Re: [PATCH v3 8/9] scsi: ufs: Update the fast abort path in ufshcd_abort() for PM requests

[Bart Van Assche <bvanassche@acm.org>]

On 6/12/21 12:07 AM, Can Guo wrote:
> Sigh... I also want my life and work to be easier...

How about reducing the number of states and state transitions in the UFS
driver?

One source of complexity is that ufshcd_err_handler() is scheduled
independently of the SCSI error handler and hence may run concurrently
with the SCSI error handler. Has the following already been considered?
- Call ufshcd_err_handler() synchronously from ufshcd_abort() and
ufshcd_eh_host_reset_handler() instead of asynchronously.
- Call scsi_schedule_eh() from ufshcd_uic_pwr_ctrl() and
ufshcd_check_errors() instead of ufshcd_schedule_eh_work().

These changes will guarantee that all commands have completed or timed
out before ufshcd_err_handler() is called. I think that would allow to
remove e.g. the following code from the error handler:

	ufshcd_scsi_block_requests(hba);
	/* Drain ufshcd_queuecommand() */
	down_write(&hba->clk_scaling_lock);
	up_write(&hba->clk_scaling_lock);

Thanks,

Bart.