io_uring: move poll handling into its own file

Add a io_poll_issue() rather than export the general task_work locking
and io_issue_sqe(), and put the io_op_defs definition and structure into
a separate header file so that poll can use it.
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring/Makefile

@@ -6,5 +6,5 @@ obj-$(CONFIG_IO_URING)		+= io_uring.o xattr.o nop.o fs.o splice.o \
 					sync.o advise.o filetable.o \
 					openclose.o uring_cmd.o epoll.o \
 					statx.o net.o msg_ring.o timeout.o \
-					sqpoll.o fdinfo.o tctx.o
+					sqpoll.o fdinfo.o tctx.o poll.o
 obj-$(CONFIG_IO_WQ)		+= io-wq.o

io_uring/io_uring.h

@@ -92,6 +92,7 @@ static inline bool io_run_task_work(void)
 	return false;
 }
 
+void io_req_complete_failed(struct io_kiocb *req, s32 res);
 void __io_req_complete(struct io_kiocb *req, unsigned issue_flags);
 void io_req_complete_post(struct io_kiocb *req);
 void __io_req_complete_post(struct io_kiocb *req);
@@ -109,6 +110,32 @@ static inline bool io_do_buffer_select(struct io_kiocb *req)
 	return !(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING));
 }
 
+void __io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags);
+static inline void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
+{
+	if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
+		return;
+	/*
+	 * For legacy provided buffer mode, don't recycle if we already did
+	 * IO to this buffer. For ring-mapped provided buffer mode, we should
+	 * increment ring->head to explicitly monopolize the buffer to avoid
+	 * multiple use.
+	 */
+	if ((req->flags & REQ_F_BUFFER_SELECTED) &&
+	    (req->flags & REQ_F_PARTIAL_IO))
+		return;
+
+	/*
+	 * READV uses fields in `struct io_rw` (len/addr) to stash the selected
+	 * buffer data. However if that buffer is recycled the original request
+	 * data stored in addr is lost. Therefore forbid recycling for now.
+	 */
+	if (req->opcode == IORING_OP_READV)
+		return;
+
+	__io_kbuf_recycle(req, issue_flags);
+}
+
 struct file *io_file_get_normal(struct io_kiocb *req, int fd);
 struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
 			       unsigned issue_flags);
@@ -128,12 +155,14 @@ void io_req_task_work_add(struct io_kiocb *req);
 void io_req_tw_post_queue(struct io_kiocb *req, s32 res, u32 cflags);
 void io_req_task_complete(struct io_kiocb *req, bool *locked);
 void io_req_task_queue_fail(struct io_kiocb *req, int ret);
+void io_req_task_submit(struct io_kiocb *req, bool *locked);
 void tctx_task_work(struct callback_head *cb);
 int io_try_cancel(struct io_kiocb *req, struct io_cancel_data *cd);
 __cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd);
 int io_uring_alloc_task_context(struct task_struct *task,
 				struct io_ring_ctx *ctx);
 
+int io_poll_issue(struct io_kiocb *req, bool *locked);
 int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr);
 int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin);
 
@@ -143,6 +172,9 @@ void io_wq_submit_work(struct io_wq_work *work);
 void io_free_req(struct io_kiocb *req);
 void io_queue_next(struct io_kiocb *req);
 
+bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,
+			bool cancel_all);
+
 #define io_for_each_link(pos, head) \
 	for (pos = (head); pos; pos = pos->link)
 

io_uring/opdef.h

+// SPDX-License-Identifier: GPL-2.0
+#ifndef IOU_OP_DEF_H
+#define IOU_OP_DEF_H
+
+struct io_op_def {
+	/* needs req->file assigned */
+	unsigned		needs_file : 1;
+	/* should block plug */
+	unsigned		plug : 1;
+	/* hash wq insertion if file is a regular file */
+	unsigned		hash_reg_file : 1;
+	/* unbound wq insertion if file is a non-regular file */
+	unsigned		unbound_nonreg_file : 1;
+	/* set if opcode supports polled "wait" */
+	unsigned		pollin : 1;
+	unsigned		pollout : 1;
+	unsigned		poll_exclusive : 1;
+	/* op supports buffer selection */
+	unsigned		buffer_select : 1;
+	/* opcode is not supported by this kernel */
+	unsigned		not_supported : 1;
+	/* skip auditing */
+	unsigned		audit_skip : 1;
+	/* supports ioprio */
+	unsigned		ioprio : 1;
+	/* supports iopoll */
+	unsigned		iopoll : 1;
+	/* size of async data needed, if any */
+	unsigned short		async_size;
+
+	const char		*name;
+
+	int (*prep)(struct io_kiocb *, const struct io_uring_sqe *);
+	int (*issue)(struct io_kiocb *, unsigned int);
+	int (*prep_async)(struct io_kiocb *);
+	void (*cleanup)(struct io_kiocb *);
+};
+
+extern const struct io_op_def io_op_defs[];
+#endif

io_uring/poll.h

+// SPDX-License-Identifier: GPL-2.0
+
+enum {
+	IO_APOLL_OK,
+	IO_APOLL_ABORTED,
+	IO_APOLL_READY
+};
+
+struct io_poll {
+	struct file			*file;
+	struct wait_queue_head		*head;
+	__poll_t			events;
+	struct wait_queue_entry		wait;
+};
+
+struct async_poll {
+	struct io_poll		poll;
+	struct io_poll		*double_poll;
+};
+
+int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
+int io_poll_add(struct io_kiocb *req, unsigned int issue_flags);
+
+int io_poll_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
+int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags);
+
+int io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd);
+int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags);
+bool io_poll_remove_all(struct io_ring_ctx *ctx, struct task_struct *tsk,
+			bool cancel_all);