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Commit 7f25abfd authored by Vikram Sharma's avatar Vikram Sharma Committed by Gerrit - the friendly Code Review server
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msm: camera: cdm: handle dead lock scenario 



This change handles a race condition in which cdm workqueue is
scheduled on one of the cores and cdm flush is executing on
another core. We come across a dead lock between fifo_lock and
hw_mutex lock.

CRs-Fixed: 3049531
Change-Id: Ie0b8982a7e55218fc5655f8e3d08a952fd852ed7
Signed-off-by: default avatarVikram Sharma <vikramsa@codeaurora.org>
parent 981b2405

drivers/cam_cdm/cam_cdm_core_common.c

+0 −5
Original line number Diff line number Diff line
@@ -180,12 +180,10 @@ void cam_cdm_notify_clients(struct cam_hw_info *cdm_hw, 
			(struct cam_cdm_bl_cb_request_entry *)data;



		client_idx = CAM_CDM_GET_CLIENT_IDX(node->client_hdl);

		mutex_lock(&cdm_hw->hw_mutex);

		client = core->clients[client_idx];

		if ((!client) || (client->handle != node->client_hdl)) {

			CAM_ERR(CAM_CDM, "Invalid client %pK hdl=%x", client,

				node->client_hdl);

			mutex_unlock(&cdm_hw->hw_mutex);

			return;

		}

		cam_cdm_get_client_refcount(client);
@@ -204,7 +202,6 @@ void cam_cdm_notify_clients(struct cam_hw_info *cdm_hw, 
		}

		mutex_unlock(&client->lock);

		cam_cdm_put_client_refcount(client);

		mutex_unlock(&cdm_hw->hw_mutex);

		return;

	} else if (status == CAM_CDM_CB_STATUS_HW_RESET_DONE ||

			status == CAM_CDM_CB_STATUS_HW_FLUSH ||
@@ -242,7 +239,6 @@ void cam_cdm_notify_clients(struct cam_hw_info *cdm_hw, 


	for (i = 0; i < CAM_PER_CDM_MAX_REGISTERED_CLIENTS; i++) {

		if (core->clients[i] != NULL) {

			mutex_lock(&cdm_hw->hw_mutex);

			client = core->clients[i];

			cam_cdm_get_client_refcount(client);

			mutex_lock(&client->lock);
@@ -265,7 +261,6 @@ void cam_cdm_notify_clients(struct cam_hw_info *cdm_hw, 
			}

			mutex_unlock(&client->lock);

			cam_cdm_put_client_refcount(client);

			mutex_unlock(&cdm_hw->hw_mutex);

		}

	}

}

drivers/cam_cdm/cam_cdm_hw_core.c

+6 −1
Original line number Diff line number Diff line
@@ -1238,6 +1238,7 @@ static void cam_hw_cdm_work(struct work_struct *work) 
			return;

		}



		mutex_lock(&cdm_hw->hw_mutex);

		mutex_lock(&core->bl_fifo[fifo_idx].fifo_lock);



		if (atomic_read(&core->bl_fifo[fifo_idx].work_record))
@@ -1251,6 +1252,7 @@ static void cam_hw_cdm_work(struct work_struct *work) 
				core->arbitration);

			mutex_unlock(&core->bl_fifo[fifo_idx]

					.fifo_lock);

			mutex_unlock(&cdm_hw->hw_mutex);

			return;

		}
@@ -1289,6 +1291,7 @@ static void cam_hw_cdm_work(struct work_struct *work) 
		}

		mutex_unlock(&core->bl_fifo[payload->fifo_idx]

			.fifo_lock);

		mutex_unlock(&cdm_hw->hw_mutex);

	}



	if (payload->irq_status &
@@ -1405,9 +1408,9 @@ static void cam_hw_cdm_iommu_fault_handler(struct cam_smmu_pf_info *pf_info) 
				cdm_hw->soc_info.index);

		for (i = 0; i < core->offsets->reg_data->num_bl_fifo; i++)

			mutex_unlock(&core->bl_fifo[i].fifo_lock);

		mutex_unlock(&cdm_hw->hw_mutex);

		cam_cdm_notify_clients(cdm_hw, CAM_CDM_CB_STATUS_PAGEFAULT,

			(void *)pf_info->iova);

		mutex_unlock(&cdm_hw->hw_mutex);

		clear_bit(CAM_CDM_ERROR_HW_STATUS, &core->cdm_status);

	} else {

		CAM_ERR(CAM_CDM, "Invalid token");
@@ -1806,9 +1809,11 @@ int cam_hw_cdm_handle_error_info( 


	if (node != NULL) {

		if (node->request_type == CAM_HW_CDM_BL_CB_CLIENT) {

			mutex_lock(&cdm_hw->hw_mutex);

			cam_cdm_notify_clients(cdm_hw,

					CAM_CDM_CB_STATUS_HW_ERROR,

					(void *)node);

			mutex_unlock(&cdm_hw->hw_mutex);

		} else if (node->request_type == CAM_HW_CDM_BL_CB_INTERNAL) {

			CAM_ERR(CAM_CDM, "Invalid node=%pK %d", node,

					node->request_type);