On Thu, Feb 18, 2021 at 02:56:06PM -0700, Alex Williamson wrote: > Looks pretty slick. I won't claim it's fully gelled in my head yet, > but AIUI you're creating these inodes on your new pseudo fs and > associating it via the actual user fd via the f_mapping pointer, which > allows multiple fds to associate and address space back to this inode > when you want to call unmap_mapping_range(). Yes, from what I can tell all the fs/inode stuff is just mandatory overhead to get a unique address_space pointer, as that is the only thing this is actually using. I have to check the mmap flow more carefully, I recall pointing to a existing race here with Daniel, but the general idea should hold. > That clarifies from the previous email how we'd store the inode on > the vfio_device without introducing yet another tracking list for > device fds. Right, you can tell from the vma what inode it is for, and the inode can tell you if it is a VFIO VMA or not, so no tracking lists needed at all. Jason
