[PATCH 1/2] staging: vchiq_core: Bubble up wait_event_interruptible() return value

[Umang Jain <umang.jain@xxxxxxxxxxxxxxxx>]

wait_event_interruptible() can return if the condition evaluates to
true or it receives a signal. However, the current code always assume
that the wait_event_interruptible() returns only when the event is
fired. This should not be the case as wait_event_interruptible() can
return on receiving a signal (with -ERESTARTSYS as return value).

We should consider this and bubble up the return value of
wait_event_interruptible() to exactly know if the wait has failed
and error out. This will also help to properly stop kthreads in the
subsequent patch.

Signed-off-by: Umang Jain <umang.jain@xxxxxxxxxxxxxxxx>
---
 .../interface/vchiq_arm/vchiq_core.c          | 27 ++++++++++++++-----
 1 file changed, 21 insertions(+), 6 deletions(-)

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 4f65e4021c4d..b5f5853924a8 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
@@ -505,12 +505,15 @@ remote_event_create(wait_queue_head_t *wq, struct remote_event *event)
 static inline int
 remote_event_wait(wait_queue_head_t *wq, struct remote_event *event)
 {
+	int ret;
+
 	if (!event->fired) {
 		event->armed = 1;
 		dsb(sy);
-		if (wait_event_interruptible(*wq, event->fired)) {
+		ret = wait_event_interruptible(*wq, event->fired);
+		if (ret) {
 			event->armed = 0;
-			return 0;
+			return ret;
 		}
 		event->armed = 0;
 		/* Ensure that the peer sees that we are not waiting (armed == 0). */
@@ -1140,6 +1143,7 @@ queue_message_sync(struct vchiq_state *state, struct vchiq_service *service,
 	struct vchiq_header *header;
 	ssize_t callback_result;
 	int svc_fourcc;
+	int ret;
 
 	local = state->local;
 
@@ -1147,7 +1151,9 @@ queue_message_sync(struct vchiq_state *state, struct vchiq_service *service,
 	    mutex_lock_killable(&state->sync_mutex))
 		return -EAGAIN;
 
-	remote_event_wait(&state->sync_release_event, &local->sync_release);
+	ret = remote_event_wait(&state->sync_release_event, &local->sync_release);
+	if (ret < 0)
+		return ret;
 
 	/* Ensure that reads don't overtake the remote_event_wait. */
 	rmb();
@@ -1929,13 +1935,16 @@ slot_handler_func(void *v)
 {
 	struct vchiq_state *state = v;
 	struct vchiq_shared_state *local = state->local;
+	int ret;
 
 	DEBUG_INITIALISE(local);
 
 	while (1) {
 		DEBUG_COUNT(SLOT_HANDLER_COUNT);
 		DEBUG_TRACE(SLOT_HANDLER_LINE);
-		remote_event_wait(&state->trigger_event, &local->trigger);
+		ret = remote_event_wait(&state->trigger_event, &local->trigger);
+		if (ret < 0)
+			return ret;
 
 		/* Ensure that reads don't overtake the remote_event_wait. */
 		rmb();
@@ -1966,6 +1975,7 @@ recycle_func(void *v)
 	struct vchiq_shared_state *local = state->local;
 	u32 *found;
 	size_t length;
+	int ret;
 
 	length = sizeof(*found) * BITSET_SIZE(VCHIQ_MAX_SERVICES);
 
@@ -1975,7 +1985,9 @@ recycle_func(void *v)
 		return -ENOMEM;
 
 	while (1) {
-		remote_event_wait(&state->recycle_event, &local->recycle);
+		ret = remote_event_wait(&state->recycle_event, &local->recycle);
+		if (ret < 0)
+			return ret;
 
 		process_free_queue(state, found, length);
 	}
@@ -1992,6 +2004,7 @@ sync_func(void *v)
 		(struct vchiq_header *)SLOT_DATA_FROM_INDEX(state,
 			state->remote->slot_sync);
 	int svc_fourcc;
+	int ret;
 
 	while (1) {
 		struct vchiq_service *service;
@@ -1999,7 +2012,9 @@ sync_func(void *v)
 		int type;
 		unsigned int localport, remoteport;
 
-		remote_event_wait(&state->sync_trigger_event, &local->sync_trigger);
+		ret = remote_event_wait(&state->sync_trigger_event, &local->sync_trigger);
+		if (ret < 0)
+			return ret;
 
 		/* Ensure that reads don't overtake the remote_event_wait. */
 		rmb();
-- 
2.43.0