On Mon, Aug 12, 2024 at 08:17:43PM +0100, Pavel Begunkov wrote: > On 8/12/24 17:58, David Sterba wrote: > > On Mon, Aug 12, 2024 at 05:10:15PM +0100, Pavel Begunkov wrote: > >> And the last point, I'm surprised there are two versions of > >> btrfs_ioctl_encoded_io_args. Maybe, it's a good moment to fix it if > >> we're creating a new interface. > >> > >> E.g. by adding a new structure defined right with u64 and such, use it > >> in io_uring, and cast to it in the ioctl code when it's x64 (with > >> a good set of BUILD_BUG_ON sprinkled) and convert structures otherwise? > > > > If you mean the 32bit version of the ioctl struct > > (btrfs_ioctl_encoded_io_args_32), I don't think we can fix it. It's been > > Right, I meant btrfs_ioctl_encoded_io_args_32. And to clarify, nothing > can be done for the ioctl(2) part, I only suggested to have a single > structure when it comes to io_uring. > > > there from the beginning and it's not a mistake. I don't remember the > > details why and only vaguely remember that I'd asked why we need it. > > Similar 64/32 struct is in the send ioctl but that was a mistake due to > > a pointer being passed in the structure and that needs to be handled due > > to different type width. > > Would be interesting to learn why, maybe Omar remembers? Only two > fields are not explicitly sized, both could've been just u64. > The structure iov points to (struct iovec) would've had a compat > flavour, but that doesn't require a separate > btrfs_ioctl_encoded_io_args. Found it: "why don't we avoid the send 32bit workaround" https://lore.kernel.org/linux-btrfs/20190828120650.GZ2752@xxxxxxxxxxxxx/ "because big-endian" https://lore.kernel.org/linux-btrfs/20190903171458.GA7452@vader/
