2017-12-04 17:38 GMT+08:00 Cornelia Huck <cohuck@xxxxxxxxxx>: > On Sat, 2 Dec 2017 00:55:39 +0800 > weiping zhang <zwp10758@xxxxxxxxx> wrote: > >> On Wed, Nov 29, 2017 at 10:50:44AM +0100, Cornelia Huck wrote: > >> > We hold an extra reference to the struct device, even after a failed >> > register, and it is the responsibility of the caller to give up that >> > reference once no longer needed. As callers toregister_virtio_device() >> > embed the struct virtio_device, it needs to be their responsibility. >> > Looking at the existing callers, >> > >> > - ccw does a put_device >> > - pci, mmio and remoteproc do nothing, causing a leak >> > - vop does a free on the embedding structure, which is a big no-no >> > >> > Thoughts? >> Sorry to relay late and thanks for your review. >> Do you mean the "extra reference to the struct device" caused by the >> following code? >> >> err = device_register(&dev->dev); >> device_add(dev) >> get_device(dev) >> If I'm understand right, I think there is no extra reference if we fail >> virtio_register_device, because if device_register we don't get a >> reference. > > The device_initialize() already gives you a reference. If device_add() > fails, it has cleaned up any additional reference it might have > obtained, but the initial reference is still there and needs to be > released by the caller. Thanks your clarify, I also notice the comments at device_register, device_initialize, device_add, * NOTE: _Never_ directly free @dev after calling this function, even * if it returned an error! Always use put_device() to give up the * reference initialized in this function instead. -- Thanks weiping _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
