linux-kernel - Re: [PATCH 2/2] drivers: soc: Add LLCC driver

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Date:   Fri, 23 Mar 2018 16:57:52 -0700
From:   Channa <ckadabi@...eaurora.org>
To:     Channagoud Kadabi <ckadabi@...eaurora.org>
Cc:     linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, linux-arm@...ts.infradead.org,
        linux-kernel@...r.kernel.org, tsoni@...eaurora.org,
        sboyd@...eaurora.org, kyan@...eaurora.org,
        linux-kernel-owner@...r.kernel.org
Subject: Re: [PATCH 2/2] drivers: soc: Add LLCC driver

On 2018-03-19 07:55, Jordan Crouse wrote:
> On Thu, Jan 25, 2018 at 03:55:13PM -0800, Channagoud Kadabi wrote:
>> LLCC (Last Level Cache Controller) provides additional cache memory
>> in the system. LLCC is partitioned into muliple slices and each
>> slice gets its own priority, size, ID and other config parameters.
>> LLCC driver programs these parameters for each slice. Clients that
>> are assigned to use LLCC need to get information such size & ID of the
>> slice for their usecase and activate or deactivate the slice as 
>> needed.
>> LLCC driver provides API interfaces for the clients to perform these
>> operations.
> 
> <snip>
> 
>> +/**
>> + * llcc_slice_deactivate - Deactivate the llcc slice
>> + * @desc: Pointer to llcc slice descriptor
>> + *
>> + * A value zero will be returned on success and a negative errno will
>> + * be returned in error cases
>> + */
>> +int llcc_slice_deactivate(struct llcc_slice_desc *desc)
>> +{
>> +	u32 act_ctrl_val;
>> +	int rc = -EINVAL;
>> +	struct llcc_drv_data *drv;
>> +
>> +	if (desc == NULL) {
>> +		pr_err("Input descriptor supplied is invalid\n");
> 
> Sorry that this is out of the blue, but I was reviewing a client driver 
> that
> uses this API. This should not print an error - we should be allowed to 
> safely
> pass a null pointer from an aborted sequence in the driver without the
> conditional checks and it shouldn't generate a bit of log spam as it 
> goes about
> it's business.

Thanks Jordan. I will incorporate this change in my next patchset.

> 
> Jordan

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