Re: [PATCH 6/8] scsi: ufs: Make ufshcd_poll() complain about unsupported arguments

[Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>]

On Mon, Jun 17, 2024 at 02:07:45PM -0700, Bart Van Assche wrote:
> The ufshcd_poll() implementation does not support queue_num ==
> UFSHCD_POLL_FROM_INTERRUPT_CONTEXT in MCQ mode. Hence complain
> if queue_num == UFSHCD_POLL_FROM_INTERRUPT_CONTEXT in MCQ mode.
> 
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>
> ---
>  drivers/ufs/core/ufshcd.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
> index 7761ccca2115..db374a788140 100644
> --- a/drivers/ufs/core/ufshcd.c
> +++ b/drivers/ufs/core/ufshcd.c
> @@ -5562,6 +5562,7 @@ static int ufshcd_poll(struct Scsi_Host *shost, unsigned int queue_num)
>  	struct ufs_hw_queue *hwq;
>  
>  	if (is_mcq_enabled(hba)) {
> +		WARN_ON_ONCE(queue_num == UFSHCD_POLL_FROM_INTERRUPT_CONTEXT);

So what does the user has to do if this WARN_ON gets triggered? Can't we use
dev_err()/dev_warn() and return instead if the intention is to just report the
error or warning.

I know that UFS code has WARN_ON sprinkled all over, but those should be audited
at some point and also the new additions.

Also, this is a bug fix as it essentially fixes array out of the bounds issue.
So should have a fixes tag and CC stable list for backporting.

- Mani

>  		hwq = &hba->uhq[queue_num];
>  
>  		return ufshcd_mcq_poll_cqe_lock(hba, hwq);

-- 
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