In certain scenarios, it is possible for multiple cache flushes to be requested before the previous one completes. This patch introduces the cache_flush_lock mutex to serialize these operations and ensure that any requested cache flushes are completed instead of dropped.
Reviewed-by: Liviu Dudau <[email protected]> Co-developed-by: Dennis Tsiang <[email protected]> Signed-off-by: Dennis Tsiang <[email protected]> Signed-off-by: Karunika Choo <[email protected]> --- v2: - Added missing 'Signed-off-by' for Dennis. - Picked up R-b from Liviu. - Link to v1: https://lore.kernel.org/all/[email protected]/ drivers/gpu/drm/panthor/panthor_gpu.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/gpu/drm/panthor/panthor_gpu.c b/drivers/gpu/drm/panthor/panthor_gpu.c index cb7a335e07d7..030409371037 100644 --- a/drivers/gpu/drm/panthor/panthor_gpu.c +++ b/drivers/gpu/drm/panthor/panthor_gpu.c @@ -35,6 +35,9 @@ struct panthor_gpu { /** @reqs_acked: GPU request wait queue. */ wait_queue_head_t reqs_acked; + + /** @cache_flush_lock: Lock to serialize cache flushes */ + struct mutex cache_flush_lock; }; /** @@ -204,6 +207,7 @@ int panthor_gpu_init(struct panthor_device *ptdev) spin_lock_init(&gpu->reqs_lock); init_waitqueue_head(&gpu->reqs_acked); + mutex_init(&gpu->cache_flush_lock); ptdev->gpu = gpu; panthor_gpu_init_info(ptdev); @@ -353,6 +357,9 @@ int panthor_gpu_flush_caches(struct panthor_device *ptdev, bool timedout = false; unsigned long flags; + /* Serialize cache flush operations. */ + guard(mutex)(&ptdev->gpu->cache_flush_lock); + spin_lock_irqsave(&ptdev->gpu->reqs_lock, flags); if (!drm_WARN_ON(&ptdev->base, ptdev->gpu->pending_reqs & GPU_IRQ_CLEAN_CACHES_COMPLETED)) { -- 2.49.0
