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Commit 375e055d authored by Vikram Sharma's avatar Vikram Sharma Committed by Nirmal Abraham
Browse files

msm: camera: cdm: handle deadlock 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: 3106935
Change-Id: Ie0b8982a7e55218fc5655f8e3d08a952fd852ed7
Signed-off-by: default avatarVikram Sharma <quic_vikramsa@quicinc.com>
Signed-off-by: default avatarNirmal Abraham <quic_c_nabrah@quicinc.com>
parent be866e11

drivers/cam_cdm/cam_cdm_core_common.c

+1 −6
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright (c) 2017-2021, The Linux Foundation. All rights reserved.

 * Copyright (c) 2017-2022, The Linux Foundation. All rights reserved.

 */



#include <linux/delay.h>
@@ -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

+7 −4
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright (c) 2017-2021, The Linux Foundation. All rights reserved.

 * Copyright (c) 2017-2022, The Linux Foundation. All rights reserved.

 */



#include <linux/delay.h>
@@ -1236,8 +1236,8 @@ static void cam_hw_cdm_work(struct work_struct *work) 
			return;

		}



		mutex_lock(&core->bl_fifo[fifo_idx]

			.fifo_lock);

		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))

			atomic_dec(
@@ -1251,6 +1251,7 @@ 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;

		}
@@ -1292,6 +1293,7 @@ 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 &
@@ -1387,11 +1389,12 @@ static void cam_hw_cdm_iommu_fault_handler(struct iommu_domain *domain, 
			CAM_INFO(CAM_CDM, "CDM hw is power in off state");

		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_ERR_RATE_LIMIT(CAM_CDM, "Page fault iova addr %pK",

			(void *)iova);

		cam_cdm_notify_clients(cdm_hw, CAM_CDM_CB_STATUS_PAGEFAULT,

			(void *)iova);

		mutex_unlock(&cdm_hw->hw_mutex);

		clear_bit(CAM_CDM_ERROR_HW_STATUS, &core->cdm_status);

	} else {

		CAM_ERR(CAM_CDM, "Invalid token");