Re: [PATCH v4 05/16] ufs: core: mcq: Add Multi Circular Queue support

[Bart Van Assche]

On 11/9/22 11:41, Asutosh Das wrote:
> +static int ufshcd_mcq_config_nr_queues(struct ufs_hba *hba)
> +{
> +	int i;
> +	u32 hba_maxq, rem, tot_queues;
> +	struct Scsi_Host *host = hba->host;
> +
> +	hba_maxq = FIELD_GET(GENMASK(7, 0), hba->mcq_capabilities);
> +
> +	if (!rw_queues)
> +		rw_queues = num_possible_cpus();
> +
> +	tot_queues = UFS_MCQ_NUM_DEV_CMD_QUEUES + read_queues + poll_queues +
> +			rw_queues;
> +
> +	if (hba_maxq < tot_queues) {
> +		dev_err(hba->dev, "Total queues (%d) exceeds HC capacity (%d)\n",
> +			tot_queues, hba_maxq);
> +		return -EOPNOTSUPP;
> +	}

This function can fail with default kernel module parameters, e.g. 
num_possible_cpus() == 8 and hba_maxq == 4. This is not acceptable. A 
better solution is required, e.g. reducing rw_queues if the user has not 
set this kernel module parameter.

Thanks,

Bart.