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Commit d9ad2024 authored by Asutosh Das's avatar Asutosh Das
Browse files

scsi: ufs: error out all issued requests after shutdown 



After PON (power-off notification) is sent, no requests
should be issued to the driver.
This change errors out all requests except from shutdown
context after shutdown is initiated.

Change-Id: Id499abc27303bfed72fab4d61abb872bad7d9043
Signed-off-by: default avatarAsutosh Das <asutoshd@codeaurora.org>
parent 03d619d6

drivers/scsi/ufs/ufshcd.c

+107 −15
Original line number Diff line number Diff line
@@ -2632,6 +2632,65 @@ static inline u16 ufshcd_upiu_wlun_to_scsi_wlun(u8 upiu_wlun_id) 
	return (upiu_wlun_id & ~UFS_UPIU_WLUN_ID) | SCSI_W_LUN_BASE;

}



/**

 * ufshcd_get_write_lock - synchronize between shutdown, scaling &

 * arrival of requests

 * @hba: ufs host

 *

 * Lock is predominantly held by shutdown context thus, ensuring

 * that no requests from any other context may sneak through.

 */

static void ufshcd_get_write_lock(struct ufs_hba *hba)

{

	down_write(&hba->lock);

	hba->issuing_task = current;

}



/**

 * ufshcd_get_read_lock - synchronize between shutdown, scaling &

 * arrival of requests

 * @hba: ufs host

 *

 * Returns 1 if acquired, < 0 on contention

 *

 * After shutdown's initiated, allow requests only from shutdown

 * context. The sync between scaling & issue is maintained

 * as is and this restructuring syncs shutdown with these too.

 */

static int ufshcd_get_read_lock(struct ufs_hba *hba)

{

	int err = 0;



	err = down_read_trylock(&hba->lock);

	if (err > 0)

		goto out;

	if (hba->issuing_task == current)

		return 0;

	else if (!ufshcd_is_shutdown_ongoing(hba))

		return -EAGAIN;

	else

		return -EPERM;



out:

	hba->issuing_task = current;

	return err;

}



/**

 * ufshcd_put_read_lock - synchronize between shutdown, scaling &

 * arrival of requests

 * @hba: ufs host

 *

 * Returns none

 */

static inline void ufshcd_put_read_lock(struct ufs_hba *hba)

{

	if (!ufshcd_is_shutdown_ongoing(hba)) {

		hba->issuing_task = NULL;

		up_read(&hba->lock);

	}

}



/**

 * ufshcd_queuecommand - main entry point for SCSI requests

 * @cmd: command from SCSI Midlayer
@@ -2657,8 +2716,16 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd) 
		BUG();

	}



	if (!down_read_trylock(&hba->clk_scaling_lock))

	err = ufshcd_get_read_lock(hba);

	if (unlikely(err < 0)) {

		if (err == -EPERM) {

			set_host_byte(cmd, DID_ERROR);

			cmd->scsi_done(cmd);

			return 0;

		}

		if (err == -EAGAIN)

			return SCSI_MLQUEUE_HOST_BUSY;

	}



	spin_lock_irqsave(hba->host->host_lock, flags);
@@ -2798,7 +2865,7 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd) 
out_unlock:

	spin_unlock_irqrestore(hba->host->host_lock, flags);

out:

	up_read(&hba->clk_scaling_lock);

	ufshcd_put_read_lock(hba);

	return err;

}
@@ -2990,7 +3057,12 @@ static int ufshcd_exec_dev_cmd(struct ufs_hba *hba, 
	struct completion wait;

	unsigned long flags;



	down_read(&hba->clk_scaling_lock);

	/*

	 * May get invoked from shutdown and IOCTL contexts.

	 * In shutdown context, it comes in with lock acquired.

	 */

	if (!ufshcd_is_shutdown_ongoing(hba))

		down_read(&hba->lock);



	/*

	 * Get free slot, sleep if slots are unavailable.
@@ -3023,7 +3095,8 @@ static int ufshcd_exec_dev_cmd(struct ufs_hba *hba, 
out_put_tag:

	ufshcd_put_dev_cmd_tag(hba, tag);

	wake_up(&hba->dev_cmd.tag_wq);

	up_read(&hba->clk_scaling_lock);

	if (!ufshcd_is_shutdown_ongoing(hba))

		up_read(&hba->lock);

	return err;

}
@@ -8659,12 +8732,27 @@ int ufshcd_shutdown(struct ufs_hba *hba) 
	if (ufshcd_is_ufs_dev_poweroff(hba) && ufshcd_is_link_off(hba))

		goto out;



	if (pm_runtime_suspended(hba->dev)) {

		ret = ufshcd_runtime_resume(hba);

	pm_runtime_get_sync(hba->dev);

	ufshcd_hold_all(hba);

	/**

	 * (1) Acquire the lock to stop any more requests

	 * (2) Set state to shutting down

	 * (3) Suspend clock scaling

	 * (4) Wait for all issued requests to complete

	 */

	ufshcd_get_write_lock(hba);

	ufshcd_mark_shutdown_ongoing(hba);

	ufshcd_scsi_block_requests(hba);

	ufshcd_suspend_clkscaling(hba);

	ret = ufshcd_wait_for_doorbell_clr(hba, U64_MAX);

	if (ret)

			goto out;

	}



		dev_err(hba->dev, "%s: waiting for DB clear: failed: %d\n",

			__func__, ret);

	/* Requests may have errored out above, let it be handled */

	flush_work(&hba->eh_work);

	/* reqs issued from contexts other than shutdown will fail from now */

	ufshcd_scsi_unblock_requests(hba);

	ufshcd_release_all(hba);

	ret = ufshcd_suspend(hba, UFS_SHUTDOWN_PM);

out:

	if (ret)
@@ -8854,10 +8942,10 @@ static int ufshcd_clock_scaling_prepare(struct ufs_hba *hba) 
	 * clock scaling is in progress

	 */

	ufshcd_scsi_block_requests(hba);

	down_write(&hba->clk_scaling_lock);

	down_write(&hba->lock);

	if (ufshcd_wait_for_doorbell_clr(hba, DOORBELL_CLR_TOUT_US)) {

		ret = -EBUSY;

		up_write(&hba->clk_scaling_lock);

		up_write(&hba->lock);

		ufshcd_scsi_unblock_requests(hba);

	}
@@ -8866,7 +8954,7 @@ static int ufshcd_clock_scaling_prepare(struct ufs_hba *hba) 


static void ufshcd_clock_scaling_unprepare(struct ufs_hba *hba)

{

	up_write(&hba->clk_scaling_lock);

	up_write(&hba->lock);

	ufshcd_scsi_unblock_requests(hba);

}
@@ -9049,6 +9137,10 @@ static void ufshcd_clk_scaling_resume_work(struct work_struct *work) 
					   clk_scaling.resume_work);

	unsigned long irq_flags;



	/* Let's not resume scaling if shutdown is ongoing */

	if (ufshcd_is_shutdown_ongoing(hba))

		return;



	spin_lock_irqsave(hba->host->host_lock, irq_flags);

	if (!hba->clk_scaling.is_suspended) {

		spin_unlock_irqrestore(hba->host->host_lock, irq_flags);
@@ -9261,7 +9353,7 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq) 
	/* Initialize mutex for device management commands */

	mutex_init(&hba->dev_cmd.lock);



	init_rwsem(&hba->clk_scaling_lock);

	init_rwsem(&hba->lock);



	/* Initialize device management tag acquire wait queue */

	init_waitqueue_head(&hba->dev_cmd.tag_wq);

drivers/scsi/ufs/ufshcd.h

+14 −1
Original line number Diff line number Diff line
@@ -895,7 +895,10 @@ struct ufs_hba { 
	enum bkops_status urgent_bkops_lvl;

	bool is_urgent_bkops_lvl_checked;



	struct rw_semaphore clk_scaling_lock;

	/* sync b/w diff contexts */

	struct rw_semaphore lock;

	struct task_struct *issuing_task;

	unsigned long shutdown_in_prog;



	struct reset_control *core_reset;

	/* If set, don't gate device ref_clk during clock gating */
@@ -904,6 +907,16 @@ struct ufs_hba { 
	int scsi_block_reqs_cnt;

};



static inline void ufshcd_mark_shutdown_ongoing(struct ufs_hba *hba)

{

	set_bit(0, &hba->shutdown_in_prog);

}



static inline bool ufshcd_is_shutdown_ongoing(struct ufs_hba *hba)

{

	return !!(test_bit(0, &hba->shutdown_in_prog));

}



/* Returns true if clocks can be gated. Otherwise false */

static inline bool ufshcd_is_clkgating_allowed(struct ufs_hba *hba)

{