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>

6 files changed, 879 insertions, 827 deletions

diff --git a/io_uring/Makefile b/io_uring/Makefile
index 2db085cdedad..eb1b07a99516 100644
--- a/io_uring/Makefile
+++ b/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
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 3f006907c8c5..b4ecfa723855 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -88,6 +88,7 @@
 
 #include "io_uring_types.h"
 #include "io_uring.h"
+#include "opdef.h"
 #include "refs.h"
 #include "tctx.h"
 #include "sqpoll.h"
@@ -106,6 +107,7 @@
 #include "net.h"
 #include "msg_ring.h"
 #include "timeout.h"
+#include "poll.h"
 
 #define IORING_MAX_ENTRIES	32768
 #define IORING_MAX_CQ_ENTRIES	(2 * IORING_MAX_ENTRIES)
@@ -208,22 +210,6 @@ struct io_buffer {
  * First field must be the file pointer in all the
  * iocb unions! See also 'struct kiocb' in <linux/fs.h>
  */
-struct io_poll {
-	struct file			*file;
-	struct wait_queue_head		*head;
-	__poll_t			events;
-	struct wait_queue_entry		wait;
-};
-
-struct io_poll_update {
-	struct file			*file;
-	u64				old_user_data;
-	u64				new_user_data;
-	__poll_t			events;
-	bool				update_events;
-	bool				update_user_data;
-};
-
 struct io_cancel {
 	struct file			*file;
 	u64				addr;
@@ -268,11 +254,6 @@ struct io_async_rw {
 	struct wait_page_queue		wpq;
 };
 
-struct async_poll {
-	struct io_poll		poll;
-	struct io_poll		*double_poll;
-};
-
 enum {
 	IORING_RSRC_FILE		= 0,
 	IORING_RSRC_BUFFER		= 1,
@@ -289,42 +270,6 @@ struct io_defer_entry {
 	u32			seq;
 };
 
-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 *);
-};
-
-static const struct io_op_def io_op_defs[];
-
 /* requests with any of those set should undergo io_disarm_next() */
 #define IO_DISARM_MASK (REQ_F_ARM_LTIMEOUT | REQ_F_LINK_TIMEOUT | REQ_F_FAIL)
 #define IO_REQ_LINK_FLAGS (REQ_F_LINK | REQ_F_HARDLINK)
@@ -529,32 +474,12 @@ static struct io_buffer_list *io_buffer_get_list(struct io_ring_ctx *ctx,
 	return xa_load(&ctx->io_bl_xa, bgid);
 }
 
-static void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
+void __io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags)
 {
 	struct io_ring_ctx *ctx = req->ctx;
 	struct io_buffer_list *bl;
 	struct io_buffer *buf;
 
-	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;
-
 	/*
 	 * We don't need to recycle for REQ_F_BUFFER_RING, we can just clear
 	 * the flag and hence ensure that bl->head doesn't get incremented.
@@ -599,8 +524,8 @@ static bool io_match_linked(struct io_kiocb *head)
  * As io_match_task() but protected against racing with linked timeouts.
  * User must not hold timeout_lock.
  */
-static bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,
-			       bool cancel_all)
+bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,
+			bool cancel_all)
 {
 	bool matched;
 
@@ -1310,7 +1235,7 @@ inline void __io_req_complete(struct io_kiocb *req, unsigned issue_flags)
 		io_req_complete_post(req);
 }
 
-static void io_req_complete_failed(struct io_kiocb *req, s32 res)
+void io_req_complete_failed(struct io_kiocb *req, s32 res)
 {
 	req_set_fail(req);
 	io_req_set_res(req, res, io_put_kbuf(req, IO_URING_F_UNLOCKED));
@@ -1656,7 +1581,7 @@ static void io_req_task_cancel(struct io_kiocb *req, bool *locked)
 	io_req_complete_failed(req, req->cqe.res);
 }
 
-static void io_req_task_submit(struct io_kiocb *req, bool *locked)
+void io_req_task_submit(struct io_kiocb *req, bool *locked)
 {
 	io_tw_lock(req->ctx, locked);
 	/* req->task == current here, checking PF_EXITING is safe */
@@ -3437,749 +3362,6 @@ static __maybe_unused int io_eopnotsupp_prep(struct io_kiocb *kiocb,
 	return -EOPNOTSUPP;
 }
 
-struct io_poll_table {
-	struct poll_table_struct pt;
-	struct io_kiocb *req;
-	int nr_entries;
-	int error;
-};
-
-#define IO_POLL_CANCEL_FLAG	BIT(31)
-#define IO_POLL_REF_MASK	GENMASK(30, 0)
-
-/*
- * If refs part of ->poll_refs (see IO_POLL_REF_MASK) is 0, it's free. We can
- * bump it and acquire ownership. It's disallowed to modify requests while not
- * owning it, that prevents from races for enqueueing task_work's and b/w
- * arming poll and wakeups.
- */
-static inline bool io_poll_get_ownership(struct io_kiocb *req)
-{
-	return !(atomic_fetch_inc(&req->poll_refs) & IO_POLL_REF_MASK);
-}
-
-static void io_poll_mark_cancelled(struct io_kiocb *req)
-{
-	atomic_or(IO_POLL_CANCEL_FLAG, &req->poll_refs);
-}
-
-static struct io_poll *io_poll_get_double(struct io_kiocb *req)
-{
-	/* pure poll stashes this in ->async_data, poll driven retry elsewhere */
-	if (req->opcode == IORING_OP_POLL_ADD)
-		return req->async_data;
-	return req->apoll->double_poll;
-}
-
-static struct io_poll *io_poll_get_single(struct io_kiocb *req)
-{
-	if (req->opcode == IORING_OP_POLL_ADD)
-		return io_kiocb_to_cmd(req);
-	return &req->apoll->poll;
-}
-
-static void io_poll_req_insert(struct io_kiocb *req)
-{
-	struct io_ring_ctx *ctx = req->ctx;
-	struct hlist_head *list;
-
-	list = &ctx->cancel_hash[hash_long(req->cqe.user_data, ctx->cancel_hash_bits)];
-	hlist_add_head(&req->hash_node, list);
-}
-
-static void io_init_poll_iocb(struct io_poll *poll, __poll_t events,
-			      wait_queue_func_t wake_func)
-{
-	poll->head = NULL;
-#define IO_POLL_UNMASK	(EPOLLERR|EPOLLHUP|EPOLLNVAL|EPOLLRDHUP)
-	/* mask in events that we always want/need */
-	poll->events = events | IO_POLL_UNMASK;
-	INIT_LIST_HEAD(&poll->wait.entry);
-	init_waitqueue_func_entry(&poll->wait, wake_func);
-}
-
-static inline void io_poll_remove_entry(struct io_poll *poll)
-{
-	struct wait_queue_head *head = smp_load_acquire(&poll->head);
-
-	if (head) {
-		spin_lock_irq(&head->lock);
-		list_del_init(&poll->wait.entry);
-		poll->head = NULL;
-		spin_unlock_irq(&head->lock);
-	}
-}
-
-static void io_poll_remove_entries(struct io_kiocb *req)
-{
-	/*
-	 * Nothing to do if neither of those flags are set. Avoid dipping
-	 * into the poll/apoll/double cachelines if we can.
-	 */
-	if (!(req->flags & (REQ_F_SINGLE_POLL | REQ_F_DOUBLE_POLL)))
-		return;
-
-	/*
-	 * While we hold the waitqueue lock and the waitqueue is nonempty,
-	 * wake_up_pollfree() will wait for us.  However, taking the waitqueue
-	 * lock in the first place can race with the waitqueue being freed.
-	 *
-	 * We solve this as eventpoll does: by taking advantage of the fact that
-	 * all users of wake_up_pollfree() will RCU-delay the actual free.  If
-	 * we enter rcu_read_lock() and see that the pointer to the queue is
-	 * non-NULL, we can then lock it without the memory being freed out from
-	 * under us.
-	 *
-	 * Keep holding rcu_read_lock() as long as we hold the queue lock, in
-	 * case the caller deletes the entry from the queue, leaving it empty.
-	 * In that case, only RCU prevents the queue memory from being freed.
-	 */
-	rcu_read_lock();
-	if (req->flags & REQ_F_SINGLE_POLL)
-		io_poll_remove_entry(io_poll_get_single(req));
-	if (req->flags & REQ_F_DOUBLE_POLL)
-		io_poll_remove_entry(io_poll_get_double(req));
-	rcu_read_unlock();
-}
-
-static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags);
-/*
- * All poll tw should go through this. Checks for poll events, manages
- * references, does rewait, etc.
- *
- * Returns a negative error on failure. >0 when no action require, which is
- * either spurious wakeup or multishot CQE is served. 0 when it's done with
- * the request, then the mask is stored in req->cqe.res.
- */
-static int io_poll_check_events(struct io_kiocb *req, bool *locked)
-{
-	struct io_ring_ctx *ctx = req->ctx;
-	int v, ret;
-
-	/* req->task == current here, checking PF_EXITING is safe */
-	if (unlikely(req->task->flags & PF_EXITING))
-		return -ECANCELED;
-
-	do {
-		v = atomic_read(&req->poll_refs);
-
-		/* tw handler should be the owner, and so have some references */
-		if (WARN_ON_ONCE(!(v & IO_POLL_REF_MASK)))
-			return 0;
-		if (v & IO_POLL_CANCEL_FLAG)
-			return -ECANCELED;
-
-		if (!req->cqe.res) {
-			struct poll_table_struct pt = { ._key = req->apoll_events };
-			req->cqe.res = vfs_poll(req->file, &pt) & req->apoll_events;
-		}
-
-		if ((unlikely(!req->cqe.res)))
-			continue;
-		if (req->apoll_events & EPOLLONESHOT)
-			return 0;
-
-		/* multishot, just fill a CQE and proceed */
-		if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
-			__poll_t mask = mangle_poll(req->cqe.res &
-						    req->apoll_events);
-			bool filled;
-
-			spin_lock(&ctx->completion_lock);
-			filled = io_fill_cqe_aux(ctx, req->cqe.user_data,
-						 mask, IORING_CQE_F_MORE);
-			io_commit_cqring(ctx);
-			spin_unlock(&ctx->completion_lock);
-			if (filled) {
-				io_cqring_ev_posted(ctx);
-				continue;
-			}
-			return -ECANCELED;
-		}
-
-		io_tw_lock(req->ctx, locked);
-		if (unlikely(req->task->flags & PF_EXITING))
-			return -EFAULT;
-		ret = io_issue_sqe(req,
-				   IO_URING_F_NONBLOCK|IO_URING_F_COMPLETE_DEFER);
-		if (ret)
-			return ret;
-
-		/*
-		 * Release all references, retry if someone tried to restart
-		 * task_work while we were executing it.
-		 */
-	} while (atomic_sub_return(v & IO_POLL_REF_MASK, &req->poll_refs));
-
-	return 1;
-}
-
-static void io_poll_task_func(struct io_kiocb *req, bool *locked)
-{
-	struct io_ring_ctx *ctx = req->ctx;
-	int ret;
-
-	ret = io_poll_check_events(req, locked);
-	if (ret > 0)
-		return;
-
-	if (!ret) {
-		struct io_poll *poll = io_kiocb_to_cmd(req);
-
-		req->cqe.res = mangle_poll(req->cqe.res & poll->events);
-	} else {
-		req->cqe.res = ret;
-		req_set_fail(req);
-	}
-
-	io_poll_remove_entries(req);
-	spin_lock(&ctx->completion_lock);
-	hash_del(&req->hash_node);
-	req->cqe.flags = 0;
-	__io_req_complete_post(req);
-	io_commit_cqring(ctx);
-	spin_unlock(&ctx->completion_lock);
-	io_cqring_ev_posted(ctx);
-}
-
-static void io_apoll_task_func(struct io_kiocb *req, bool *locked)
-{
-	struct io_ring_ctx *ctx = req->ctx;
-	int ret;
-
-	ret = io_poll_check_events(req, locked);
-	if (ret > 0)
-		return;
-
-	io_poll_remove_entries(req);
-	spin_lock(&ctx->completion_lock);
-	hash_del(&req->hash_node);
-	spin_unlock(&ctx->completion_lock);
-
-	if (!ret)
-		io_req_task_submit(req, locked);
-	else
-		io_req_complete_failed(req, ret);
-}
-
-static void __io_poll_execute(struct io_kiocb *req, int mask,
-			      __poll_t __maybe_unused events)
-{
-	io_req_set_res(req, mask, 0);
-	/*
-	 * This is useful for poll that is armed on behalf of another
-	 * request, and where the wakeup path could be on a different
-	 * CPU. We want to avoid pulling in req->apoll->events for that
-	 * case.
-	 */
-	if (req->opcode == IORING_OP_POLL_ADD)
-		req->io_task_work.func = io_poll_task_func;
-	else
-		req->io_task_work.func = io_apoll_task_func;
-
-	trace_io_uring_task_add(req->ctx, req, req->cqe.user_data, req->opcode, mask);
-	io_req_task_work_add(req);
-}
-
-static inline void io_poll_execute(struct io_kiocb *req, int res,
-		__poll_t events)
-{
-	if (io_poll_get_ownership(req))
-		__io_poll_execute(req, res, events);
-}
-
-static void io_poll_cancel_req(struct io_kiocb *req)
-{
-	io_poll_mark_cancelled(req);
-	/* kick tw, which should complete the request */
-	io_poll_execute(req, 0, 0);
-}
-
-#define wqe_to_req(wait)	((void *)((unsigned long) (wait)->private & ~1))
-#define wqe_is_double(wait)	((unsigned long) (wait)->private & 1)
-#define IO_ASYNC_POLL_COMMON	(EPOLLONESHOT | EPOLLPRI)
-
-static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
-			void *key)
-{
-	struct io_kiocb *req = wqe_to_req(wait);
-	struct io_poll *poll = container_of(wait, struct io_poll, wait);
-	__poll_t mask = key_to_poll(key);
-
-	if (unlikely(mask & POLLFREE)) {
-		io_poll_mark_cancelled(req);
-		/* we have to kick tw in case it's not already */
-		io_poll_execute(req, 0, poll->events);
-
-		/*
-		 * If the waitqueue is being freed early but someone is already
-		 * holds ownership over it, we have to tear down the request as
-		 * best we can. That means immediately removing the request from
-		 * its waitqueue and preventing all further accesses to the
-		 * waitqueue via the request.
-		 */
-		list_del_init(&poll->wait.entry);
-
-		/*
-		 * Careful: this *must* be the last step, since as soon
-		 * as req->head is NULL'ed out, the request can be
-		 * completed and freed, since aio_poll_complete_work()
-		 * will no longer need to take the waitqueue lock.
-		 */
-		smp_store_release(&poll->head, NULL);
-		return 1;
-	}
-
-	/* for instances that support it check for an event match first */
-	if (mask && !(mask & (poll->events & ~IO_ASYNC_POLL_COMMON)))
-		return 0;
-
-	if (io_poll_get_ownership(req)) {
-		/* optional, saves extra locking for removal in tw handler */
-		if (mask && poll->events & EPOLLONESHOT) {
-			list_del_init(&poll->wait.entry);
-			poll->head = NULL;
-			if (wqe_is_double(wait))
-				req->flags &= ~REQ_F_DOUBLE_POLL;
-			else
-				req->flags &= ~REQ_F_SINGLE_POLL;
-		}
-		__io_poll_execute(req, mask, poll->events);
-	}
-	return 1;
-}
-
-static void __io_queue_proc(struct io_poll *poll, struct io_poll_table *pt,
-			    struct wait_queue_head *head,
-			    struct io_poll **poll_ptr)
-{
-	struct io_kiocb *req = pt->req;
-	unsigned long wqe_private = (unsigned long) req;
-
-	/*
-	 * The file being polled uses multiple waitqueues for poll handling
-	 * (e.g. one for read, one for write). Setup a separate io_poll
-	 * if this happens.
-	 */
-	if (unlikely(pt->nr_entries)) {
-		struct io_poll *first = poll;
-
-		/* double add on the same waitqueue head, ignore */
-		if (first->head == head)
-			return;
-		/* already have a 2nd entry, fail a third attempt */
-		if (*poll_ptr) {
-			if ((*poll_ptr)->head == head)
-				return;
-			pt->error = -EINVAL;
-			return;
-		}
-
-		poll = kmalloc(sizeof(*poll), GFP_ATOMIC);
-		if (!poll) {
-			pt->error = -ENOMEM;
-			return;
-		}
-		/* mark as double wq entry */
-		wqe_private |= 1;
-		req->flags |= REQ_F_DOUBLE_POLL;
-		io_init_poll_iocb(poll, first->events, first->wait.func);
-		*poll_ptr = poll;
-		if (req->opcode == IORING_OP_POLL_ADD)
-			req->flags |= REQ_F_ASYNC_DATA;
-	}
-
-	req->flags |= REQ_F_SINGLE_POLL;
-	pt->nr_entries++;
-	poll->head = head;
-	poll->wait.private = (void *) wqe_private;
-
-	if (poll->events & EPOLLEXCLUSIVE)
-		add_wait_queue_exclusive(head, &poll->wait);
-	else
-		add_wait_queue(head, &poll->wait);
-}
-
-static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head,
-			       struct poll_table_struct *p)
-{
-	struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
-	struct io_poll *poll = io_kiocb_to_cmd(pt->req);
-
-	__io_queue_proc(poll, pt, head,
-			(struct io_poll **) &pt->req->async_data);
-}
-
-static int __io_arm_poll_handler(struct io_kiocb *req,
-				 struct io_poll *poll,
-				 struct io_poll_table *ipt, __poll_t mask)
-{
-	struct io_ring_ctx *ctx = req->ctx;
-	int v;
-
-	INIT_HLIST_NODE(&req->hash_node);
-	req->work.cancel_seq = atomic_read(&ctx->cancel_seq);
-	io_init_poll_iocb(poll, mask, io_poll_wake);
-	poll->file = req->file;
-
-	req->apoll_events = poll->events;
-
-	ipt->pt._key = mask;
-	ipt->req = req;
-	ipt->error = 0;
-	ipt->nr_entries = 0;
-
-	/*
-	 * Take the ownership to delay any tw execution up until we're done
-	 * with poll arming. see io_poll_get_ownership().
-	 */
-	atomic_set(&req->poll_refs, 1);
-	mask = vfs_poll(req->file, &ipt->pt) & poll->events;
-
-	if (mask && (poll->events & EPOLLONESHOT)) {
-		io_poll_remove_entries(req);
-		/* no one else has access to the req, forget about the ref */
-		return mask;
-	}
-	if (!mask && unlikely(ipt->error || !ipt->nr_entries)) {
-		io_poll_remove_entries(req);
-		if (!ipt->error)
-			ipt->error = -EINVAL;
-		return 0;
-	}
-
-	spin_lock(&ctx->completion_lock);
-	io_poll_req_insert(req);
-	spin_unlock(&ctx->completion_lock);
-
-	if (mask) {
-		/* can't multishot if failed, just queue the event we've got */
-		if (unlikely(ipt->error || !ipt->nr_entries)) {
-			poll->events |= EPOLLONESHOT;
-			req->apoll_events |= EPOLLONESHOT;
-			ipt->error = 0;
-		}
-		__io_poll_execute(req, mask, poll->events);
-		return 0;
-	}
-
-	/*
-	 * Release ownership. If someone tried to queue a tw while it was
-	 * locked, kick it off for them.
-	 */
-	v = atomic_dec_return(&req->poll_refs);
-	if (unlikely(v & IO_POLL_REF_MASK))
-		__io_poll_execute(req, 0, poll->events);
-	return 0;
-}
-
-static void io_async_queue_proc(struct file *file, struct wait_queue_head *head,
-			       struct poll_table_struct *p)
-{
-	struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
-	struct async_poll *apoll = pt->req->apoll;
-
-	__io_queue_proc(&apoll->poll, pt, head, &apoll->double_poll);
-}
-
-enum {
-	IO_APOLL_OK,
-	IO_APOLL_ABORTED,
-	IO_APOLL_READY
-};
-
-static int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags)
-{
-	const struct io_op_def *def = &io_op_defs[req->opcode];
-	struct io_ring_ctx *ctx = req->ctx;
-	struct async_poll *apoll;
-	struct io_poll_table ipt;
-	__poll_t mask = POLLPRI | POLLERR;
-	int ret;
-
-	if (!def->pollin && !def->pollout)
-		return IO_APOLL_ABORTED;
-	if (!file_can_poll(req->file))
-		return IO_APOLL_ABORTED;
-	if ((req->flags & (REQ_F_POLLED|REQ_F_PARTIAL_IO)) == REQ_F_POLLED)
-		return IO_APOLL_ABORTED;
-	if (!(req->flags & REQ_F_APOLL_MULTISHOT))
-		mask |= EPOLLONESHOT;
-
-	if (def->pollin) {
-		mask |= EPOLLIN | EPOLLRDNORM;
-
-		/* If reading from MSG_ERRQUEUE using recvmsg, ignore POLLIN */
-		if (req->flags & REQ_F_CLEAR_POLLIN)
-			mask &= ~EPOLLIN;
-	} else {
-		mask |= EPOLLOUT | EPOLLWRNORM;
-	}
-	if (def->poll_exclusive)
-		mask |= EPOLLEXCLUSIVE;
-	if (req->flags & REQ_F_POLLED) {
-		apoll = req->apoll;
-		kfree(apoll->double_poll);
-	} else if (!(issue_flags & IO_URING_F_UNLOCKED) &&
-		   !list_empty(&ctx->apoll_cache)) {
-		apoll = list_first_entry(&ctx->apoll_cache, struct async_poll,
-						poll.wait.entry);
-		list_del_init(&apoll->poll.wait.entry);
-	} else {
-		apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
-		if (unlikely(!apoll))
-			return IO_APOLL_ABORTED;
-	}
-	apoll->double_poll = NULL;
-	req->apoll = apoll;
-	req->flags |= REQ_F_POLLED;
-	ipt.pt._qproc = io_async_queue_proc;
-
-	io_kbuf_recycle(req, issue_flags);
-
-	ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask);
-	if (ret || ipt.error)
-		return ret ? IO_APOLL_READY : IO_APOLL_ABORTED;
-
-	trace_io_uring_poll_arm(ctx, req, req->cqe.user_data, req->opcode,
-				mask, apoll->poll.events);
-	return IO_APOLL_OK;
-}
-
-/*
- * Returns true if we found and killed one or more poll requests
- */
-static __cold bool io_poll_remove_all(struct io_ring_ctx *ctx,
-				      struct task_struct *tsk, bool cancel_all)
-{
-	struct hlist_node *tmp;
-	struct io_kiocb *req;
-	bool found = false;
-	int i;
-
-	spin_lock(&ctx->completion_lock);
-	for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
-		struct hlist_head *list;
-
-		list = &ctx->cancel_hash[i];
-		hlist_for_each_entry_safe(req, tmp, list, hash_node) {
-			if (io_match_task_safe(req, tsk, cancel_all)) {
-				hlist_del_init(&req->hash_node);
-				io_poll_cancel_req(req);
-				found = true;
-			}
-		}
-	}
-	spin_unlock(&ctx->completion_lock);
-	return found;
-}
-
-static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, bool poll_only,
-				     struct io_cancel_data *cd)
-	__must_hold(&ctx->completion_lock)
-{
-	struct hlist_head *list;
-	struct io_kiocb *req;
-
-	list = &ctx->cancel_hash[hash_long(cd->data, ctx->cancel_hash_bits)];
-	hlist_for_each_entry(req, list, hash_node) {
-		if (cd->data != req->cqe.user_data)
-			continue;
-		if (poll_only && req->opcode != IORING_OP_POLL_ADD)
-			continue;
-		if (cd->flags & IORING_ASYNC_CANCEL_ALL) {
-			if (cd->seq == req->work.cancel_seq)
-				continue;
-			req->work.cancel_seq = cd->seq;
-		}
-		return req;
-	}
-	return NULL;
-}
-
-static struct io_kiocb *io_poll_file_find(struct io_ring_ctx *ctx,
-					  struct io_cancel_data *cd)
-	__must_hold(&ctx->completion_lock)
-{
-	struct io_kiocb *req;
-	int i;
-
-	for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
-		struct hlist_head *list;
-
-		list = &ctx->cancel_hash[i];
-		hlist_for_each_entry(req, list, hash_node) {
-			if (!(cd->flags & IORING_ASYNC_CANCEL_ANY) &&
-			    req->file != cd->file)
-				continue;
-			if (cd->seq == req->work.cancel_seq)
-				continue;
-			req->work.cancel_seq = cd->seq;
-			return req;
-		}
-	}
-	return NULL;
-}
-
-static bool io_poll_disarm(struct io_kiocb *req)
-	__must_hold(&ctx->completion_lock)
-{
-	if (!io_poll_get_ownership(req))
-		return false;
-	io_poll_remove_entries(req);
-	hash_del(&req->hash_node);
-	return true;
-}
-
-static int io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd)
-	__must_hold(&ctx->completion_lock)
-{
-	struct io_kiocb *req;
-
-	if (cd->flags & (IORING_ASYNC_CANCEL_FD|IORING_ASYNC_CANCEL_ANY))
-		req = io_poll_file_find(ctx, cd);
-	else
-		req = io_poll_find(ctx, false, cd);
-	if (!req)
-		return -ENOENT;
-	io_poll_cancel_req(req);
-	return 0;
-}
-
-static __poll_t io_poll_parse_events(const struct io_uring_sqe *sqe,
-				     unsigned int flags)
-{
-	u32 events;
-
-	events = READ_ONCE(sqe->poll32_events);
-#ifdef __BIG_ENDIAN
-	events = swahw32(events);
-#endif
-	if (!(flags & IORING_POLL_ADD_MULTI))
-		events |= EPOLLONESHOT;
-	return demangle_poll(events) | (events & (EPOLLEXCLUSIVE|EPOLLONESHOT));
-}
-
-static int io_poll_remove_prep(struct io_kiocb *req,
-			       const struct io_uring_sqe *sqe)
-{
-	struct io_poll_update *upd = io_kiocb_to_cmd(req);
-	u32 flags;
-
-	if (sqe->buf_index || sqe->splice_fd_in)
-		return -EINVAL;
-	flags = READ_ONCE(sqe->len);
-	if (flags & ~(IORING_POLL_UPDATE_EVENTS | IORING_POLL_UPDATE_USER_DATA |
-		      IORING_POLL_ADD_MULTI))
-		return -EINVAL;
-	/* meaningless without update */
-	if (flags == IORING_POLL_ADD_MULTI)
-		return -EINVAL;
-
-	upd->old_user_data = READ_ONCE(sqe->addr);
-	upd->update_events = flags & IORING_POLL_UPDATE_EVENTS;
-	upd->update_user_data = flags & IORING_POLL_UPDATE_USER_DATA;
-
-	upd->new_user_data = READ_ONCE(sqe->off);
-	if (!upd->update_user_data && upd->new_user_data)
-		return -EINVAL;
-	if (upd->update_events)
-		upd->events = io_poll_parse_events(sqe, flags);
-	else if (sqe->poll32_events)
-		return -EINVAL;
-
-	return 0;
-}
-
-static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
-{
-	struct io_poll *poll = io_kiocb_to_cmd(req);
-	u32 flags;
-
-	if (sqe->buf_index || sqe->off || sqe->addr)
-		return -EINVAL;
-	flags = READ_ONCE(sqe->len);
-	if (flags & ~IORING_POLL_ADD_MULTI)
-		return -EINVAL;
-	if ((flags & IORING_POLL_ADD_MULTI) && (req->flags & REQ_F_CQE_SKIP))
-		return -EINVAL;
-
-	io_req_set_refcount(req);
-	poll->events = io_poll_parse_events(sqe, flags);
-	return 0;
-}
-
-static int io_poll_add(struct io_kiocb *req, unsigned int issue_flags)
-{
-	struct io_poll *poll = io_kiocb_to_cmd(req);
-	struct io_poll_table ipt;
-	int ret;
-
-	ipt.pt._qproc = io_poll_queue_proc;
-
-	ret = __io_arm_poll_handler(req, poll, &ipt, poll->events);
-	if (ret) {
-		io_req_set_res(req, ret, 0);
-		return IOU_OK;
-	}
-	if (ipt.error) {
-		req_set_fail(req);
-		return ipt.error;
-	}
-
-	return IOU_ISSUE_SKIP_COMPLETE;
-}
-
-static int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags)
-{
-	struct io_poll_update *poll_update = io_kiocb_to_cmd(req);
-	struct io_cancel_data cd = { .data = poll_update->old_user_data, };
-	struct io_ring_ctx *ctx = req->ctx;
-	struct io_kiocb *preq;
-	int ret2, ret = 0;
-	bool locked;
-
-	spin_lock(&ctx->completion_lock);
-	preq = io_poll_find(ctx, true, &cd);
-	if (!preq || !io_poll_disarm(preq)) {
-		spin_unlock(&ctx->completion_lock);
-		ret = preq ? -EALREADY : -ENOENT;
-		goto out;
-	}
-	spin_unlock(&ctx->completion_lock);
-
-	if (poll_update->update_events || poll_update->update_user_data) {
-		/* only mask one event flags, keep behavior flags */
-		if (poll_update->update_events) {
-			struct io_poll *poll = io_kiocb_to_cmd(preq);
-
-			poll->events &= ~0xffff;
-			poll->events |= poll_update->events & 0xffff;
-			poll->events |= IO_POLL_UNMASK;
-		}
-		if (poll_update->update_user_data)
-			preq->cqe.user_data = poll_update->new_user_data;
-
-		ret2 = io_poll_add(preq, issue_flags);
-		/* successfully updated, don't complete poll request */
-		if (!ret2 || ret2 == -EIOCBQUEUED)
-			goto out;
-	}
-
-	req_set_fail(preq);
-	io_req_set_res(preq, -ECANCELED, 0);
-	locked = !(issue_flags & IO_URING_F_UNLOCKED);
-	io_req_task_complete(preq, &locked);
-out:
-	if (ret < 0) {
-		req_set_fail(req);
-		return ret;
-	}
-	/* complete update request, we're done with it */
-	io_req_set_res(req, ret, 0);
-	return IOU_OK;
-}
-
 static bool io_cancel_cb(struct io_wq_work *work, void *data)
 {
 	struct io_kiocb *req = container_of(work, struct io_kiocb, work);
@@ -4589,6 +3771,14 @@ static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
 	return 0;
 }
 
+int io_poll_issue(struct io_kiocb *req, bool *locked)
+{
+	io_tw_lock(req->ctx, locked);
+	if (unlikely(req->task->flags & PF_EXITING))
+		return -EFAULT;
+	return io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_COMPLETE_DEFER);
+}
+
 struct io_wq_work *io_wq_free_work(struct io_wq_work *work)
 {
 	struct io_kiocb *req = container_of(work, struct io_kiocb, work);
@@ -8209,7 +7399,7 @@ static int io_no_issue(struct io_kiocb *req, unsigned int issue_flags)
 	return -ECANCELED;
 }
 
-static const struct io_op_def io_op_defs[] = {
+const struct io_op_def io_op_defs[] = {
 	[IORING_OP_NOP] = {
 		.audit_skip		= 1,
 		.iopoll			= 1,
diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h
index 60678e88a9b9..1ceac4ea62bf 100644
--- a/io_uring/io_uring.h
+++ b/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)
 
diff --git a/io_uring/opdef.h b/io_uring/opdef.h
new file mode 100644
index 000000000000..4578adcdba8a
--- /dev/null
+++ b/io_uring/opdef.h
@@ -0,0 +1,40 @@
+// 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
diff --git a/io_uring/poll.c b/io_uring/poll.c
new file mode 100644
index 000000000000..c3e4fcb0a7ba
--- /dev/null
+++ b/io_uring/poll.c
@@ -0,0 +1,760 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/poll.h>
+#include <linux/hashtable.h>
+#include <linux/io_uring.h>
+
+#include <trace/events/io_uring.h>
+
+#include <uapi/linux/io_uring.h>
+
+#include "io_uring_types.h"
+#include "io_uring.h"
+#include "refs.h"
+#include "opdef.h"
+#include "poll.h"
+
+struct io_poll_update {
+	struct file			*file;
+	u64				old_user_data;
+	u64				new_user_data;
+	__poll_t			events;
+	bool				update_events;
+	bool				update_user_data;
+};
+
+struct io_poll_table {
+	struct poll_table_struct pt;
+	struct io_kiocb *req;
+	int nr_entries;
+	int error;
+};
+
+#define IO_POLL_CANCEL_FLAG	BIT(31)
+#define IO_POLL_REF_MASK	GENMASK(30, 0)
+
+/*
+ * If refs part of ->poll_refs (see IO_POLL_REF_MASK) is 0, it's free. We can
+ * bump it and acquire ownership. It's disallowed to modify requests while not
+ * owning it, that prevents from races for enqueueing task_work's and b/w
+ * arming poll and wakeups.
+ */
+static inline bool io_poll_get_ownership(struct io_kiocb *req)
+{
+	return !(atomic_fetch_inc(&req->poll_refs) & IO_POLL_REF_MASK);
+}
+
+static void io_poll_mark_cancelled(struct io_kiocb *req)
+{
+	atomic_or(IO_POLL_CANCEL_FLAG, &req->poll_refs);
+}
+
+static struct io_poll *io_poll_get_double(struct io_kiocb *req)
+{
+	/* pure poll stashes this in ->async_data, poll driven retry elsewhere */
+	if (req->opcode == IORING_OP_POLL_ADD)
+		return req->async_data;
+	return req->apoll->double_poll;
+}
+
+static struct io_poll *io_poll_get_single(struct io_kiocb *req)
+{
+	if (req->opcode == IORING_OP_POLL_ADD)
+		return io_kiocb_to_cmd(req);
+	return &req->apoll->poll;
+}
+
+static void io_poll_req_insert(struct io_kiocb *req)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	struct hlist_head *list;
+
+	list = &ctx->cancel_hash[hash_long(req->cqe.user_data, ctx->cancel_hash_bits)];
+	hlist_add_head(&req->hash_node, list);
+}
+
+static void io_init_poll_iocb(struct io_poll *poll, __poll_t events,
+			      wait_queue_func_t wake_func)
+{
+	poll->head = NULL;
+#define IO_POLL_UNMASK	(EPOLLERR|EPOLLHUP|EPOLLNVAL|EPOLLRDHUP)
+	/* mask in events that we always want/need */
+	poll->events = events | IO_POLL_UNMASK;
+	INIT_LIST_HEAD(&poll->wait.entry);
+	init_waitqueue_func_entry(&poll->wait, wake_func);
+}
+
+static inline void io_poll_remove_entry(struct io_poll *poll)
+{
+	struct wait_queue_head *head = smp_load_acquire(&poll->head);
+
+	if (head) {
+		spin_lock_irq(&head->lock);
+		list_del_init(&poll->wait.entry);
+		poll->head = NULL;
+		spin_unlock_irq(&head->lock);
+	}
+}
+
+static void io_poll_remove_entries(struct io_kiocb *req)
+{
+	/*
+	 * Nothing to do if neither of those flags are set. Avoid dipping
+	 * into the poll/apoll/double cachelines if we can.
+	 */
+	if (!(req->flags & (REQ_F_SINGLE_POLL | REQ_F_DOUBLE_POLL)))
+		return;
+
+	/*
+	 * While we hold the waitqueue lock and the waitqueue is nonempty,
+	 * wake_up_pollfree() will wait for us.  However, taking the waitqueue
+	 * lock in the first place can race with the waitqueue being freed.
+	 *
+	 * We solve this as eventpoll does: by taking advantage of the fact that
+	 * all users of wake_up_pollfree() will RCU-delay the actual free.  If
+	 * we enter rcu_read_lock() and see that the pointer to the queue is
+	 * non-NULL, we can then lock it without the memory being freed out from
+	 * under us.
+	 *
+	 * Keep holding rcu_read_lock() as long as we hold the queue lock, in
+	 * case the caller deletes the entry from the queue, leaving it empty.
+	 * In that case, only RCU prevents the queue memory from being freed.
+	 */
+	rcu_read_lock();
+	if (req->flags & REQ_F_SINGLE_POLL)
+		io_poll_remove_entry(io_poll_get_single(req));
+	if (req->flags & REQ_F_DOUBLE_POLL)
+		io_poll_remove_entry(io_poll_get_double(req));
+	rcu_read_unlock();
+}
+
+/*
+ * All poll tw should go through this. Checks for poll events, manages
+ * references, does rewait, etc.
+ *
+ * Returns a negative error on failure. >0 when no action require, which is
+ * either spurious wakeup or multishot CQE is served. 0 when it's done with
+ * the request, then the mask is stored in req->cqe.res.
+ */
+static int io_poll_check_events(struct io_kiocb *req, bool *locked)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	int v, ret;
+
+	/* req->task == current here, checking PF_EXITING is safe */
+	if (unlikely(req->task->flags & PF_EXITING))
+		return -ECANCELED;
+
+	do {
+		v = atomic_read(&req->poll_refs);
+
+		/* tw handler should be the owner, and so have some references */
+		if (WARN_ON_ONCE(!(v & IO_POLL_REF_MASK)))
+			return 0;
+		if (v & IO_POLL_CANCEL_FLAG)
+			return -ECANCELED;
+
+		if (!req->cqe.res) {
+			struct poll_table_struct pt = { ._key = req->apoll_events };
+			req->cqe.res = vfs_poll(req->file, &pt) & req->apoll_events;
+		}
+
+		if ((unlikely(!req->cqe.res)))
+			continue;
+		if (req->apoll_events & EPOLLONESHOT)
+			return 0;
+
+		/* multishot, just fill a CQE and proceed */
+		if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
+			__poll_t mask = mangle_poll(req->cqe.res &
+						    req->apoll_events);
+			bool filled;
+
+			spin_lock(&ctx->completion_lock);
+			filled = io_fill_cqe_aux(ctx, req->cqe.user_data,
+						 mask, IORING_CQE_F_MORE);
+			io_commit_cqring(ctx);
+			spin_unlock(&ctx->completion_lock);
+			if (filled) {
+				io_cqring_ev_posted(ctx);
+				continue;
+			}
+			return -ECANCELED;
+		}
+
+		ret = io_poll_issue(req, locked);
+		if (ret)
+			return ret;
+
+		/*
+		 * Release all references, retry if someone tried to restart
+		 * task_work while we were executing it.
+		 */
+	} while (atomic_sub_return(v & IO_POLL_REF_MASK, &req->poll_refs));
+
+	return 1;
+}
+
+static void io_poll_task_func(struct io_kiocb *req, bool *locked)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	int ret;
+
+	ret = io_poll_check_events(req, locked);
+	if (ret > 0)
+		return;
+
+	if (!ret) {
+		struct io_poll *poll = io_kiocb_to_cmd(req);
+
+		req->cqe.res = mangle_poll(req->cqe.res & poll->events);
+	} else {
+		req->cqe.res = ret;
+		req_set_fail(req);
+	}
+
+	io_poll_remove_entries(req);
+	spin_lock(&ctx->completion_lock);
+	hash_del(&req->hash_node);
+	req->cqe.flags = 0;
+	__io_req_complete_post(req);
+	io_commit_cqring(ctx);
+	spin_unlock(&ctx->completion_lock);
+	io_cqring_ev_posted(ctx);
+}
+
+static void io_apoll_task_func(struct io_kiocb *req, bool *locked)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	int ret;
+
+	ret = io_poll_check_events(req, locked);
+	if (ret > 0)
+		return;
+
+	io_poll_remove_entries(req);
+	spin_lock(&ctx->completion_lock);
+	hash_del(&req->hash_node);
+	spin_unlock(&ctx->completion_lock);
+
+	if (!ret)
+		io_req_task_submit(req, locked);
+	else
+		io_req_complete_failed(req, ret);
+}
+
+static void __io_poll_execute(struct io_kiocb *req, int mask,
+			      __poll_t __maybe_unused events)
+{
+	io_req_set_res(req, mask, 0);
+	/*
+	 * This is useful for poll that is armed on behalf of another
+	 * request, and where the wakeup path could be on a different
+	 * CPU. We want to avoid pulling in req->apoll->events for that
+	 * case.
+	 */
+	if (req->opcode == IORING_OP_POLL_ADD)
+		req->io_task_work.func = io_poll_task_func;
+	else
+		req->io_task_work.func = io_apoll_task_func;
+
+	trace_io_uring_task_add(req->ctx, req, req->cqe.user_data, req->opcode, mask);
+	io_req_task_work_add(req);
+}
+
+static inline void io_poll_execute(struct io_kiocb *req, int res,
+		__poll_t events)
+{
+	if (io_poll_get_ownership(req))
+		__io_poll_execute(req, res, events);
+}
+
+static void io_poll_cancel_req(struct io_kiocb *req)
+{
+	io_poll_mark_cancelled(req);
+	/* kick tw, which should complete the request */
+	io_poll_execute(req, 0, 0);
+}
+
+#define wqe_to_req(wait)	((void *)((unsigned long) (wait)->private & ~1))
+#define wqe_is_double(wait)	((unsigned long) (wait)->private & 1)
+#define IO_ASYNC_POLL_COMMON	(EPOLLONESHOT | EPOLLPRI)
+
+static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
+			void *key)
+{
+	struct io_kiocb *req = wqe_to_req(wait);
+	struct io_poll *poll = container_of(wait, struct io_poll, wait);
+	__poll_t mask = key_to_poll(key);
+
+	if (unlikely(mask & POLLFREE)) {
+		io_poll_mark_cancelled(req);
+		/* we have to kick tw in case it's not already */
+		io_poll_execute(req, 0, poll->events);
+
+		/*
+		 * If the waitqueue is being freed early but someone is already
+		 * holds ownership over it, we have to tear down the request as
+		 * best we can. That means immediately removing the request from
+		 * its waitqueue and preventing all further accesses to the
+		 * waitqueue via the request.
+		 */
+		list_del_init(&poll->wait.entry);
+
+		/*
+		 * Careful: this *must* be the last step, since as soon
+		 * as req->head is NULL'ed out, the request can be
+		 * completed and freed, since aio_poll_complete_work()
+		 * will no longer need to take the waitqueue lock.
+		 */
+		smp_store_release(&poll->head, NULL);
+		return 1;
+	}
+
+	/* for instances that support it check for an event match first */
+	if (mask && !(mask & (poll->events & ~IO_ASYNC_POLL_COMMON)))
+		return 0;
+
+	if (io_poll_get_ownership(req)) {
+		/* optional, saves extra locking for removal in tw handler */
+		if (mask && poll->events & EPOLLONESHOT) {
+			list_del_init(&poll->wait.entry);
+			poll->head = NULL;
+			if (wqe_is_double(wait))
+				req->flags &= ~REQ_F_DOUBLE_POLL;
+			else
+				req->flags &= ~REQ_F_SINGLE_POLL;
+		}
+		__io_poll_execute(req, mask, poll->events);
+	}
+	return 1;
+}
+
+static void __io_queue_proc(struct io_poll *poll, struct io_poll_table *pt,
+			    struct wait_queue_head *head,
+			    struct io_poll **poll_ptr)
+{
+	struct io_kiocb *req = pt->req;
+	unsigned long wqe_private = (unsigned long) req;
+
+	/*
+	 * The file being polled uses multiple waitqueues for poll handling
+	 * (e.g. one for read, one for write). Setup a separate io_poll
+	 * if this happens.
+	 */
+	if (unlikely(pt->nr_entries)) {
+		struct io_poll *first = poll;
+
+		/* double add on the same waitqueue head, ignore */
+		if (first->head == head)
+			return;
+		/* already have a 2nd entry, fail a third attempt */
+		if (*poll_ptr) {
+			if ((*poll_ptr)->head == head)
+				return;
+			pt->error = -EINVAL;
+			return;
+		}
+
+		poll = kmalloc(sizeof(*poll), GFP_ATOMIC);
+		if (!poll) {
+			pt->error = -ENOMEM;
+			return;
+		}
+		/* mark as double wq entry */
+		wqe_private |= 1;
+		req->flags |= REQ_F_DOUBLE_POLL;
+		io_init_poll_iocb(poll, first->events, first->wait.func);
+		*poll_ptr = poll;
+		if (req->opcode == IORING_OP_POLL_ADD)
+			req->flags |= REQ_F_ASYNC_DATA;
+	}
+
+	req->flags |= REQ_F_SINGLE_POLL;
+	pt->nr_entries++;
+	poll->head = head;
+	poll->wait.private = (void *) wqe_private;
+
+	if (poll->events & EPOLLEXCLUSIVE)
+		add_wait_queue_exclusive(head, &poll->wait);
+	else
+		add_wait_queue(head, &poll->wait);
+}
+
+static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head,
+			       struct poll_table_struct *p)
+{
+	struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
+	struct io_poll *poll = io_kiocb_to_cmd(pt->req);
+
+	__io_queue_proc(poll, pt, head,
+			(struct io_poll **) &pt->req->async_data);
+}
+
+static int __io_arm_poll_handler(struct io_kiocb *req,
+				 struct io_poll *poll,
+				 struct io_poll_table *ipt, __poll_t mask)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	int v;
+
+	INIT_HLIST_NODE(&req->hash_node);
+	req->work.cancel_seq = atomic_read(&ctx->cancel_seq);
+	io_init_poll_iocb(poll, mask, io_poll_wake);
+	poll->file = req->file;
+
+	req->apoll_events = poll->events;
+
+	ipt->pt._key = mask;
+	ipt->req = req;
+	ipt->error = 0;
+	ipt->nr_entries = 0;
+
+	/*
+	 * Take the ownership to delay any tw execution up until we're done
+	 * with poll arming. see io_poll_get_ownership().
+	 */
+	atomic_set(&req->poll_refs, 1);
+	mask = vfs_poll(req->file, &ipt->pt) & poll->events;
+
+	if (mask && (poll->events & EPOLLONESHOT)) {
+		io_poll_remove_entries(req);
+		/* no one else has access to the req, forget about the ref */
+		return mask;
+	}
+	if (!mask && unlikely(ipt->error || !ipt->nr_entries)) {
+		io_poll_remove_entries(req);
+		if (!ipt->error)
+			ipt->error = -EINVAL;
+		return 0;
+	}
+
+	spin_lock(&ctx->completion_lock);
+	io_poll_req_insert(req);
+	spin_unlock(&ctx->completion_lock);
+
+	if (mask) {
+		/* can't multishot if failed, just queue the event we've got */
+		if (unlikely(ipt->error || !ipt->nr_entries)) {
+			poll->events |= EPOLLONESHOT;
+			req->apoll_events |= EPOLLONESHOT;
+			ipt->error = 0;
+		}
+		__io_poll_execute(req, mask, poll->events);
+		return 0;
+	}
+
+	/*
+	 * Release ownership. If someone tried to queue a tw while it was
+	 * locked, kick it off for them.
+	 */
+	v = atomic_dec_return(&req->poll_refs);
+	if (unlikely(v & IO_POLL_REF_MASK))
+		__io_poll_execute(req, 0, poll->events);
+	return 0;
+}
+
+static void io_async_queue_proc(struct file *file, struct wait_queue_head *head,
+			       struct poll_table_struct *p)
+{
+	struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
+	struct async_poll *apoll = pt->req->apoll;
+
+	__io_queue_proc(&apoll->poll, pt, head, &apoll->double_poll);
+}
+
+int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags)
+{
+	const struct io_op_def *def = &io_op_defs[req->opcode];
+	struct io_ring_ctx *ctx = req->ctx;
+	struct async_poll *apoll;
+	struct io_poll_table ipt;
+	__poll_t mask = POLLPRI | POLLERR;
+	int ret;
+
+	if (!def->pollin && !def->pollout)
+		return IO_APOLL_ABORTED;
+	if (!file_can_poll(req->file))
+		return IO_APOLL_ABORTED;
+	if ((req->flags & (REQ_F_POLLED|REQ_F_PARTIAL_IO)) == REQ_F_POLLED)
+		return IO_APOLL_ABORTED;
+	if (!(req->flags & REQ_F_APOLL_MULTISHOT))
+		mask |= EPOLLONESHOT;
+
+	if (def->pollin) {
+		mask |= EPOLLIN | EPOLLRDNORM;
+
+		/* If reading from MSG_ERRQUEUE using recvmsg, ignore POLLIN */
+		if (req->flags & REQ_F_CLEAR_POLLIN)
+			mask &= ~EPOLLIN;
+	} else {
+		mask |= EPOLLOUT | EPOLLWRNORM;
+	}
+	if (def->poll_exclusive)
+		mask |= EPOLLEXCLUSIVE;
+	if (req->flags & REQ_F_POLLED) {
+		apoll = req->apoll;
+		kfree(apoll->double_poll);
+	} else if (!(issue_flags & IO_URING_F_UNLOCKED) &&
+		   !list_empty(&ctx->apoll_cache)) {
+		apoll = list_first_entry(&ctx->apoll_cache, struct async_poll,
+						poll.wait.entry);
+		list_del_init(&apoll->poll.wait.entry);
+	} else {
+		apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
+		if (unlikely(!apoll))
+			return IO_APOLL_ABORTED;
+	}
+	apoll->double_poll = NULL;
+	req->apoll = apoll;
+	req->flags |= REQ_F_POLLED;
+	ipt.pt._qproc = io_async_queue_proc;
+
+	io_kbuf_recycle(req, issue_flags);
+
+	ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask);
+	if (ret || ipt.error)
+		return ret ? IO_APOLL_READY : IO_APOLL_ABORTED;
+
+	trace_io_uring_poll_arm(ctx, req, req->cqe.user_data, req->opcode,
+				mask, apoll->poll.events);
+	return IO_APOLL_OK;
+}
+
+/*
+ * Returns true if we found and killed one or more poll requests
+ */
+__cold bool io_poll_remove_all(struct io_ring_ctx *ctx, struct task_struct *tsk,
+			       bool cancel_all)
+{
+	struct hlist_node *tmp;
+	struct io_kiocb *req;
+	bool found = false;
+	int i;
+
+	spin_lock(&ctx->completion_lock);
+	for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
+		struct hlist_head *list;
+
+		list = &ctx->cancel_hash[i];
+		hlist_for_each_entry_safe(req, tmp, list, hash_node) {
+			if (io_match_task_safe(req, tsk, cancel_all)) {
+				hlist_del_init(&req->hash_node);
+				io_poll_cancel_req(req);
+				found = true;
+			}
+		}
+	}
+	spin_unlock(&ctx->completion_lock);
+	return found;
+}
+
+static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, bool poll_only,
+				     struct io_cancel_data *cd)
+	__must_hold(&ctx->completion_lock)
+{
+	struct hlist_head *list;
+	struct io_kiocb *req;
+
+	list = &ctx->cancel_hash[hash_long(cd->data, ctx->cancel_hash_bits)];
+	hlist_for_each_entry(req, list, hash_node) {
+		if (cd->data != req->cqe.user_data)
+			continue;
+		if (poll_only && req->opcode != IORING_OP_POLL_ADD)
+			continue;
+		if (cd->flags & IORING_ASYNC_CANCEL_ALL) {
+			if (cd->seq == req->work.cancel_seq)
+				continue;
+			req->work.cancel_seq = cd->seq;
+		}
+		return req;
+	}
+	return NULL;
+}
+
+static struct io_kiocb *io_poll_file_find(struct io_ring_ctx *ctx,
+					  struct io_cancel_data *cd)
+	__must_hold(&ctx->completion_lock)
+{
+	struct io_kiocb *req;
+	int i;
+
+	for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
+		struct hlist_head *list;
+
+		list = &ctx->cancel_hash[i];
+		hlist_for_each_entry(req, list, hash_node) {
+			if (!(cd->flags & IORING_ASYNC_CANCEL_ANY) &&
+			    req->file != cd->file)
+				continue;
+			if (cd->seq == req->work.cancel_seq)
+				continue;
+			req->work.cancel_seq = cd->seq;
+			return req;
+		}
+	}
+	return NULL;
+}
+
+static bool io_poll_disarm(struct io_kiocb *req)
+	__must_hold(&ctx->completion_lock)
+{
+	if (!io_poll_get_ownership(req))
+		return false;
+	io_poll_remove_entries(req);
+	hash_del(&req->hash_node);
+	return true;
+}
+
+int io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd)
+	__must_hold(&ctx->completion_lock)
+{
+	struct io_kiocb *req;
+
+	if (cd->flags & (IORING_ASYNC_CANCEL_FD|IORING_ASYNC_CANCEL_ANY))
+		req = io_poll_file_find(ctx, cd);
+	else
+		req = io_poll_find(ctx, false, cd);
+	if (!req)
+		return -ENOENT;
+	io_poll_cancel_req(req);
+	return 0;
+}
+
+static __poll_t io_poll_parse_events(const struct io_uring_sqe *sqe,
+				     unsigned int flags)
+{
+	u32 events;
+
+	events = READ_ONCE(sqe->poll32_events);
+#ifdef __BIG_ENDIAN
+	events = swahw32(events);
+#endif
+	if (!(flags & IORING_POLL_ADD_MULTI))
+		events |= EPOLLONESHOT;
+	return demangle_poll(events) | (events & (EPOLLEXCLUSIVE|EPOLLONESHOT));
+}
+
+int io_poll_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_poll_update *upd = io_kiocb_to_cmd(req);
+	u32 flags;
+
+	if (sqe->buf_index || sqe->splice_fd_in)
+		return -EINVAL;
+	flags = READ_ONCE(sqe->len);
+	if (flags & ~(IORING_POLL_UPDATE_EVENTS | IORING_POLL_UPDATE_USER_DATA |
+		      IORING_POLL_ADD_MULTI))
+		return -EINVAL;
+	/* meaningless without update */
+	if (flags == IORING_POLL_ADD_MULTI)
+		return -EINVAL;
+
+	upd->old_user_data = READ_ONCE(sqe->addr);
+	upd->update_events = flags & IORING_POLL_UPDATE_EVENTS;
+	upd->update_user_data = flags & IORING_POLL_UPDATE_USER_DATA;
+
+	upd->new_user_data = READ_ONCE(sqe->off);
+	if (!upd->update_user_data && upd->new_user_data)
+		return -EINVAL;
+	if (upd->update_events)
+		upd->events = io_poll_parse_events(sqe, flags);
+	else if (sqe->poll32_events)
+		return -EINVAL;
+
+	return 0;
+}
+
+int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+{
+	struct io_poll *poll = io_kiocb_to_cmd(req);
+	u32 flags;
+
+	if (sqe->buf_index || sqe->off || sqe->addr)
+		return -EINVAL;
+	flags = READ_ONCE(sqe->len);
+	if (flags & ~IORING_POLL_ADD_MULTI)
+		return -EINVAL;
+	if ((flags & IORING_POLL_ADD_MULTI) && (req->flags & REQ_F_CQE_SKIP))
+		return -EINVAL;
+
+	io_req_set_refcount(req);
+	poll->events = io_poll_parse_events(sqe, flags);
+	return 0;
+}
+
+int io_poll_add(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_poll *poll = io_kiocb_to_cmd(req);
+	struct io_poll_table ipt;
+	int ret;
+
+	ipt.pt._qproc = io_poll_queue_proc;
+
+	ret = __io_arm_poll_handler(req, poll, &ipt, poll->events);
+	if (ret) {
+		io_req_set_res(req, ret, 0);
+		return IOU_OK;
+	}
+	if (ipt.error) {
+		req_set_fail(req);
+		return ipt.error;
+	}
+
+	return IOU_ISSUE_SKIP_COMPLETE;
+}
+
+int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_poll_update *poll_update = io_kiocb_to_cmd(req);
+	struct io_cancel_data cd = { .data = poll_update->old_user_data, };
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_kiocb *preq;
+	int ret2, ret = 0;
+	bool locked;
+
+	spin_lock(&ctx->completion_lock);
+	preq = io_poll_find(ctx, true, &cd);
+	if (!preq || !io_poll_disarm(preq)) {
+		spin_unlock(&ctx->completion_lock);
+		ret = preq ? -EALREADY : -ENOENT;
+		goto out;
+	}
+	spin_unlock(&ctx->completion_lock);
+
+	if (poll_update->update_events || poll_update->update_user_data) {
+		/* only mask one event flags, keep behavior flags */
+		if (poll_update->update_events) {
+			struct io_poll *poll = io_kiocb_to_cmd(preq);
+
+			poll->events &= ~0xffff;
+			poll->events |= poll_update->events & 0xffff;
+			poll->events |= IO_POLL_UNMASK;
+		}
+		if (poll_update->update_user_data)
+			preq->cqe.user_data = poll_update->new_user_data;
+
+		ret2 = io_poll_add(preq, issue_flags);
+		/* successfully updated, don't complete poll request */
+		if (!ret2 || ret2 == -EIOCBQUEUED)
+			goto out;
+	}
+
+	req_set_fail(preq);
+	io_req_set_res(preq, -ECANCELED, 0);
+	locked = !(issue_flags & IO_URING_F_UNLOCKED);
+	io_req_task_complete(preq, &locked);
+out:
+	if (ret < 0) {
+		req_set_fail(req);
+		return ret;
+	}
+	/* complete update request, we're done with it */
+	io_req_set_res(req, ret, 0);
+	return IOU_OK;
+}
diff --git a/io_uring/poll.h b/io_uring/poll.h
new file mode 100644
index 000000000000..cc75c1567a84
--- /dev/null
+++ b/io_uring/poll.h
@@ -0,0 +1,30 @@
+// 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);