On 8/31/21 1:52 PM, Pavel Begunkov wrote: > Add a few lines describing openat/openat2/accept bypassing normal file > tables and installing files right into the fixed file table. > > Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx> > --- > man/io_uring_enter.2 | 36 ++++++++++++++++++++++++++++++++++++ > 1 file changed, 36 insertions(+) > > diff --git a/man/io_uring_enter.2 b/man/io_uring_enter.2 > index 9ccedef..52a5e13 100644 > --- a/man/io_uring_enter.2 > +++ b/man/io_uring_enter.2 > @@ -511,6 +511,18 @@ field. See also > .BR accept4(2) > for the general description of the related system call. Available since 5.5. > > +If the > +.I file_index > +field is set to a non-negative number, the file won't be installed into the > +normal file table as usual but will be placed into the fixed file table at index > +.I file_index - 1. > +In this case, instead of returning a file descriptor, the result will contain > +0 on success or an error. If there is already a file registered at this index, I don't think non-negative is correct, it has to be set to a positive number. non-negative would include 0, which isn't correct. Should also include a note on if these types of file are used, they won't work in anything but io_uring. That's obvious to us, but should be noted that they then only live within the realm of the ring itself, not the system as a whole. -- Jens Axboe
