[Spice-devel] [PATCH v5 01/13] Usbredir channel: Introduce mutex for USB redirection

[Dmitry Fleytman]

> On 9 Feb 2016, at 17:14 PM, Jonathon Jongsma <jjongsma at redhat.com> wrote:
> 
> On Thu, 2015-10-29 at 17:26 +0200, Dmitry Fleytman wrote:
>> From: Kirill Moizik <kmoizik at redhat.com>
>> 
>> This commit introduces channel mutex to allow usage of
>> channel objects in mutithreaded environments.
>> 
>> This mutex will be used to protect non thread safe
>> usbredir functions and data structures.
>> 
>> Signed-off-by: Kirill Moizik <kmoizik at redhat.com>
>> Signed-off-by: Dmitry Fleytman <dfleytma at redhat.com>
>> ---
>> src/channel-usbredir-priv.h |  4 ++++
>> src/channel-usbredir.c      | 19 +++++++++++++++++++
>> 2 files changed, 23 insertions(+)
>> 
>> diff --git a/src/channel-usbredir-priv.h b/src/channel-usbredir-priv.h
>> index 2c4c6f7..c987474 100644
>> --- a/src/channel-usbredir-priv.h
>> +++ b/src/channel-usbredir-priv.h
>> @@ -51,6 +51,10 @@ void
>> spice_usbredir_channel_disconnect_device(SpiceUsbredirChannel *channel);
>> 
>> libusb_device *spice_usbredir_channel_get_device(SpiceUsbredirChannel
>> *channel);
>> 
>> +void spice_usbredir_channel_lock(SpiceUsbredirChannel *channel);
>> +
>> +void spice_usbredir_channel_unlock(SpiceUsbredirChannel *channel);
>> +
>> void spice_usbredir_channel_get_guest_filter(
>>                           SpiceUsbredirChannel               *channel,
>>                           const struct usbredirfilter_rule  **rules_ret,
>> diff --git a/src/channel-usbredir.c b/src/channel-usbredir.c
>> index c236ee7..8cf3387 100644
>> --- a/src/channel-usbredir.c
>> +++ b/src/channel-usbredir.c
>> @@ -79,6 +79,7 @@ struct _SpiceUsbredirChannelPrivate {
>>     GSimpleAsyncResult *result;
>>     SpiceUsbAclHelper *acl_helper;
>> #endif
>> +    GMutex *flows_mutex;
>> };
>> 
>> static void channel_set_handlers(SpiceChannelClass *klass);
>> @@ -107,6 +108,8 @@ static void
>> spice_usbredir_channel_init(SpiceUsbredirChannel *channel)
>> {
>> #ifdef USE_USBREDIR
>>     channel->priv = SPICE_USBREDIR_CHANNEL_GET_PRIVATE(channel);
>> +    channel->priv->flows_mutex = g_new0(GMutex, 1);
>> +    g_mutex_init(channel->priv->flows_mutex);
>> #endif
>> }
>> 
>> @@ -182,6 +185,10 @@ static void spice_usbredir_channel_finalize(GObject *obj)
>> 
>>     if (channel->priv->host)
>>         usbredirhost_close(channel->priv->host);
>> +#ifdef USE_USBREDIR
>> +    g_mutex_clear(channel->priv->flows_mutex);
>> +    g_free(channel->priv->flows_mutex);
>> +#endif
>> 
>>     /* Chain up to the parent class */
>>     if (G_OBJECT_CLASS(spice_usbredir_channel_parent_class)->finalize)
>> @@ -561,6 +568,18 @@ static void *usbredir_alloc_lock(void) {
>> #endif
>> }
>> 
>> +void spice_usbredir_channel_lock(SpiceUsbredirChannel *channel)
>> +{
>> +    g_return_if_fail(SPICE_IS_USBREDIR_CHANNEL(channel));
>> +    g_mutex_lock(channel->priv->flows_mutex);
>> +}
>> +
>> +void spice_usbredir_channel_unlock(SpiceUsbredirChannel *channel)
>> +{
>> +  g_return_if_fail(SPICE_IS_USBREDIR_CHANNEL(channel));
>> +  g_mutex_unlock(channel->priv->flows_mutex);
>> +}
>> +
>> static void usbredir_lock_lock(void *user_data) {
>>     GMutex *mutex = user_data;
>> 
> 
> 
> 
> The code itself looks fine, but again, it's hard to judge the design or
> necessity of the mutex without seeing how it's used. I'll come back to this
> after I've reviewed the rest of the patches. Also, why did you choose the name
> "flows_mutex"?  The term "flow" is not used elsewhere in this file as far as I
> can tell.

Indeed the name may be better. Renaming device_connect_mutex.


> 
> Reviewed-by: Jonathon Jongsma <jjongsma at redhat.com>