On 5/11/22 6:28 PM, Al Viro wrote:
> On Wed, May 11, 2022 at 09:43:46PM +0000, Al Viro wrote:
>
>> 3) ovl_aio_put() is hard to follow (and some of the callers are poking
>> where they shouldn't), no idea if it's correct. struct fd is manually
>> constructed there, anyway.
>
> Speaking of poking in the internals:
>
> SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
> u32, min_complete, u32, flags, const void __user *, argp,
> size_t, argsz)
> {
> ...
> struct fd f;
> ...
> if (flags & IORING_ENTER_REGISTERED_RING) {
> struct io_uring_task *tctx = current->io_uring;
>
> if (!tctx || fd >= IO_RINGFD_REG_MAX)
> return -EINVAL;
> fd = array_index_nospec(fd, IO_RINGFD_REG_MAX);
> f.file = tctx->registered_rings[fd];
> if (unlikely(!f.file))
> return -EBADF;
> } else {
> f = fdget(fd);
> if (unlikely(!f.file))
> return -EBADF;
> }
> ...
> a bunch of accesses to f.file
> ...
> if (!(flags & IORING_ENTER_REGISTERED_RING))
> fdput(f);
>
> Note that f.flags is left uninitialized in the first case; it doesn't
> break since we have fdput(f) (which does look at f.flags) done only
> in the case where we don't have IORING_ENTER_REGISTERED_RING in flags
> and since flags remains unchanged since the first if. But it would
> be just as easy to set f.flags to 0 and use fdput() in both cases...
>
> Jens, do you have any objections against the following? Easier to
> follow that way...
No, I think that looks fine. If you need it for other changes:
Reviewed-by: Jens Axboe <axboe@xxxxxxxxx>
(or let me know if you want me to take it).
--
Jens Axboe
