Commit 36022f3e authored by Umang Jain's avatar Umang Jain Committed by Greg Kroah-Hartman
Browse files

staging: vchiq_core: Use killable wait completions for bulk transfers 

commit f27e47bc ("staging: vchiq: use completions instead of
semaphores") introduced completions for events in vchiq interface.
It introduced _interruptible() version of completions for waiting
on events. However, it missed a subtle down_interruptible() macro
override in vchiq_killable.h, which used to mask most of the signals
and only interrupt on fatal ones.

The above issue was fixed in commit a772f116 ("staging: vchiq: switch
to wait_for_completion_killable"). Given the override logic of
down_interruptible() that existed in vchiq_killable.h, that commit
fixed the completions with the correct variation i.e. killable() family
of functions.

However, commit a772f116 ("staging: vchiq: switch to
wait_for_completion_killable") later got reverted [1] due to high CPU
load noticed by various downstream and upstream distributions [2].
Reverting the commit solved this problem but the root cause was never
diagonsed and the entire commit was reverted.

This patch brings back killable version of wait events but only for
bulk transfers and queue_message() transfer code paths.

The idea is to bring back killable versions for various event
completions in a phased manner so that we do not re-regress again as
noticed in [2]. Hence, no other wait events are converted from
interruptible -> killable in this patch.

Since the bulk transfers are no longer interruptible (but killable),
drop the "_interruptible" suffix from all vchiq_bulk_xfer_* functions.

[1]: commit 086efbab ("staging: vchiq: revert "switch to wait_for_completion_killable"")
[2]: https://patchwork.kernel.org/project/linux-arm-kernel/cover/20190509143137.31254-1-nsaenzjulienne@suse.de/



Signed-off-by: default avatarUmang Jain <umang.jain@ideasonboard.com>
Link: https://lore.kernel.org/r/20240918163100.870596-2-umang.jain@ideasonboard.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 00ea2b0d

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

+7 −10
Original line number Diff line number Diff line
@@ -857,9 +857,8 @@ vchiq_bulk_transmit(struct vchiq_instance *instance, unsigned int handle, const 
		switch (mode) {

		case VCHIQ_BULK_MODE_NOCALLBACK:

		case VCHIQ_BULK_MODE_CALLBACK:

			ret = vchiq_bulk_xfer_callback_interruptible(instance, handle,

								     (void *)data, NULL,

								     size, mode, userdata,

			ret = vchiq_bulk_xfer_callback(instance, handle, (void *)data,

						       NULL, size, mode, userdata,

						       VCHIQ_BULK_TRANSMIT);

			break;

		case VCHIQ_BULK_MODE_BLOCKING:
@@ -895,10 +894,8 @@ int vchiq_bulk_receive(struct vchiq_instance *instance, unsigned int handle, 
		switch (mode) {

		case VCHIQ_BULK_MODE_NOCALLBACK:

		case VCHIQ_BULK_MODE_CALLBACK:

			ret = vchiq_bulk_xfer_callback_interruptible(instance, handle,

								     (void *)data, NULL,

								     size, mode, userdata,

								     VCHIQ_BULK_RECEIVE);

			ret = vchiq_bulk_xfer_callback(instance, handle, (void *)data, NULL,

						       size, mode, userdata, VCHIQ_BULK_RECEIVE);

			break;

		case VCHIQ_BULK_MODE_BLOCKING:

			ret = vchiq_blocking_bulk_transfer(instance, handle, (void *)data, size,
@@ -969,7 +966,7 @@ vchiq_blocking_bulk_transfer(struct vchiq_instance *instance, unsigned int handl 
			return -ENOMEM;

	}



	ret = vchiq_bulk_xfer_blocking_interruptible(instance, handle, data, NULL, size,

	ret = vchiq_bulk_xfer_blocking(instance, handle, data, NULL, size,

				       &waiter->bulk_waiter, dir);

	if ((ret != -EAGAIN) || fatal_signal_pending(current) || !waiter->bulk_waiter.bulk) {

		struct vchiq_bulk *bulk = waiter->bulk_waiter.bulk;

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

+23 −23
Original line number Diff line number Diff line
@@ -962,7 +962,7 @@ queue_message(struct vchiq_state *state, struct vchiq_service *service, 
			spin_unlock(&state->quota_spinlock);

			mutex_unlock(&state->slot_mutex);



			if (wait_for_completion_interruptible(&state->data_quota_event))

			if (wait_for_completion_killable(&state->data_quota_event))

				return -EAGAIN;



			mutex_lock(&state->slot_mutex);
@@ -986,7 +986,7 @@ queue_message(struct vchiq_state *state, struct vchiq_service *service, 
				quota->message_use_count, quota->slot_use_count);

			VCHIQ_SERVICE_STATS_INC(service, quota_stalls);

			mutex_unlock(&state->slot_mutex);

			if (wait_for_completion_interruptible(&quota->quota_event))

			if (wait_for_completion_killable(&quota->quota_event))

				return -EAGAIN;

			if (service->closing)

				return -EHOSTDOWN;
@@ -2662,7 +2662,7 @@ close_service_complete(struct vchiq_service *service, int failstate) 
 * returned to user context.

 */

static int

vchiq_bulk_xfer_queue_msg_interruptible(struct vchiq_service *service,

vchiq_bulk_xfer_queue_msg_killable(struct vchiq_service *service,

				   void *offset, void __user *uoffset,

				   int size, void *userdata,

				   enum vchiq_bulk_mode mode,
@@ -2695,7 +2695,7 @@ vchiq_bulk_xfer_queue_msg_interruptible(struct vchiq_service *service, 
		VCHIQ_SERVICE_STATS_INC(service, bulk_stalls);

		do {

			mutex_unlock(&service->bulk_mutex);

			if (wait_for_completion_interruptible(&service->bulk_remove_event))

			if (wait_for_completion_killable(&service->bulk_remove_event))

				return -EAGAIN;

			if (mutex_lock_killable(&service->bulk_mutex))

				return -EAGAIN;
@@ -2763,7 +2763,7 @@ vchiq_bulk_xfer_queue_msg_interruptible(struct vchiq_service *service, 


        if (bulk_waiter) {

                bulk_waiter->bulk = bulk;

                if (wait_for_completion_interruptible(&bulk_waiter->event))

		if (wait_for_completion_killable(&bulk_waiter->event))

                        status = -EAGAIN;

                else if (bulk_waiter->actual == VCHIQ_BULK_ACTUAL_ABORTED)

                        status = -EINVAL;
@@ -3105,7 +3105,7 @@ vchiq_remove_service(struct vchiq_instance *instance, unsigned int handle) 
}



int

vchiq_bulk_xfer_blocking_interruptible(struct vchiq_instance *instance, unsigned int handle,

vchiq_bulk_xfer_blocking(struct vchiq_instance *instance, unsigned int handle,

			 void *offset, void __user *uoffset, int size,

			 void __user *userdata, enum vchiq_bulk_dir dir)

{
@@ -3126,7 +3126,7 @@ vchiq_bulk_xfer_blocking_interruptible(struct vchiq_instance *instance, unsigned 
		goto error_exit;





	status = vchiq_bulk_xfer_queue_msg_interruptible(service, offset, uoffset, size,

	status = vchiq_bulk_xfer_queue_msg_killable(service, offset, uoffset, size,

						    userdata, mode, dir);



error_exit:
@@ -3136,7 +3136,7 @@ vchiq_bulk_xfer_blocking_interruptible(struct vchiq_instance *instance, unsigned 
}



int

vchiq_bulk_xfer_callback_interruptible(struct vchiq_instance *instance, unsigned int handle,

vchiq_bulk_xfer_callback(struct vchiq_instance *instance, unsigned int handle,

			 void *offset, void __user *uoffset, int size,

			 enum vchiq_bulk_mode mode, void *userdata,

			 enum vchiq_bulk_dir dir)
@@ -3160,7 +3160,7 @@ vchiq_bulk_xfer_callback_interruptible(struct vchiq_instance *instance, unsigned 
	if (vchiq_check_service(service))

		goto error_exit;



	status = vchiq_bulk_xfer_queue_msg_interruptible(service, offset, uoffset,

	status = vchiq_bulk_xfer_queue_msg_killable(service, offset, uoffset,

						    size, userdata, mode, dir);



error_exit:
@@ -3175,7 +3175,7 @@ vchiq_bulk_xfer_callback_interruptible(struct vchiq_instance *instance, unsigned 
 * and the call should be retried after being returned to user context.

 */

int

vchiq_bulk_xfer_waiting_interruptible(struct vchiq_instance *instance,

vchiq_bulk_xfer_waiting(struct vchiq_instance *instance,

			unsigned int handle, struct bulk_waiter *userdata)

{

	struct vchiq_service *service = find_service_by_handle(instance, handle);
@@ -3200,7 +3200,7 @@ vchiq_bulk_xfer_waiting_interruptible(struct vchiq_instance *instance, 


	status = 0;



	if (wait_for_completion_interruptible(&bulk_waiter->event))

	if (wait_for_completion_killable(&bulk_waiter->event))

		return -EAGAIN;

	else if (bulk_waiter->actual == VCHIQ_BULK_ACTUAL_ABORTED)

		return -EINVAL;

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

+9 −9
Original line number Diff line number Diff line
@@ -471,16 +471,16 @@ extern void 
remote_event_pollall(struct vchiq_state *state);



extern int

vchiq_bulk_xfer_waiting_interruptible(struct vchiq_instance *instance,

				      unsigned int handle, struct bulk_waiter *userdata);

vchiq_bulk_xfer_waiting(struct vchiq_instance *instance, unsigned int handle,

			struct bulk_waiter *userdata);



extern int

vchiq_bulk_xfer_blocking_interruptible(struct vchiq_instance *instance, unsigned int handle,

vchiq_bulk_xfer_blocking(struct vchiq_instance *instance, unsigned int handle,

			 void *offset, void __user *uoffset, int size,

			 void __user *userdata, enum vchiq_bulk_dir dir);



extern int

vchiq_bulk_xfer_callback_interruptible(struct vchiq_instance *instance, unsigned int handle,

vchiq_bulk_xfer_callback(struct vchiq_instance *instance, unsigned int handle,

			 void *offset, void __user *uoffset, int size,

			 enum vchiq_bulk_mode mode, void *userdata,

			 enum vchiq_bulk_dir dir);

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

+7 −7
Original line number Diff line number Diff line
@@ -305,7 +305,7 @@ static int vchiq_irq_queue_bulk_tx_rx(struct vchiq_instance *instance, 


		userdata = &waiter->bulk_waiter;



		status = vchiq_bulk_xfer_blocking_interruptible(instance, args->handle,

		status = vchiq_bulk_xfer_blocking(instance, args->handle,

						  NULL, args->data, args->size,

						  userdata, dir);
@@ -330,11 +330,11 @@ static int vchiq_irq_queue_bulk_tx_rx(struct vchiq_instance *instance, 
			waiter, current->pid);

		userdata = &waiter->bulk_waiter;



		status = vchiq_bulk_xfer_waiting_interruptible(instance, args->handle, userdata);

		status = vchiq_bulk_xfer_waiting(instance, args->handle, userdata);

	} else {

		userdata = args->userdata;



		status = vchiq_bulk_xfer_callback_interruptible(instance, args->handle, NULL,

		status = vchiq_bulk_xfer_callback(instance, args->handle, NULL,

						  args->data, args->size,

						  args->mode, userdata, dir);