Re: [PATCH v1 1/5] bus: mhi: core: Remove the system error worker thread

[Manivannan Sadhasivam]

On Mon, May 11, 2020 at 07:03:05PM -0700, Hemant Kumar wrote:
> Remove the system error worker thread and instead have the
> execution environment worker handle that transition to serialize
> processing and avoid any possible race conditions during
> shutdown.
> 
> Signed-off-by: Hemant Kumar <hemantk@xxxxxxxxxxxxxx>
> Reviewed-by: Jeffrey Hugo <jhugo@xxxxxxxxxxxxxx>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>

Thanks,
Mani

> ---
>  drivers/bus/mhi/core/init.c     |  2 +-
>  drivers/bus/mhi/core/internal.h |  3 ++-
>  drivers/bus/mhi/core/main.c     |  6 +++---
>  drivers/bus/mhi/core/pm.c       | 32 ++++++++++++++------------------
>  include/linux/mhi.h             |  2 --
>  5 files changed, 20 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
> index 6882206..3a853c5 100644
> --- a/drivers/bus/mhi/core/init.c
> +++ b/drivers/bus/mhi/core/init.c
> @@ -34,6 +34,7 @@
>  	[DEV_ST_TRANSITION_READY] = "READY",
>  	[DEV_ST_TRANSITION_SBL] = "SBL",
>  	[DEV_ST_TRANSITION_MISSION_MODE] = "MISSION_MODE",
> +	[DEV_ST_TRANSITION_SYS_ERR] = "SYS_ERR",
>  };
>  
>  const char * const mhi_state_str[MHI_STATE_MAX] = {
> @@ -834,7 +835,6 @@ int mhi_register_controller(struct mhi_controller *mhi_cntrl,
>  	spin_lock_init(&mhi_cntrl->transition_lock);
>  	spin_lock_init(&mhi_cntrl->wlock);
>  	INIT_WORK(&mhi_cntrl->st_worker, mhi_pm_st_worker);
> -	INIT_WORK(&mhi_cntrl->syserr_worker, mhi_pm_sys_err_worker);
>  	init_waitqueue_head(&mhi_cntrl->state_event);
>  
>  	mhi_cmd = mhi_cntrl->mhi_cmd;
> diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
> index 80b32c2..f01283b 100644
> --- a/drivers/bus/mhi/core/internal.h
> +++ b/drivers/bus/mhi/core/internal.h
> @@ -386,6 +386,7 @@ enum dev_st_transition {
>  	DEV_ST_TRANSITION_READY,
>  	DEV_ST_TRANSITION_SBL,
>  	DEV_ST_TRANSITION_MISSION_MODE,
> +	DEV_ST_TRANSITION_SYS_ERR,
>  	DEV_ST_TRANSITION_MAX,
>  };
>  
> @@ -587,7 +588,7 @@ enum mhi_pm_state __must_check mhi_tryset_pm_state(
>  int mhi_queue_state_transition(struct mhi_controller *mhi_cntrl,
>  			       enum dev_st_transition state);
>  void mhi_pm_st_worker(struct work_struct *work);
> -void mhi_pm_sys_err_worker(struct work_struct *work);
> +void mhi_pm_sys_err_handler(struct mhi_controller *mhi_cntrl);
>  void mhi_fw_load_worker(struct work_struct *work);
>  int mhi_ready_state_transition(struct mhi_controller *mhi_cntrl);
>  void mhi_ctrl_ev_task(unsigned long data);
> diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
> index 6a80666..9ec9b36 100644
> --- a/drivers/bus/mhi/core/main.c
> +++ b/drivers/bus/mhi/core/main.c
> @@ -406,7 +406,7 @@ irqreturn_t mhi_intvec_threaded_handler(int irq_number, void *dev)
>  		if (MHI_IN_PBL(ee))
>  			mhi_cntrl->status_cb(mhi_cntrl, MHI_CB_FATAL_ERROR);
>  		else
> -			schedule_work(&mhi_cntrl->syserr_worker);
> +			mhi_pm_sys_err_handler(mhi_cntrl);
>  	}
>  
>  exit_intvec:
> @@ -734,7 +734,7 @@ int mhi_process_ctrl_ev_ring(struct mhi_controller *mhi_cntrl,
>  							MHI_PM_SYS_ERR_DETECT);
>  				write_unlock_irq(&mhi_cntrl->pm_lock);
>  				if (new_state == MHI_PM_SYS_ERR_DETECT)
> -					schedule_work(&mhi_cntrl->syserr_worker);
> +					mhi_pm_sys_err_handler(mhi_cntrl);
>  				break;
>  			}
>  			default:
> @@ -920,7 +920,7 @@ void mhi_ctrl_ev_task(unsigned long data)
>  		}
>  		write_unlock_irq(&mhi_cntrl->pm_lock);
>  		if (pm_state == MHI_PM_SYS_ERR_DETECT)
> -			schedule_work(&mhi_cntrl->syserr_worker);
> +			mhi_pm_sys_err_handler(mhi_cntrl);
>  	}
>  }
>  
> diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
> index 3cc238a..d9964d4 100644
> --- a/drivers/bus/mhi/core/pm.c
> +++ b/drivers/bus/mhi/core/pm.c
> @@ -449,19 +449,8 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl,
>  		to_mhi_pm_state_str(transition_state));
>  
>  	/* We must notify MHI control driver so it can clean up first */
> -	if (transition_state == MHI_PM_SYS_ERR_PROCESS) {
> -		/*
> -		 * If controller supports RDDM, we do not process
> -		 * SYS error state, instead we will jump directly
> -		 * to RDDM state
> -		 */
> -		if (mhi_cntrl->rddm_image) {
> -			dev_dbg(dev,
> -				 "Controller supports RDDM, so skip SYS_ERR\n");
> -			return;
> -		}
> +	if (transition_state == MHI_PM_SYS_ERR_PROCESS)
>  		mhi_cntrl->status_cb(mhi_cntrl, MHI_CB_SYS_ERROR);
> -	}
>  
>  	mutex_lock(&mhi_cntrl->pm_mutex);
>  	write_lock_irq(&mhi_cntrl->pm_lock);
> @@ -527,7 +516,6 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl,
>  	mutex_unlock(&mhi_cntrl->pm_mutex);
>  	dev_dbg(dev, "Waiting for all pending threads to complete\n");
>  	wake_up_all(&mhi_cntrl->state_event);
> -	flush_work(&mhi_cntrl->st_worker);
>  
>  	dev_dbg(dev, "Reset all active channels and remove MHI devices\n");
>  	device_for_each_child(mhi_cntrl->cntrl_dev, NULL, mhi_destroy_device);
> @@ -607,13 +595,17 @@ int mhi_queue_state_transition(struct mhi_controller *mhi_cntrl,
>  }
>  
>  /* SYS_ERR worker */
> -void mhi_pm_sys_err_worker(struct work_struct *work)
> +void mhi_pm_sys_err_handler(struct mhi_controller *mhi_cntrl)
>  {
> -	struct mhi_controller *mhi_cntrl = container_of(work,
> -							struct mhi_controller,
> -							syserr_worker);
> +	struct device *dev = &mhi_cntrl->mhi_dev->dev;
> +
> +	/* skip if controller supports RDDM */
> +	if (mhi_cntrl->rddm_image) {
> +		dev_dbg(dev, "Controller supports RDDM, skip SYS_ERROR\n");
> +		return;
> +	}
>  
> -	mhi_pm_disable_transition(mhi_cntrl, MHI_PM_SYS_ERR_PROCESS);
> +	mhi_queue_state_transition(mhi_cntrl, DEV_ST_TRANSITION_SYS_ERR);
>  }
>  
>  /* Device State Transition worker */
> @@ -661,6 +653,10 @@ void mhi_pm_st_worker(struct work_struct *work)
>  		case DEV_ST_TRANSITION_READY:
>  			mhi_ready_state_transition(mhi_cntrl);
>  			break;
> +		case DEV_ST_TRANSITION_SYS_ERR:
> +			mhi_pm_disable_transition
> +				(mhi_cntrl, MHI_PM_SYS_ERR_PROCESS);
> +			break;
>  		default:
>  			break;
>  		}
> diff --git a/include/linux/mhi.h b/include/linux/mhi.h
> index 2b20b9c..b008914 100644
> --- a/include/linux/mhi.h
> +++ b/include/linux/mhi.h
> @@ -331,7 +331,6 @@ struct mhi_controller_config {
>   * @wlock: Lock for protecting device wakeup
>   * @mhi_link_info: Device bandwidth info
>   * @st_worker: State transition worker
> - * @syserr_worker: System error worker
>   * @state_event: State change event
>   * @status_cb: CB function to notify power states of the device (required)
>   * @wake_get: CB function to assert device wake (optional)
> @@ -411,7 +410,6 @@ struct mhi_controller {
>  	spinlock_t wlock;
>  	struct mhi_link_info mhi_link_info;
>  	struct work_struct st_worker;
> -	struct work_struct syserr_worker;
>  	wait_queue_head_t state_event;
>  
>  	void (*status_cb)(struct mhi_controller *mhi_cntrl,
> -- 
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> a Linux Foundation Collaborative Project