On Wed, 14 Dec 2016, David Laight wrote: > If the kernel is doing ANY validation on the frames it must copy the > data to memory the application cannot modify before doing the validation. > Otherwise the application could change the data afterwards. The application is not allowed to change the data after a work request has been submitted to send the frame. Changes are possible after the completion request has been received. The kernel can enforce that by making the frame(s) readonly and thus getting a page fault if the app would do such a thing. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>