Commit 6df9d086 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'for-6.15/io_uring-epoll-wait-20250325' of git://git.kernel.dk/linux 

Pull io_uring epoll support from Jens Axboe:
 "This adds support for reading epoll events via io_uring.

  While this may seem counter-intuitive (and/or productive), the
  reasoning here is that quite a few existing epoll event loops can
  easily do a partial conversion to a completion based model, but are
  still stuck with one (or few) event types that remain readiness based.

  For that case, they then need to add the io_uring fd to the epoll
  context, and continue to rely on epoll_wait(2) for waiting on events.
  This misses out on the finer grained waiting that io_uring can do, to
  reduce context switches and wait for multiple events in one batch
  reliably.

  With adding support for reaping epoll events via io_uring, the whole
  legacy readiness based event types can still be reaped via epoll, with
  the overall waiting in the loop be driven by io_uring"

* tag 'for-6.15/io_uring-epoll-wait-20250325' of git://git.kernel.dk/linux:
  io_uring/epoll: add support for IORING_OP_EPOLL_WAIT
  io_uring/epoll: remove CONFIG_EPOLL guards
parents ca0b04ba 19f7e942

include/uapi/linux/io_uring.h

+1 −0
Original line number Diff line number Diff line
@@ -280,6 +280,7 @@ enum io_uring_op { 
	IORING_OP_BIND,

	IORING_OP_LISTEN,

	IORING_OP_RECV_ZC,

	IORING_OP_EPOLL_WAIT,



	/* this goes last, obviously */

	IORING_OP_LAST,

io_uring/Makefile

+5 −4
Original line number Diff line number Diff line
@@ -11,10 +11,11 @@ obj-$(CONFIG_IO_URING) += io_uring.o opdef.o kbuf.o rsrc.o notif.o \ 
					eventfd.o uring_cmd.o openclose.o \

					sqpoll.o xattr.o nop.o fs.o splice.o \

					sync.o msg_ring.o advise.o openclose.o \

					epoll.o statx.o timeout.o fdinfo.o \

					cancel.o waitid.o register.o \

					truncate.o memmap.o alloc_cache.o

					statx.o timeout.o fdinfo.o cancel.o \

					waitid.o register.o truncate.o \

					memmap.o alloc_cache.o

obj-$(CONFIG_IO_URING_ZCRX)	+= zcrx.o

obj-$(CONFIG_IO_WQ)		+= io-wq.o

obj-$(CONFIG_FUTEX)		+= futex.o

obj-$(CONFIG_EPOLL)		+= epoll.o

obj-$(CONFIG_NET_RX_BUSY_POLL)	+= napi.o

io_uring/epoll.c

+33 −2
Original line number Diff line number Diff line
@@ -12,7 +12,6 @@ 
#include "io_uring.h"

#include "epoll.h"



#if defined(CONFIG_EPOLL)

struct io_epoll {

	struct file			*file;

	int				epfd;
@@ -21,6 +20,12 @@ struct io_epoll { 
	struct epoll_event		event;

};



struct io_epoll_wait {

	struct file			*file;

	int				maxevents;

	struct epoll_event __user	*events;

};



int io_epoll_ctl_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)

{

	struct io_epoll *epoll = io_kiocb_to_cmd(req, struct io_epoll);
@@ -58,4 +63,30 @@ int io_epoll_ctl(struct io_kiocb *req, unsigned int issue_flags) 
	io_req_set_res(req, ret, 0);

	return IOU_OK;

}

#endif
 


int io_epoll_wait_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)

{

	struct io_epoll_wait *iew = io_kiocb_to_cmd(req, struct io_epoll_wait);



	if (sqe->off || sqe->rw_flags || sqe->buf_index || sqe->splice_fd_in)

		return -EINVAL;



	iew->maxevents = READ_ONCE(sqe->len);

	iew->events = u64_to_user_ptr(READ_ONCE(sqe->addr));

	return 0;

}



int io_epoll_wait(struct io_kiocb *req, unsigned int issue_flags)

{

	struct io_epoll_wait *iew = io_kiocb_to_cmd(req, struct io_epoll_wait);

	int ret;



	ret = epoll_sendevents(req->file, iew->events, iew->maxevents);

	if (ret == 0)

		return -EAGAIN;

	if (ret < 0)

		req_set_fail(req);



	io_req_set_res(req, ret, 0);

	return IOU_OK;

}

io_uring/epoll.h

+2 −0
Original line number Diff line number Diff line
@@ -3,4 +3,6 @@ 
#if defined(CONFIG_EPOLL)

int io_epoll_ctl_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);

int io_epoll_ctl(struct io_kiocb *req, unsigned int issue_flags);

int io_epoll_wait_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);

int io_epoll_wait(struct io_kiocb *req, unsigned int issue_flags);

#endif

io_uring/opdef.c

+14 −0
Original line number Diff line number Diff line
@@ -527,6 +527,17 @@ const struct io_issue_def io_issue_defs[] = { 
		.issue			= io_recvzc,

#else

		.prep			= io_eopnotsupp_prep,

#endif

	},

	[IORING_OP_EPOLL_WAIT] = {

		.needs_file		= 1,

		.audit_skip		= 1,

		.pollin			= 1,

#if defined(CONFIG_EPOLL)

		.prep			= io_epoll_wait_prep,

		.issue			= io_epoll_wait,

#else

		.prep			= io_eopnotsupp_prep,

#endif

	},

};
@@ -761,6 +772,9 @@ const struct io_cold_def io_cold_defs[] = { 
	[IORING_OP_RECV_ZC] = {

		.name			= "RECV_ZC",

	},

	[IORING_OP_EPOLL_WAIT] = {

		.name			= "EPOLL_WAIT",

	},

};



const char *io_uring_get_opcode(u8 opcode)