linux-kernel - Re: [RFC PATCH v2 1/3] ufs: mcq: Add supporting functions for mcq abort

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Message-ID: <1ca7dbef-5747-29c2-a11c-086cf36d636f@acm.org>
Date:   Thu, 9 Mar 2023 10:15:23 -0800
From:   Bart Van Assche <bvanassche@....org>
To:     "Bao D. Nguyen" <quic_nguyenb@...cinc.com>,
        quic_asutoshd@...cinc.com, quic_cang@...cinc.com, mani@...nel.org,
        stanley.chu@...iatek.com, adrian.hunter@...el.com,
        beanhuo@...ron.com, avri.altman@....com, martin.petersen@...cle.com
Cc:     linux-scsi@...r.kernel.org, Alim Akhtar <alim.akhtar@...sung.com>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        Arthur Simchaev <Arthur.Simchaev@....com>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH v2 1/3] ufs: mcq: Add supporting functions for mcq
 abort

On 3/8/23 21:28, Bao D. Nguyen wrote:
> +static bool ufshcd_mcq_sqe_search(struct ufs_hba *hba,
> +		struct ufs_hw_queue *hwq, int task_tag)
> +{
> +	struct utp_transfer_req_desc *utrd;
> +	u32 mask = hwq->max_entries - 1;
> +	bool ret = false;
> +	u64 addr, match;
> +	u32 i;

The variable name "i" is usually used for a loop index. In this case it 
represents a slot in the submission queue. How about renaming "i" into 
"slot"?

> +static inline void ufshcd_mcq_update_sq_head_slot(struct ufs_hw_queue *q)
> +{
> +	u32 val = readl(q->mcq_sq_head);
> +
> +	q->sq_head_slot = val / sizeof(struct utp_transfer_req_desc);
> +}

Please modify this function such that it returns the head slot value 
instead of storing it in a member variable and remove the sq_head_slot 
member variable. Storing the sq_head_slot value in a member variable 
seems wrong to me since the value of that variable will be outdated as 
soon as the submission queue is restarted.

> +static inline bool ufshcd_mcq_is_sq_empty(struct ufs_hw_queue *q)
> +{
> +	return q->sq_head_slot == q->sq_tail_slot;
> +}

Please remove this function and inline this function into its callers.

Thanks,

Bart.