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Commit f0e61863 authored by Subhash Jadavani's avatar Subhash Jadavani Committed by David Keitel
Browse files

scsi: ufs: fix deadlock during runtime resume 



Commit e21cdd59b6fbaeaf3ab0043fc49287f554fa8696 (scsi: ufs: Change power
mode at run-time via debug-fs) has introduced bug where
pm_runtime_get_sync() might get called in UFS driver's runtime resume
callback context which will cause the deadlock as pm_runtime_get_sync()
waits for the runtime resume callback to finish.

This change fixes the above bug by moving pm_runtime_get_sync() call out
of runtime resume callback context.

Change-Id: I1efa68510eb2545fc043dfa4d8bfe6f6c36ef6a8
Signed-off-by: default avatarSubhash Jadavani <subhashj@codeaurora.org>
parent 59ba60c7

drivers/scsi/ufs/debugfs.c

+2 −0
Original line number Diff line number Diff line
@@ -693,7 +693,9 @@ static ssize_t ufsdbg_power_mode_write(struct file *file, 
		__func__, pwr_mode.gear_rx, pwr_mode.gear_tx, pwr_mode.lane_rx,

		pwr_mode.lane_tx, pwr_mode.pwr_rx, pwr_mode.pwr_tx);



	pm_runtime_get_sync(hba->dev);

	ret = ufshcd_config_pwr_mode(hba, &pwr_mode);

	pm_runtime_put_sync(hba->dev);

	if (ret == -EBUSY)

		dev_err(hba->dev,

			"%s: ufshcd_config_pwr_mode failed: system is busy, try again\n",

drivers/scsi/ufs/ufshcd.c

+0 −4
Original line number Diff line number Diff line
@@ -1260,7 +1260,6 @@ ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd) 
	unsigned long flags;



	ufshcd_hold(hba, false);

	pm_runtime_get_sync(hba->dev);

	mutex_lock(&hba->uic_cmd_mutex);

	ufshcd_add_delay_before_dme_cmd(hba);
@@ -1271,7 +1270,6 @@ ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd) 
		ret = ufshcd_wait_for_uic_cmd(hba, uic_cmd);



	mutex_unlock(&hba->uic_cmd_mutex);

	pm_runtime_put_sync(hba->dev);

	ufshcd_release(hba);

	return ret;

}
@@ -2717,7 +2715,6 @@ static int ufshcd_uic_pwr_ctrl(struct ufs_hba *hba, struct uic_command *cmd) 
	int retries = POWER_MODE_RETRIES;



	ufshcd_hold(hba, false);

	pm_runtime_get_sync(hba->dev);

	mutex_lock(&hba->uic_cmd_mutex);

	init_completion(&uic_async_done);

	ufshcd_add_delay_before_dme_cmd(hba);
@@ -2787,7 +2784,6 @@ out: 
	hba->uic_async_done = NULL;

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

	mutex_unlock(&hba->uic_cmd_mutex);

	pm_runtime_put_sync(hba->dev);

	ufshcd_release(hba);

	return ret;

}