Commit c22502cb authored by Umang Jain's avatar Umang Jain Committed by Greg Kroah-Hartman
Browse files

staging: vchiq_core: Bubble up wait_event_interruptible() return value 



wait_event_interruptible() returns if the condition evaluates to true
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.

Meanwhile at it, remote_wait_event() is modified to return 0 on success,
and an error code (from wait_event_interruptible()) on failure. The
return value is now checked for remote_wait_event() calls.

Signed-off-by: default avatarUmang Jain <umang.jain@ideasonboard.com>
Tested-by: default avatarStefan Wahren <wahrenst@gmx.net>
Link: https://lore.kernel.org/r/20240703131052.597443-2-umang.jain@ideasonboard.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d3401cef

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c

+24 −7
Original line number Diff line number Diff line
@@ -501,16 +501,21 @@ remote_event_create(wait_queue_head_t *wq, struct remote_event *event) 
 * 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.

 *

 * Returns: 0 on success, a negative error code on failure

 */

static inline int

remote_event_wait(wait_queue_head_t *wq, struct remote_event *event)

{

	int ret = 0;



	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). */
@@ -518,7 +523,7 @@ remote_event_wait(wait_queue_head_t *wq, struct remote_event *event) 
	}



	event->fired = 0;

	return 1;

	return ret;

}



/*
@@ -1140,6 +1145,7 @@ 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 +1153,9 @@ 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)

		return ret;



	/* Ensure that reads don't overtake the remote_event_wait. */

	rmb();
@@ -1929,13 +1937,16 @@ 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)

			return ret;



		/* Ensure that reads don't overtake the remote_event_wait. */

		rmb();
@@ -1966,6 +1977,7 @@ 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 +1987,9 @@ 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)

			return ret;



		process_free_queue(state, found, length);

	}
@@ -1992,6 +2006,7 @@ 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 +2014,9 @@ 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)

			return ret;



		/* Ensure that reads don't overtake the remote_event_wait. */

		rmb();