Hi folks, Here's the second version of the media reference patchset I've been working on for some time. The lifetime of the media device (and media devnode) is now bound to that of struct device embedded in it and its memory is only released once the last reference is gone: unregistering is simply unregistering, it no longer should release memory which could be further accessed. A video node or a sub-device node also gets a reference to the media device, i.e. the release function of the video device node will release its reference to the media device. The same goes for file handles to the media device. As a side effect of this is that the media device, it is allocate together with the media devnode. The driver may also rely its own resources to the media device. Alternatively there's also a priv field to hold drivers private pointer (for container_of() is an option in this case). We could drop one of these options but currently both are possible. I've tested this by manually unbinding the omap3isp platform device while streaming. Driver changes are required for this to work; by not using dynamic allocation (i.e. media_device_alloc()) the old behaviour is still supported. This is still unlikely to be a grave problem as there are not that many device drivers that support physically removable devices. We've had this problem for other devices for many years without paying much notice --- that doesn't mean I don't think at least drivers for removable devices shouldn't be changed as part of the set later on, I'd just like to get review comments on the approach first. The three patches that originally partially resolved some of these issues are reverted in the beginning of the set. I'm still posting this as an RFC mainly since the testing is somewhat limited so far. changes since v1: - Drop kref in struct media_devnode, rely on struct device instead - Do not add a separate struct holding the cdev. It remains in struct media_devnode instead. v1 is available here: <URL:http://www.spinics.net/lists/linux-media/msg102713.html> -- Kind regards, Sakari -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
