Re: [PATCH 1/5] io_uring: prepare for extending io_uring with bpf

[Ming Lei <ming.lei@redhat.com>]

On Tue, Dec 30, 2025 at 08:13:40PM -0500, Caleb Sander Mateos wrote:
> On Tue, Nov 4, 2025 at 8:22 AM Ming Lei <ming.lei@redhat.com> wrote:
> >
> > Add one bpf operation & related framework and prepare for extending io_uring
> > with bpf.
> >
> > Signed-off-by: Ming Lei <ming.lei@redhat.com>
> > ---
> >  include/uapi/linux/io_uring.h |  1 +
> >  init/Kconfig                  |  7 +++++++
> >  io_uring/Makefile             |  1 +
> >  io_uring/bpf.c                | 26 ++++++++++++++++++++++++++
> >  io_uring/opdef.c              | 10 ++++++++++
> >  io_uring/uring_bpf.h          | 26 ++++++++++++++++++++++++++
> >  6 files changed, 71 insertions(+)
> >  create mode 100644 io_uring/bpf.c
> >  create mode 100644 io_uring/uring_bpf.h
> >
> > diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
> > index 04797a9b76bc..b167c1d4ce6e 100644
> > --- a/include/uapi/linux/io_uring.h
> > +++ b/include/uapi/linux/io_uring.h
> > @@ -303,6 +303,7 @@ enum io_uring_op {
> >         IORING_OP_PIPE,
> >         IORING_OP_NOP128,
> >         IORING_OP_URING_CMD128,
> > +       IORING_OP_BPF,
> >
> >         /* this goes last, obviously */
> >         IORING_OP_LAST,
> > diff --git a/init/Kconfig b/init/Kconfig
> > index cab3ad28ca49..14d566516643 100644
> > --- a/init/Kconfig
> > +++ b/init/Kconfig
> > @@ -1843,6 +1843,13 @@ config IO_URING
> >           applications to submit and complete IO through submission and
> >           completion rings that are shared between the kernel and application.
> >
> > +config IO_URING_BPF
> > +       bool "Enable IO uring bpf extension" if EXPERT
> > +       depends on IO_URING && BPF
> > +       help
> > +         This option enables bpf extension for the io_uring interface, so
> > +         application can define its own io_uring operation by bpf program.
> > +
> >  config GCOV_PROFILE_URING
> >         bool "Enable GCOV profiling on the io_uring subsystem"
> >         depends on IO_URING && GCOV_KERNEL
> > diff --git a/io_uring/Makefile b/io_uring/Makefile
> > index bc4e4a3fa0a5..35eeeaf64489 100644
> > --- a/io_uring/Makefile
> > +++ b/io_uring/Makefile
> > @@ -22,3 +22,4 @@ obj-$(CONFIG_NET_RX_BUSY_POLL)        += napi.o
> >  obj-$(CONFIG_NET) += net.o cmd_net.o
> >  obj-$(CONFIG_PROC_FS) += fdinfo.o
> >  obj-$(CONFIG_IO_URING_MOCK_FILE) += mock_file.o
> > +obj-$(CONFIG_IO_URING_BPF)     += bpf.o
> > diff --git a/io_uring/bpf.c b/io_uring/bpf.c
> > new file mode 100644
> > index 000000000000..8c47df13c7b5
> > --- /dev/null
> > +++ b/io_uring/bpf.c
> > @@ -0,0 +1,26 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/* Copyright (c) 2024 Red Hat */
> > +
> > +#include <linux/kernel.h>
> > +#include <linux/errno.h>
> > +#include <uapi/linux/io_uring.h>
> > +#include "io_uring.h"
> > +#include "uring_bpf.h"
> > +
> > +int io_uring_bpf_issue(struct io_kiocb *req, unsigned int issue_flags)
> > +{
> > +       return -ECANCELED;
> > +}
> > +
> > +int io_uring_bpf_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
> > +{
> > +       return -EOPNOTSUPP;
> > +}
> > +
> > +void io_uring_bpf_fail(struct io_kiocb *req)
> > +{
> > +}
> > +
> > +void io_uring_bpf_cleanup(struct io_kiocb *req)
> > +{
> > +}
> > diff --git a/io_uring/opdef.c b/io_uring/opdef.c
> > index df52d760240e..d93ee3d577d4 100644
> > --- a/io_uring/opdef.c
> > +++ b/io_uring/opdef.c
> > @@ -38,6 +38,7 @@
> >  #include "futex.h"
> >  #include "truncate.h"
> >  #include "zcrx.h"
> > +#include "uring_bpf.h"
> >
> >  static int io_no_issue(struct io_kiocb *req, unsigned int issue_flags)
> >  {
> > @@ -593,6 +594,10 @@ const struct io_issue_def io_issue_defs[] = {
> >                 .prep                   = io_uring_cmd_prep,
> >                 .issue                  = io_uring_cmd,
> >         },
> > +       [IORING_OP_BPF] = {
> > +               .prep                   = io_uring_bpf_prep,
> > +               .issue                  = io_uring_bpf_issue,
> 
> Should this set .prep = io_eopnotsupp_prep for !CONFIG_IO_URING_BPF
> and remove the stub implementations? That would be more consistent
> with the other opcodes when they are configured out, and ensure
> io_uring_op_supported(IORING_OP_BPF) returns false for
> !CONFIG_IO_URING_BPF.

Yeah, good point!


Thanks,
Ming