Re: [PATCH 10/11] scsi: ufs: Optimize the command queueing code

Bart Van Assche
2021-11-10T18:59:00Z

On 11/10/21 12:04 AM, Adrian Hunter wrote:
> On 10/11/2021 02:44, Bart Van Assche wrote:
>> @@ -2698,8 +2653,11 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
>>
>> WARN_ONCE(tag < 0, "Invalid tag %d\n", tag);
>>
>> - if (!down_read_trylock(&hba->clk_scaling_lock))
>> - return SCSI_MLQUEUE_HOST_BUSY;
>> + /*
>> + * Allows ufshcd_clock_scaling_prepare() and also the UFS error handler
>> + * to wait for prior ufshcd_queuecommand() calls.
>> + */
>> + rcu_read_lock();
>
> The improvement to flush/drain ufshcd_queuecommand() via RCU should
> be a separate patch because it is not dependent on the other changes.

I will split this patch into two patches.

Thanks,

Bart.