Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx> writes:
> On 27/07/2022 11:31, Kalle Valo wrote:
>> Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx> writes:
>
>>> +static ssize_t read_file_firmware_feature_caps(struct file *file,
>>> + char __user *user_buf,
>>> + size_t count, loff_t *ppos)
>>> +{
>>> + struct wcn36xx *wcn = file->private_data;
>>> + unsigned long page = get_zeroed_page(GFP_KERNEL);
>>> + char *p = (char *)page;
>>> + int i;
>>> + int ret;
>>> +
>>> + if (!p)
>>> + return -ENOMEM;
>>> +
>>> + mutex_lock(&wcn->hal_mutex);
>>> + for (i = 0; i < MAX_FEATURE_SUPPORTED; i++) {
>>> + if (wcn36xx_firmware_get_feat_caps(wcn->fw_feat_caps, i)) {
>>> + p += sprintf(p, "%s\n",
>>> + wcn36xx_firmware_get_cap_name(i));
>>> + }
>>> + }
>>> + mutex_unlock(&wcn->hal_mutex);
>>> +
>>> + ret = simple_read_from_buffer(user_buf, count, ppos, (char *)page,
>>> + (unsigned long)p - page);
>>> +
>>> + free_page(page);
>>> + return ret;
>>> +}
>>
>> Why not use the normal use kzalloc() and kfree()? That way you would not
>> need a separate page variable. What's the benefit from
>> get_zeroed_page()?
>
>
> TBH I did a copy/paste here from another driver... I forget which
>>
>> Also I don't see any checks for a memory allocation failure.
>>
>
> its there
>
> char *p = (char*) page;
>
> if (!p)
> return -ENOMEM;
Ah, it's pretty evil to have the error handling so far away from the
actual call :)
> I can V2 this for kzalloc and kfree if you prefer though
Yes, please do that. We should use standard infrastructure as much as
possible.
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