALLBACK_LINE);
@@ -878,7 +877,7 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 			break;
 		}
 		rc = mutex_lock_killable(&instance->state->mutex);
-		if (rc != 0) {
+		if (rc) {
 			vchiq_log_error(vchiq_arm_log_level,
 				"vchiq: connect: could not lock mutex for "
 				"state %d: %d",
@@ -902,9 +901,8 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		void *userdata;
 		int srvstate;
 
-		if (copy_from_user
-			 (&args, (const void __user *)arg,
-			  sizeof(args)) != 0) {
+		if (copy_from_user(&args, (const void __user *)arg,
+				   sizeof(args))) {
 			ret = -EFAULT;
 			break;
 		}
@@ -968,7 +966,7 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 				&(((struct vchiq_create_service __user *)
 					arg)->handle),
 				(const void *)&service->handle,
-				sizeof(service->handle)) != 0) {
+				sizeof(service->handle))) {
 				ret = -EFAULT;
 				vchiq_remove_service(service->handle);
 			}
@@ -1043,9 +1041,8 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	case VCHIQ_IOC_QUEUE_MESSAGE: {
 		struct vchiq_queue_message args;
 
-		if (copy_from_user
-			 (&args, (const void __user *)arg,
-			  sizeof(args)) != 0) {
+		if (copy_from_user(&args, (const void __user *)arg,
+				   sizeof(args))) {
 			ret = -EFAULT;
 			break;
 		}
@@ -1077,9 +1074,8 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 			(cmd == VCHIQ_IOC_QUEUE_BULK_TRANSMIT) ?
 			VCHIQ_BULK_TRANSMIT : VCHIQ_BULK_RECEIVE;
 
-		if (copy_from_user
-			(&args, (const void __user *)arg,
-			sizeof(args)) != 0) {
+		if (copy_from_user(&args, (const void __user *)arg,
+				   sizeof(args))) {
 			ret = -EFAULT;
 			break;
 		}
@@ -1153,7 +1149,7 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 				&(((struct vchiq_queue_bulk_transfer __user *)
 					arg)->mode),
 				(const void *)&mode_waiting,
-				sizeof(mode_waiting)) != 0)
+				sizeof(mode_waiting)))
 				ret = -EFAULT;
 		}
 	} break;
@@ -1168,7 +1164,7 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		}
 
 		if (copy_from_user(&args, (const void __user *)arg,
-			sizeof(args)) != 0) {
+			sizeof(args))) {
 			ret = -EFAULT;
 			break;
 		}
@@ -1186,7 +1182,7 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 			rc = wait_for_completion_interruptible(
 						&instance->insert_event);
 			mutex_lock(&instance->completion_mutex);
-			if (rc != 0) {
+			if (rc) {
 				DEBUG_TRACE(AWAIT_COMPLETION_LINE);
 				vchiq_log_info(vchiq_arm_log_level,
 					"AWAIT_COMPLETION interrupted");
@@ -1252,7 +1248,7 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 					if (copy_from_user(&msgbuf,
 						(const void __user *)
 						&args.msgbufs[msgbufcount],
-						sizeof(msgbuf)) != 0) {
+						sizeof(msgbuf))) {
 						if (ret == 0)
 							ret = -EFAULT;
 						break;
@@ -1260,7 +1256,7 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 
 					/* Copy the message to user space */
 					if (copy_to_user(msgbuf, header,
-						msglen) != 0) {
+						msglen)) {
 						if (ret == 0)
 							ret = -EFAULT;
 						break;
@@ -1285,8 +1281,7 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 					(size_t)args.buf + ret *
 					sizeof(struct vchiq_completion_data)),
 					completion,
-					sizeof(struct vchiq_completion_data))
-									!= 0) {
+					sizeof(struct vchiq_completion_data))) {
 						if (ret == 0)
 							ret = -EFAULT;
 					break;
@@ -1306,13 +1301,13 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 					&((struct vchiq_await_completion *)arg)
 						->msgbufcount,
 					&msgbufcount,
-					sizeof(msgbufcount)) != 0) {
+					sizeof(msgbufcount))) {
 					ret = -EFAULT;
 				}
 			}
 		}
 
-		if (ret != 0)
+		if (ret)
 			complete(&instance->remove_event);
 		mutex_unlock(&instance->completion_mutex);
 		DEBUG_TRACE(AWAIT_COMPLETION_LINE);
@@ -1324,9 +1319,8 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		struct vchiq_header *header;
 
 		DEBUG_TRACE(DEQUEUE_MESSAGE_LINE);
-		if (copy_from_user
-			 (&args, (const void __user *)arg,
-			  sizeof(args)) != 0) {
+		if (copy_from_user(&args, (const void __user *)arg,
+				   sizeof(args))) {
 			ret = -EFAULT;
 			break;
 		}
@@ -1412,7 +1406,7 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		struct vchiq_config config;
 
 		if (copy_from_user(&args, (const void __user *)arg,
-			sizeof(args)) != 0) {
+				   sizeof(args))) {
 			ret = -EFAULT;
 			break;
 		}
@@ -1431,9 +1425,8 @@ vchiq_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	case VCHIQ_IOC_SET_SERVICE_OPTION: {
 		struct vchiq_set_service_option args;
 
-		if (copy_from_user(
-			&args, (const void __user *)arg,
-			sizeof(args)) != 0) {
+		if (copy_from_user(&args, (const void __user *)arg,
+				   sizeof(args))) {
 			ret = -EFAULT;
 			break;
 		}
@@ -2361,8 +2354,7 @@ vchiq_keepalive_thread_func(void *v)
 	while (1) {
 		long rc = 0, uc = 0;
 
-		if (wait_for_completion_interruptible(&arm_state->ka_evt)
-				!= 0) {
+		if (wait_for_completion_interruptible(&arm_state->ka_evt)) {
 			vchiq_log_error(vchiq_susp_log_level,
 				"%s interrupted", __func__);
 			flush_signals(current);
@@ -3043,7 +3035,7 @@ vchiq_use_internal(struct vchiq_state *state, struct vchiq_service *service,
 			vchiq_log_info(vchiq_susp_log_level, "%s %s resume "
 				"blocked - waiting...", __func__, entity);
 			if (wait_for_completion_killable(
-					&arm_state->resume_blocker) != 0) {
+					&arm_state->resume_blocker)) {
 				vchiq_log_error(vchiq_susp_log_level, "%s %s "
 					"wait for resume blocker interrupted",
 					__func__, entity);
@@ -3092,7 +3084,7 @@ vchiq_use_internal(struct vchiq_state *state, struct vchiq_service *service,
 		vchiq_log_info(vchiq_susp_log_level, "%s %s wait for resume",
 			__func__, entity);
 		if (wait_for_completion_killable(
-				&arm_state->vc_resume_complete) != 0) {
+				&arm_state->vc_resume_complete)) {
 			vchiq_log_error(vchiq_susp_log_level, "%s %s wait for "
 				"resume interrupted", __func__, entity);
 			ret = VCHIQ_ERROR;
@@ -3537,13 +3529,13 @@ static int vchiq_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, drvdata);
 
 	err = vchiq_platform_init(pdev, &g_state);
-	if (err != 0)
+	if (err)
 		goto failed_platform_init;
 
 	cdev_init(&vchiq_cdev, &vchiq_fops);
 	vchiq_cdev.owner = THIS_MODULE;
 	err = cdev_add(&vchiq_cdev, vchiq_devid, 1);
-	if (err != 0) {
+	if (err) {
 		vchiq_log_error(vchiq_arm_log_level,
 			"Unable to register device");
 		goto failed_platform_init;
diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_connected.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_connected.c
index 7d64e2ed7b42..5bcb6396b23b 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_connected.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_connected.c
@@ -71,7 +71,7 @@ void vchiq_add_connected_callback(VCHIQ_CONNECTED_CALLBACK_T callback)
 {
 	connected_init();
 
-	if (mutex_lock_killable(&g_connected_mutex) != 0)
+	if (mutex_lock_killable(&g_connected_mutex))
 		return;
 
 	if (g_connected)
@@ -106,7 +106,7 @@ void vchiq_call_connected_callbacks(void)
 
 	connected_init();
 
-	if (mutex_lock_killable(&g_connected_mutex) != 0)
+	if (mutex_lock_killable(&g_connected_mutex))
 		return;
 
 	for (i = 0; i <  g_num_deferred_callbacks; i++)
diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
index 0958d86aebe6..bbdf16977afb 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
@@ -830,7 +830,7 @@ queue_message(struct vchiq_state *state, struct vchiq_service *service,
 	WARN_ON(!(stride <= VCHIQ_SLOT_SIZE));
 
 	if (!(flags & QMFLAGS_NO_MUTEX_LOCK) &&
-		(mutex_lock_killable(&state->slot_mutex) != 0))
+	    mutex_lock_killable(&state->slot_mutex))
 		return VCHIQ_RETRY;
 
 	if (type == VCHIQ_MSG_DATA) {
@@ -842,8 +842,8 @@ queue_message(struct vchiq_state *state, struct vchiq_service *service,
 			return VCHIQ_ERROR;
 		}
 
-		WARN_ON((flags & (QMFLAGS_NO_MUTEX_LOCK |
-				  QMFLAGS_NO_MUTEX_UNLOCK)) != 0);
+		WARN_ON(flags & (QMFLAGS_NO_MUTEX_LOCK |
+				 QMFLAGS_NO_MUTEX_UNLOCK));
 
 		if (service->closing) {
 			/* The service has been closed */
@@ -904,7 +904,7 @@ queue_message(struct vchiq_state *state, struct vchiq_service *service,
 				return VCHIQ_RETRY;
 			if (service->closing)
 				return VCHIQ_ERROR;
-			if (mutex_lock_killable(&state->slot_mutex) != 0)
+			if (mutex_lock_killable(&state->slot_mutex))
 				return VCHIQ_RETRY;
 			if (service->srvstate != VCHIQ_SRVSTATE_OPEN) {
 				/* The service has been closed */
@@ -942,8 +942,8 @@ queue_message(struct vchiq_state *state, struct vchiq_service *service,
 			header, size, VCHIQ_MSG_SRCPORT(msgid),
 			VCHIQ_MSG_DSTPORT(msgid));
 
-		WARN_ON((flags & (QMFLAGS_NO_MUTEX_LOCK |
-				  QMFLAGS_NO_MUTEX_UNLOCK)) != 0);
+		WARN_ON(flags & (QMFLAGS_NO_MUTEX_LOCK |
+				 QMFLAGS_NO_MUTEX_UNLOCK));
 
 		callback_result =
 			copy_message_data(copy_callback, context,
@@ -1070,8 +1070,8 @@ queue_message_sync(struct vchiq_state *state, struct vchiq_service *service,
 
 	local = state->local;
 
-	if ((VCHIQ_MSG_TYPE(msgid) != VCHIQ_MSG_RESUME) &&
-		(mutex_lock_killable(&state->sync_mutex) != 0))
+	if (VCHIQ_MSG_TYPE(msgid) != VCHIQ_MSG_RESUME &&
+	    mutex_lock_killable(&state->sync_mutex))
 		return VCHIQ_RETRY;
 
 	remote_event_wait(&state->sync_release_event, &local->sync_release);
@@ -1748,8 +1748,7 @@ parse_rx_slots(struct vchiq_state *state)
 					&service->bulk_rx : &service->bulk_tx;
 
 				DEBUG_TRACE(PARSE_LINE);
-				if (mutex_lock_killable(
-					&service->bulk_mutex) != 0) {
+				if (mutex_lock_killable(&service->bulk_mutex)) {
 					DEBUG_TRACE(PARSE_LINE);
 					goto bail_not_ready;
 				}
@@ -2553,7 +2552,7 @@ do_abort_bulks(struct vchiq_service *service)
 	VCHIQ_STATUS_T status;
 
 	/* Abort any outstanding bulk transfers */
-	if (mutex_lock_killable(&service->bulk_mutex) != 0)
+	if (mutex_lock_killable(&service->bulk_mutex))
 		return 0;
 	abort_outstanding_bulks(service, &service->bulk_tx);
 	abort_outstanding_bulks(service, &service->bulk_rx);
@@ -3068,7 +3067,7 @@ VCHIQ_STATUS_T vchiq_bulk_transfer(VCHIQ_SERVICE_HANDLE_T handle,
 	queue = (dir == VCHIQ_BULK_TRANSMIT) ?
 		&service->bulk_tx : &service->bulk_rx;
 
-	if (mutex_lock_killable(&service->bulk_mutex) != 0) {
+	if (mutex_lock_killable(&service->bulk_mutex)) {
 		status = VCHIQ_RETRY;
 		goto error_exit;
 	}
@@ -3082,8 +3081,7 @@ VCHIQ_STATUS_T vchiq_bulk_transfer(VCHIQ_SERVICE_HANDLE_T handle,
 				status = VCHIQ_RETRY;
 				goto error_exit;
 			}
-			if (mutex_lock_killable(&service->bulk_mutex)
-				!= 0) {
+			if (mutex_lock_killable(&service->bulk_mutex)) {
 				status = VCHIQ_RETRY;
 				goto error_exit;
 			}
@@ -3111,7 +3109,7 @@ VCHIQ_STATUS_T vchiq_bulk_transfer(VCHIQ_SERVICE_HANDLE_T handle,
 
 	/* The slot mutex must be held when the service is being closed, so
 	   claim it here to ensure that isn't happening */
-	if (mutex_lock_killable(&state->slot_mutex) != 0) {
+	if (mutex_lock_killable(&state->slot_mutex)) {
 		status = VCHIQ_RETRY;
 		goto cancel_bulk_error_exit;
 	}
diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_debugfs.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_debugfs.c
index 3928287cf5f7..8799c30f397c 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_debugfs.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_debugfs.c
@@ -114,7 +114,7 @@ static ssize_t debugfs_log_write(struct file *file,
 	if (count >= DEBUGFS_WRITE_BUF_SIZE)
 		count = DEBUGFS_WRITE_BUF_SIZE;
 
-	if (copy_from_user(kbuf, buffer, count) != 0)
+	if (copy_from_user(kbuf, buffer, count))
 		return -EFAULT;
 	kbuf[count - 1] = 0;
 
@@ -179,7 +179,7 @@ static ssize_t debugfs_trace_write(struct file *file,
 	VCHIQ_INSTANCE_T instance = f->private;
 	char firstchar;
 
-	if (copy_from_user(&firstchar, buffer, 1) != 0)
+	if (copy_from_user(&firstchar, buffer, 1))
 		return -EFAULT;
 
 	switch (firstchar) {
-- 
2.21.0