Hi Ryan
On Mon, Aug 13, 2012 at 2:00 AM, Ryan Mallon <rmallon@xxxxxxxxx> wrote:
> On 13/08/12 00:53, David Herrmann wrote:
>> /*
>> + * fblog_open/close()
>> + * These functions manage access to the underlying framebuffer. While opened, we
>> + * have a valid reference to the fb and can use it for drawing operations. When
>> + * the fb is unregistered, we drop our reference and close the fb so it can get
>> + * deleted properly. We also mark it as dead so no further fblog_open() call
>> + * will succeed.
>> + * Both functions must be called with the fb->info->lock mutex held! But make
>> + * sure to lock it _before_ locking the fblog-registration-lock. Otherwise, we
>> + * will dead-lock with fb-registration.
>> + */
>> +
>> +static int fblog_open(struct fblog_fb *fb)
>> +{
>> + int ret;
>> +
>> + mutex_lock(&fb->lock);
>> +
>> + if (test_bit(FBLOG_KILLED, &fb->flags)) {
>> + ret = -ENODEV;
>> + goto unlock;
>> + }
>> +
>> + if (test_bit(FBLOG_OPEN, &fb->flags)) {
>> + ret = 0;
>> + goto unlock;
>> + }
>> +
>> + if (!try_module_get(fb->info->fbops->owner)) {
>> + ret = -ENODEV;
>> + goto out_killed;
>> + }
>> +
>> + if (fb->info->fbops->fb_open && fb->info->fbops->fb_open(fb->info, 0)) {
>
> Should propagate the error here:
>
> if (fb->info->fbops->fb_open) {
> ret = fb->info->fbops->fb_open(fb->info, 0);
> if (ret)
> gotou out_unref;
> }
Nice catch, thanks.
>> +/*
>> * fblog framebuffer list
>> * The fblog_fbs[] array contains all currently registered framebuffers. If a
>> * framebuffer is in that list, we always must make sure that we own a reference
>> @@ -77,6 +147,7 @@ static void fblog_do_unregister(struct fb_info *info)
>>
>> fblog_fbs[info->node] = NULL;
>>
>> + fblog_close(fb, true);
>> device_del(&fb->dev);
>> put_device(&fb->dev);
>
> device_unregister?
Heh, you already mentioned this in the previous patch. I definitely
need to fix that.
>> }
>> @@ -99,6 +170,7 @@ static void fblog_do_register(struct fb_info *info, bool force)
>> return;
>>
>> fb->info = info;
>> + mutex_init(&fb->lock);
>> __module_get(THIS_MODULE);
>> device_initialize(&fb->dev);
>> fb->dev.class = fb_class;
>> @@ -113,6 +185,8 @@ static void fblog_do_register(struct fb_info *info, bool force)
>> put_device(&fb->dev);
>> return;
>> }
>> +
>> + fblog_open(fb);
>> }
>
> This function should really return an errno value.
I never used the return value in my code but as mentioned in the
previous patches, fblog_scan() should check them. So yes, I will add
this.
Thanks!
David
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