[PATCH 1/2] drm/amdgpu/sdma: fix engine reset handling

[Alex Deucher]

Move the kfd suspend/resume code into the caller.  That
is where the KFD is likely to detect a reset so on the KFD
side there is no need to call them.  Also add a mutex to
lock the actual reset sequence.

v2: make the locking per instance

Fixes: bac38ca8c475 ("drm/amdkfd: implement per queue sdma reset for gfx 9.4+")
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_sdma.c          | 15 +++------------
 drivers/gpu/drm/amd/amdgpu/amdgpu_sdma.h          |  3 ++-
 drivers/gpu/drm/amd/amdgpu/sdma_v4_4_2.c          |  9 ++++++++-
 .../gpu/drm/amd/amdkfd/kfd_device_queue_manager.c |  2 +-
 4 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_sdma.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_sdma.c
index 03c4c012a1508..1b0b2598a90a7 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_sdma.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_sdma.c
@@ -524,7 +524,6 @@ void amdgpu_sdma_register_on_reset_callbacks(struct amdgpu_device *adev, struct
  * amdgpu_sdma_reset_engine - Reset a specific SDMA engine
  * @adev: Pointer to the AMDGPU device
  * @instance_id: ID of the SDMA engine instance to reset
- * @suspend_user_queues: check if suspend user queue.
  *
  * This function performs the following steps:
  * 1. Calls all registered pre_reset callbacks to allow KFD and AMDGPU to save their state.
@@ -533,7 +532,7 @@ void amdgpu_sdma_register_on_reset_callbacks(struct amdgpu_device *adev, struct
  *
  * Returns: 0 on success, or a negative error code on failure.
  */
-int amdgpu_sdma_reset_engine(struct amdgpu_device *adev, uint32_t instance_id, bool suspend_user_queues)
+int amdgpu_sdma_reset_engine(struct amdgpu_device *adev, uint32_t instance_id)
 {
 	struct sdma_on_reset_funcs *funcs;
 	int ret = 0;
@@ -542,13 +541,7 @@ int amdgpu_sdma_reset_engine(struct amdgpu_device *adev, uint32_t instance_id, b
 	struct amdgpu_ring *page_ring = &sdma_instance->page;
 	bool gfx_sched_stopped = false, page_sched_stopped = false;
 
-	/* Suspend KFD if suspend_user_queues is true.
-	 * prevent the destruction of in-flight healthy user queue packets and
-	 * avoid race conditions between KFD and KGD during the reset process.
-	 */
-	if (suspend_user_queues)
-		amdgpu_amdkfd_suspend(adev, false);
-
+	mutex_lock(&sdma_instance->engine_reset_mutex);
 	/* Stop the scheduler's work queue for the GFX and page rings if they are running.
 	* This ensures that no new tasks are submitted to the queues while
 	* the reset is in progress.
@@ -609,9 +602,7 @@ int amdgpu_sdma_reset_engine(struct amdgpu_device *adev, uint32_t instance_id, b
 			drm_sched_wqueue_start(&page_ring->sched);
 		}
 	}
-
-	if (suspend_user_queues)
-		amdgpu_amdkfd_resume(adev, false);
+	mutex_unlock(&sdma_instance->engine_reset_mutex);
 
 	return ret;
 }
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_sdma.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_sdma.h
index 9651693200655..8e7e794ff136f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_sdma.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_sdma.h
@@ -64,6 +64,7 @@ struct amdgpu_sdma_instance {
 	struct amdgpu_bo	*sdma_fw_obj;
 	uint64_t		sdma_fw_gpu_addr;
 	uint32_t		*sdma_fw_ptr;
+	struct mutex		engine_reset_mutex;
 };
 
 enum amdgpu_sdma_ras_memory_id {
@@ -169,7 +170,7 @@ struct amdgpu_buffer_funcs {
 };
 
 void amdgpu_sdma_register_on_reset_callbacks(struct amdgpu_device *adev, struct sdma_on_reset_funcs *funcs);
-int amdgpu_sdma_reset_engine(struct amdgpu_device *adev, uint32_t instance_id, bool suspend_user_queues);
+int amdgpu_sdma_reset_engine(struct amdgpu_device *adev, uint32_t instance_id);
 
 #define amdgpu_emit_copy_buffer(adev, ib, s, d, b, t) (adev)->mman.buffer_funcs->emit_copy_buffer((ib),  (s), (d), (b), (t))
 #define amdgpu_emit_fill_buffer(adev, ib, s, d, b) (adev)->mman.buffer_funcs->emit_fill_buffer((ib), (s), (d), (b))
diff --git a/drivers/gpu/drm/amd/amdgpu/sdma_v4_4_2.c b/drivers/gpu/drm/amd/amdgpu/sdma_v4_4_2.c
index fd34dc1380811..927db7a080f0a 100644
--- a/drivers/gpu/drm/amd/amdgpu/sdma_v4_4_2.c
+++ b/drivers/gpu/drm/amd/amdgpu/sdma_v4_4_2.c
@@ -1445,6 +1445,7 @@ static int sdma_v4_4_2_sw_init(struct amdgpu_ip_block *ip_block)
 	}
 
 	for (i = 0; i < adev->sdma.num_instances; i++) {
+		mutex_init(&adev->sdma.instance[i].engine_reset_mutex);
 		ring = &adev->sdma.instance[i].ring;
 		ring->ring_obj = NULL;
 		ring->use_doorbell = true;
@@ -1666,7 +1667,13 @@ static int sdma_v4_4_2_reset_queue(struct amdgpu_ring *ring, unsigned int vmid)
 {
 	struct amdgpu_device *adev = ring->adev;
 	u32 id = GET_INST(SDMA0, ring->me);
-	return amdgpu_sdma_reset_engine(adev, id, true);
+	int r;
+
+	amdgpu_amdkfd_suspend(adev, false);
+	r = amdgpu_sdma_reset_engine(adev, id);
+	amdgpu_amdkfd_resume(adev, false);
+
+	return r;
 }
 
 static int sdma_v4_4_2_stop_queue(struct amdgpu_device *adev, uint32_t instance_id)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
index 2ed003d3ff0e0..c610e172a2b83 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
@@ -2310,7 +2310,7 @@ static int reset_hung_queues_sdma(struct device_queue_manager *dqm)
 				continue;
 
 			/* Reset engine and check. */
-			if (amdgpu_sdma_reset_engine(dqm->dev->adev, i, false) ||
+			if (amdgpu_sdma_reset_engine(dqm->dev->adev, i) ||
 			    dqm->dev->kfd2kgd->hqd_sdma_get_doorbell(dqm->dev->adev, i, j) ||
 			    !set_sdma_queue_as_reset(dqm, doorbell_off)) {
 				r = -ENOTRECOVERABLE;
-- 
2.48.1