linux-kernel - Re: [PATCH v2 2/5] ALSA: xen-front: Read sound driver configuration from Xen store

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Message-ID: <9e875172-cbc2-7019-9971-34f88ecc8d18@suse.com>
Date:   Tue, 17 Apr 2018 13:08:07 +0200
From:   Juergen Gross <jgross@...e.com>
To:     Oleksandr Andrushchenko <andr2000@...il.com>,
        xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org,
        alsa-devel@...a-project.org, boris.ostrovsky@...cle.com,
        konrad.wilk@...cle.com, perex@...ex.cz, tiwai@...e.com
Cc:     Oleksandr Andrushchenko <oleksandr_andrushchenko@...m.com>
Subject: Re: [PATCH v2 2/5] ALSA: xen-front: Read sound driver configuration
 from Xen store

On 17/04/18 10:42, Oleksandr Andrushchenko wrote:
> On 04/16/2018 03:55 PM, Juergen Gross wrote:
>> On 16/04/18 08:24, Oleksandr Andrushchenko wrote:
>>> +        goto fail;
>>> +    }
>>> +
>>> +    if (!strncasecmp(str, XENSND_STREAM_TYPE_PLAYBACK,
>>> +             sizeof(XENSND_STREAM_TYPE_PLAYBACK))) {
>>> +        stream = &pcm_instance->streams_pb[(*cur_pb)++];
>>> +    } else if (!strncasecmp(str, XENSND_STREAM_TYPE_CAPTURE,
>>> +                  sizeof(XENSND_STREAM_TYPE_CAPTURE))) {
>>> +        stream = &pcm_instance->streams_cap[(*cur_cap)++];
>>> +    } else {
>>> +        ret = -EINVAL;
>>> +        goto fail;
>>> +    }
>> Until here this function looks very much like cfg_get_stream_type().
>> Can't they use a common sub-function?
> Not really, because cfg_get_stream_type uses kasprintf
> for strings and this one devm_kasprintf. Trying to make
> a common sub-func doesn't make sense to me

Aah, okay. Didn't spot that.

>>> +    /* start from default PCM HW configuration for the card */
>>> +    cfg_read_pcm_hw(xb_dev->nodename, NULL, &cfg->pcm_hw);
>>> +
>>> +    cfg->pcm_instances =
>>> +            devm_kcalloc(&front_info->xb_dev->dev, num_devices,
>>> +                     sizeof(struct xen_front_cfg_pcm_instance),
>>> +                     GFP_KERNEL);
>>> +    if (!cfg->pcm_instances)
>>> +        return -ENOMEM;
>>> +
>>> +    for (i = 0; i < num_devices; i++) {
>>> +        ret = cfg_device(front_info, &cfg->pcm_instances[i],
>>> +                 &cfg->pcm_hw, xb_dev->nodename, i, stream_cnt);
>>> +        if (ret < 0)
>>> +            return ret;
>> Who will free all the memory allocated until now in case of an error?
> The memory is allocated with devm_xxx functions, so it will
> be freed on device destructions automatically
>>
>> And I think when removing the device freeing the memory is missing, too.
> Same as above, the kernel will take care of it while destroying the device

Okay, thanks.


Juergen