io_uring: move read/write related opcodes to its own file

Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 9 insertions, 1230 deletions

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index c0f1f79933ac..0af61a6c29cf 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -43,7 +43,6 @@
 #include <linux/init.h>
 #include <linux/errno.h>
 #include <linux/syscalls.h>
-#include <linux/compat.h>
 #include <net/compat.h>
 #include <linux/refcount.h>
 #include <linux/uio.h>
@@ -57,7 +56,6 @@
 #include <linux/mman.h>
 #include <linux/percpu.h>
 #include <linux/slab.h>
-#include <linux/blk-mq.h>
 #include <linux/bvec.h>
 #include <linux/net.h>
 #include <net/sock.h>
@@ -67,13 +65,10 @@
 #include <linux/sched/mm.h>
 #include <linux/uaccess.h>
 #include <linux/nospec.h>
-#include <linux/sizes.h>
 #include <linux/highmem.h>
 #include <linux/fsnotify.h>
 #include <linux/fadvise.h>
-#include <linux/eventpoll.h>
 #include <linux/task_work.h>
-#include <linux/pagemap.h>
 #include <linux/io_uring.h>
 #include <linux/audit.h>
 #include <linux/security.h>
@@ -110,6 +105,7 @@
 #include "timeout.h"
 #include "poll.h"
 #include "cancel.h"
+#include "rw.h"
 
 #define IORING_MAX_ENTRIES	32768
 #define IORING_MAX_CQ_ENTRIES	(2 * IORING_MAX_ENTRIES)
@@ -136,31 +132,6 @@
 #define IO_REQ_CACHE_SIZE		32
 #define IO_REQ_ALLOC_BATCH		8
 
-/*
- * First field must be the file pointer in all the
- * iocb unions! See also 'struct kiocb' in <linux/fs.h>
- */
-struct io_rw {
-	/* NOTE: kiocb has the file as the first member, so don't do it here */
-	struct kiocb			kiocb;
-	u64				addr;
-	u32				len;
-	rwf_t				flags;
-};
-
-struct io_rw_state {
-	struct iov_iter			iter;
-	struct iov_iter_state		iter_state;
-	struct iovec			fast_iov[UIO_FASTIOV];
-};
-
-struct io_async_rw {
-	struct io_rw_state		s;
-	const struct iovec		*free_iovec;
-	size_t				bytes_done;
-	struct wait_page_queue		wpq;
-};
-
 enum {
 	IO_CHECK_CQ_OVERFLOW_BIT,
 	IO_CHECK_CQ_DROPPED_BIT,
@@ -184,9 +155,7 @@ static void io_dismantle_req(struct io_kiocb *req);
 static void io_clean_op(struct io_kiocb *req);
 static void io_queue_sqe(struct io_kiocb *req);
 
-static void io_req_task_queue(struct io_kiocb *req);
 static void __io_submit_flush_completions(struct io_ring_ctx *ctx);
-static int io_req_prep_async(struct io_kiocb *req);
 
 static void io_eventfd_signal(struct io_ring_ctx *ctx);
 
@@ -393,11 +362,6 @@ static bool req_need_defer(struct io_kiocb *req, u32 seq)
 	return false;
 }
 
-static inline bool io_req_ffs_set(struct io_kiocb *req)
-{
-	return req->flags & REQ_F_FIXED_FILE;
-}
-
 static inline void io_req_track_inflight(struct io_kiocb *req)
 {
 	if (!(req->flags & REQ_F_INFLIGHT)) {
@@ -489,7 +453,7 @@ static inline void io_req_add_compl_list(struct io_kiocb *req)
 	wq_list_add_tail(&req->comp_list, &state->compl_reqs);
 }
 
-static void io_queue_iowq(struct io_kiocb *req, bool *dont_use)
+void io_queue_iowq(struct io_kiocb *req, bool *dont_use)
 {
 	struct io_kiocb *link = io_prep_linked_timeout(req);
 	struct io_uring_task *tctx = req->task->io_uring;
@@ -532,7 +496,7 @@ static __cold void io_queue_deferred(struct io_ring_ctx *ctx)
 	}
 }
 
-static void __io_commit_cqring_flush(struct io_ring_ctx *ctx)
+void __io_commit_cqring_flush(struct io_ring_ctx *ctx)
 {
 	if (ctx->off_timeout_used || ctx->drain_active) {
 		spin_lock(&ctx->completion_lock);
@@ -547,60 +511,6 @@ static void __io_commit_cqring_flush(struct io_ring_ctx *ctx)
 		io_eventfd_signal(ctx);
 }
 
-static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx)
-{
-	return ctx->cached_cq_tail - READ_ONCE(ctx->rings->cq.head);
-}
-
-/*
- * writes to the cq entry need to come after reading head; the
- * control dependency is enough as we're using WRITE_ONCE to
- * fill the cq entry
- */
-static noinline struct io_uring_cqe *__io_get_cqe(struct io_ring_ctx *ctx)
-{
-	struct io_rings *rings = ctx->rings;
-	unsigned int off = ctx->cached_cq_tail & (ctx->cq_entries - 1);
-	unsigned int shift = 0;
-	unsigned int free, queued, len;
-
-	if (ctx->flags & IORING_SETUP_CQE32)
-		shift = 1;
-
-	/* userspace may cheat modifying the tail, be safe and do min */
-	queued = min(__io_cqring_events(ctx), ctx->cq_entries);
-	free = ctx->cq_entries - queued;
-	/* we need a contiguous range, limit based on the current array offset */
-	len = min(free, ctx->cq_entries - off);
-	if (!len)
-		return NULL;
-
-	ctx->cached_cq_tail++;
-	ctx->cqe_cached = &rings->cqes[off];
-	ctx->cqe_sentinel = ctx->cqe_cached + len;
-	ctx->cqe_cached++;
-	return &rings->cqes[off << shift];
-}
-
-static inline struct io_uring_cqe *io_get_cqe(struct io_ring_ctx *ctx)
-{
-	if (likely(ctx->cqe_cached < ctx->cqe_sentinel)) {
-		struct io_uring_cqe *cqe = ctx->cqe_cached;
-
-		if (ctx->flags & IORING_SETUP_CQE32) {
-			unsigned int off = ctx->cqe_cached - ctx->rings->cqes;
-
-			cqe += off;
-		}
-
-		ctx->cached_cq_tail++;
-		ctx->cqe_cached++;
-		return cqe;
-	}
-
-	return __io_get_cqe(ctx);
-}
-
 static void io_eventfd_signal(struct io_ring_ctx *ctx)
 {
 	struct io_ev_fd *ev_fd;
@@ -628,17 +538,6 @@ out:
 	rcu_read_unlock();
 }
 
-static inline void io_cqring_wake(struct io_ring_ctx *ctx)
-{
-	/*
-	 * wake_up_all() may seem excessive, but io_wake_function() and
-	 * io_should_wake() handle the termination of the loop and only
-	 * wake as many waiters as we need to.
-	 */
-	if (wq_has_sleeper(&ctx->cq_wait))
-		wake_up_all(&ctx->cq_wait);
-}
-
 /*
  * This should only get called when at least one event has been posted.
  * Some applications rely on the eventfd notification count only changing
@@ -655,16 +554,6 @@ void io_cqring_ev_posted(struct io_ring_ctx *ctx)
 	io_cqring_wake(ctx);
 }
 
-static void io_cqring_ev_posted_iopoll(struct io_ring_ctx *ctx)
-{
-	if (unlikely(ctx->off_timeout_used || ctx->drain_active ||
-		     ctx->has_evfd))
-		__io_commit_cqring_flush(ctx);
-
-	if (ctx->flags & IORING_SETUP_SQPOLL)
-		io_cqring_wake(ctx);
-}
-
 /* Returns true if there are no backlogged entries after the flush */
 static bool __io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force)
 {
@@ -775,9 +664,8 @@ static __cold void io_uring_drop_tctx_refs(struct task_struct *task)
 	}
 }
 
-static bool io_cqring_event_overflow(struct io_ring_ctx *ctx, u64 user_data,
-				     s32 res, u32 cflags, u64 extra1,
-				     u64 extra2)
+bool io_cqring_event_overflow(struct io_ring_ctx *ctx, u64 user_data, s32 res,
+			      u32 cflags, u64 extra1, u64 extra2)
 {
 	struct io_overflow_cqe *ocqe;
 	size_t ocq_size = sizeof(struct io_overflow_cqe);
@@ -814,59 +702,6 @@ static bool io_cqring_event_overflow(struct io_ring_ctx *ctx, u64 user_data,
 	return true;
 }
 
-static inline bool __io_fill_cqe_req(struct io_ring_ctx *ctx,
-				     struct io_kiocb *req)
-{
-	struct io_uring_cqe *cqe;
-
-	if (!(ctx->flags & IORING_SETUP_CQE32)) {
-		trace_io_uring_complete(req->ctx, req, req->cqe.user_data,
-					req->cqe.res, req->cqe.flags, 0, 0);
-
-		/*
-		 * If we can't get a cq entry, userspace overflowed the
-		 * submission (by quite a lot). Increment the overflow count in
-		 * the ring.
-		 */
-		cqe = io_get_cqe(ctx);
-		if (likely(cqe)) {
-			memcpy(cqe, &req->cqe, sizeof(*cqe));
-			return true;
-		}
-
-		return io_cqring_event_overflow(ctx, req->cqe.user_data,
-						req->cqe.res, req->cqe.flags,
-						0, 0);
-	} else {
-		u64 extra1 = 0, extra2 = 0;
-
-		if (req->flags & REQ_F_CQE32_INIT) {
-			extra1 = req->extra1;
-			extra2 = req->extra2;
-		}
-
-		trace_io_uring_complete(req->ctx, req, req->cqe.user_data,
-					req->cqe.res, req->cqe.flags, extra1, extra2);
-
-		/*
-		 * If we can't get a cq entry, userspace overflowed the
-		 * submission (by quite a lot). Increment the overflow count in
-		 * the ring.
-		 */
-		cqe = io_get_cqe(ctx);
-		if (likely(cqe)) {
-			memcpy(cqe, &req->cqe, sizeof(struct io_uring_cqe));
-			WRITE_ONCE(cqe->big_cqe[0], extra1);
-			WRITE_ONCE(cqe->big_cqe[1], extra2);
-			return true;
-		}
-
-		return io_cqring_event_overflow(ctx, req->cqe.user_data,
-				req->cqe.res, req->cqe.flags,
-				extra1, extra2);
-	}
-}
-
 bool io_fill_cqe_aux(struct io_ring_ctx *ctx, u64 user_data, s32 res,
 		     u32 cflags)
 {
@@ -1269,7 +1104,7 @@ void io_req_task_work_add(struct io_kiocb *req)
 	__io_req_task_work_add(req, tctx, &tctx->task_list);
 }
 
-static void io_req_task_prio_work_add(struct io_kiocb *req)
+void io_req_task_prio_work_add(struct io_kiocb *req)
 {
 	struct io_uring_task *tctx = req->task->io_uring;
 
@@ -1315,18 +1150,12 @@ void io_req_task_queue_fail(struct io_kiocb *req, int ret)
 	io_req_task_work_add(req);
 }
 
-static void io_req_task_queue(struct io_kiocb *req)
+void io_req_task_queue(struct io_kiocb *req)
 {
 	req->io_task_work.func = io_req_task_submit;
 	io_req_task_work_add(req);
 }
 
-static void io_req_task_queue_reissue(struct io_kiocb *req)
-{
-	req->io_task_work.func = io_queue_iowq;
-	io_req_task_work_add(req);
-}
-
 void io_queue_next(struct io_kiocb *req)
 {
 	struct io_kiocb *nxt = io_req_find_next(req);
@@ -1335,8 +1164,7 @@ void io_queue_next(struct io_kiocb *req)
 		io_req_task_queue(nxt);
 }
 
-static void io_free_batch_list(struct io_ring_ctx *ctx,
-				struct io_wq_work_node *node)
+void io_free_batch_list(struct io_ring_ctx *ctx, struct io_wq_work_node *node)
 	__must_hold(&ctx->uring_lock)
 {
 	struct task_struct *task = NULL;
@@ -1435,76 +1263,6 @@ static unsigned io_cqring_events(struct io_ring_ctx *ctx)
 	return __io_cqring_events(ctx);
 }
 
-int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin)
-{
-	struct io_wq_work_node *pos, *start, *prev;
-	unsigned int poll_flags = BLK_POLL_NOSLEEP;
-	DEFINE_IO_COMP_BATCH(iob);
-	int nr_events = 0;
-
-	/*
-	 * Only spin for completions if we don't have multiple devices hanging
-	 * off our complete list.
-	 */
-	if (ctx->poll_multi_queue || force_nonspin)
-		poll_flags |= BLK_POLL_ONESHOT;
-
-	wq_list_for_each(pos, start, &ctx->iopoll_list) {
-		struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list);
-		struct io_rw *rw = io_kiocb_to_cmd(req);
-		int ret;
-
-		/*
-		 * Move completed and retryable entries to our local lists.
-		 * If we find a request that requires polling, break out
-		 * and complete those lists first, if we have entries there.
-		 */
-		if (READ_ONCE(req->iopoll_completed))
-			break;
-
-		ret = rw->kiocb.ki_filp->f_op->iopoll(&rw->kiocb, &iob, poll_flags);
-		if (unlikely(ret < 0))
-			return ret;
-		else if (ret)
-			poll_flags |= BLK_POLL_ONESHOT;
-
-		/* iopoll may have completed current req */
-		if (!rq_list_empty(iob.req_list) ||
-		    READ_ONCE(req->iopoll_completed))
-			break;
-	}
-
-	if (!rq_list_empty(iob.req_list))
-		iob.complete(&iob);
-	else if (!pos)
-		return 0;
-
-	prev = start;
-	wq_list_for_each_resume(pos, prev) {
-		struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list);
-
-		/* order with io_complete_rw_iopoll(), e.g. ->result updates */
-		if (!smp_load_acquire(&req->iopoll_completed))
-			break;
-		nr_events++;
-		if (unlikely(req->flags & REQ_F_CQE_SKIP))
-			continue;
-
-		req->cqe.flags = io_put_kbuf(req, 0);
-		__io_fill_cqe_req(req->ctx, req);
-	}
-
-	if (unlikely(!nr_events))
-		return 0;
-
-	io_commit_cqring(ctx);
-	io_cqring_ev_posted_iopoll(ctx);
-	pos = start ? start->next : ctx->iopoll_list.first;
-	wq_list_cut(&ctx->iopoll_list, prev, start);
-	io_free_batch_list(ctx, pos);
-	return nr_events;
-}
-
 /*
  * We can't just wait for polled events to come to us, we have to actively
  * find and complete them.
@@ -1589,90 +1347,6 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
 
 	return ret;
 }
-
-static void kiocb_end_write(struct io_kiocb *req)
-{
-	/*
-	 * Tell lockdep we inherited freeze protection from submission
-	 * thread.
-	 */
-	if (req->flags & REQ_F_ISREG) {
-		struct super_block *sb = file_inode(req->file)->i_sb;
-
-		__sb_writers_acquired(sb, SB_FREEZE_WRITE);
-		sb_end_write(sb);
-	}
-}
-
-#ifdef CONFIG_BLOCK
-static bool io_resubmit_prep(struct io_kiocb *req)
-{
-	struct io_async_rw *io = req->async_data;
-
-	if (!req_has_async_data(req))
-		return !io_req_prep_async(req);
-	iov_iter_restore(&io->s.iter, &io->s.iter_state);
-	return true;
-}
-
-static bool io_rw_should_reissue(struct io_kiocb *req)
-{
-	umode_t mode = file_inode(req->file)->i_mode;
-	struct io_ring_ctx *ctx = req->ctx;
-
-	if (!S_ISBLK(mode) && !S_ISREG(mode))
-		return false;
-	if ((req->flags & REQ_F_NOWAIT) || (io_wq_current_is_worker() &&
-	    !(ctx->flags & IORING_SETUP_IOPOLL)))
-		return false;
-	/*
-	 * If ref is dying, we might be running poll reap from the exit work.
-	 * Don't attempt to reissue from that path, just let it fail with
-	 * -EAGAIN.
-	 */
-	if (percpu_ref_is_dying(&ctx->refs))
-		return false;
-	/*
-	 * Play it safe and assume not safe to re-import and reissue if we're
-	 * not in the original thread group (or in task context).
-	 */
-	if (!same_thread_group(req->task, current) || !in_task())
-		return false;
-	return true;
-}
-#else
-static bool io_resubmit_prep(struct io_kiocb *req)
-{
-	return false;
-}
-static bool io_rw_should_reissue(struct io_kiocb *req)
-{
-	return false;
-}
-#endif
-
-static bool __io_complete_rw_common(struct io_kiocb *req, long res)
-{
-	struct io_rw *rw = io_kiocb_to_cmd(req);
-
-	if (rw->kiocb.ki_flags & IOCB_WRITE) {
-		kiocb_end_write(req);
-		fsnotify_modify(req->file);
-	} else {
-		fsnotify_access(req->file);
-	}
-	if (unlikely(res != req->cqe.res)) {
-		if ((res == -EAGAIN || res == -EOPNOTSUPP) &&
-		    io_rw_should_reissue(req)) {
-			req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO;
-			return true;
-		}
-		req_set_fail(req);
-		req->cqe.res = res;
-	}
-	return false;
-}
-
 inline void io_req_task_complete(struct io_kiocb *req, bool *locked)
 {
 	if (*locked) {
@@ -1685,46 +1359,6 @@ inline void io_req_task_complete(struct io_kiocb *req, bool *locked)
 	}
 }
 
-static void __io_complete_rw(struct io_kiocb *req, long res,
-			     unsigned int issue_flags)
-{
-	if (__io_complete_rw_common(req, res))
-		return;
-	io_req_set_res(req, req->cqe.res, io_put_kbuf(req, issue_flags));
-	__io_req_complete(req, issue_flags);
-}
-
-static void io_complete_rw(struct kiocb *kiocb, long res)
-{
-	struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb);
-	struct io_kiocb *req = cmd_to_io_kiocb(rw);
-
-	if (__io_complete_rw_common(req, res))
-		return;
-	io_req_set_res(req, res, 0);
-	req->io_task_work.func = io_req_task_complete;
-	io_req_task_prio_work_add(req);
-}
-
-static void io_complete_rw_iopoll(struct kiocb *kiocb, long res)
-{
-	struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb);
-	struct io_kiocb *req = cmd_to_io_kiocb(rw);
-
-	if (kiocb->ki_flags & IOCB_WRITE)
-		kiocb_end_write(req);
-	if (unlikely(res != req->cqe.res)) {
-		if (res == -EAGAIN && io_rw_should_reissue(req)) {
-			req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO;
-			return;
-		}
-		req->cqe.res = res;
-	}
-
-	/* order with io_iopoll_complete() checking ->iopoll_completed */
-	smp_store_release(&req->iopoll_completed, 1);
-}
-
 /*
  * After the iocb has been issued, it's safe to be found on the poll list.
  * Adding the kiocb to the list AFTER submission ensures that we don't
@@ -1833,426 +1467,6 @@ unsigned int io_file_get_flags(struct file *file)
 	return res;
 }
 
-static inline bool io_file_supports_nowait(struct io_kiocb *req)
-{
-	return req->flags & REQ_F_SUPPORT_NOWAIT;
-}
-
-static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
-{
-	struct io_rw *rw = io_kiocb_to_cmd(req);
-	unsigned ioprio;
-	int ret;
-
-	rw->kiocb.ki_pos = READ_ONCE(sqe->off);
-	/* used for fixed read/write too - just read unconditionally */
-	req->buf_index = READ_ONCE(sqe->buf_index);
-
-	if (req->opcode == IORING_OP_READ_FIXED ||
-	    req->opcode == IORING_OP_WRITE_FIXED) {
-		struct io_ring_ctx *ctx = req->ctx;
-		u16 index;
-
-		if (unlikely(req->buf_index >= ctx->nr_user_bufs))
-			return -EFAULT;
-		index = array_index_nospec(req->buf_index, ctx->nr_user_bufs);
-		req->imu = ctx->user_bufs[index];
-		io_req_set_rsrc_node(req, ctx, 0);
-	}
-
-	ioprio = READ_ONCE(sqe->ioprio);
-	if (ioprio) {
-		ret = ioprio_check_cap(ioprio);
-		if (ret)
-			return ret;
-
-		rw->kiocb.ki_ioprio = ioprio;
-	} else {
-		rw->kiocb.ki_ioprio = get_current_ioprio();
-	}
-
-	rw->addr = READ_ONCE(sqe->addr);
-	rw->len = READ_ONCE(sqe->len);
-	rw->flags = READ_ONCE(sqe->rw_flags);
-	return 0;
-}
-
-static void io_readv_writev_cleanup(struct io_kiocb *req)
-{
-	struct io_async_rw *io = req->async_data;
-
-	kfree(io->free_iovec);
-}
-
-static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
-{
-	switch (ret) {
-	case -EIOCBQUEUED:
-		break;
-	case -ERESTARTSYS:
-	case -ERESTARTNOINTR:
-	case -ERESTARTNOHAND:
-	case -ERESTART_RESTARTBLOCK:
-		/*
-		 * We can't just restart the syscall, since previously
-		 * submitted sqes may already be in progress. Just fail this
-		 * IO with EINTR.
-		 */
-		ret = -EINTR;
-		fallthrough;
-	default:
-		kiocb->ki_complete(kiocb, ret);
-	}
-}
-
-static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req)
-{
-	struct io_rw *rw = io_kiocb_to_cmd(req);
-
-	if (rw->kiocb.ki_pos != -1)
-		return &rw->kiocb.ki_pos;
-
-	if (!(req->file->f_mode & FMODE_STREAM)) {
-		req->flags |= REQ_F_CUR_POS;
-		rw->kiocb.ki_pos = req->file->f_pos;
-		return &rw->kiocb.ki_pos;
-	}
-
-	rw->kiocb.ki_pos = 0;
-	return NULL;
-}
-
-static void kiocb_done(struct io_kiocb *req, ssize_t ret,
-		       unsigned int issue_flags)
-{
-	struct io_async_rw *io = req->async_data;
-	struct io_rw *rw = io_kiocb_to_cmd(req);
-
-	/* add previously done IO, if any */
-	if (req_has_async_data(req) && io->bytes_done > 0) {
-		if (ret < 0)
-			ret = io->bytes_done;
-		else
-			ret += io->bytes_done;
-	}
-
-	if (req->flags & REQ_F_CUR_POS)
-		req->file->f_pos = rw->kiocb.ki_pos;
-	if (ret >= 0 && (rw->kiocb.ki_complete == io_complete_rw))
-		__io_complete_rw(req, ret, issue_flags);
-	else
-		io_rw_done(&rw->kiocb, ret);
-
-	if (req->flags & REQ_F_REISSUE) {
-		req->flags &= ~REQ_F_REISSUE;
-		if (io_resubmit_prep(req))
-			io_req_task_queue_reissue(req);
-		else
-			io_req_task_queue_fail(req, ret);
-	}
-}
-
-static int __io_import_fixed(struct io_kiocb *req, int ddir,
-			     struct iov_iter *iter, struct io_mapped_ubuf *imu)
-{
-	struct io_rw *rw = io_kiocb_to_cmd(req);
-	size_t len = rw->len;
-	u64 buf_end, buf_addr = rw->addr;
-	size_t offset;
-
-	if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
-		return -EFAULT;
-	/* not inside the mapped region */
-	if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end))
-		return -EFAULT;
-
-	/*
-	 * May not be a start of buffer, set size appropriately
-	 * and advance us to the beginning.
-	 */
-	offset = buf_addr - imu->ubuf;
-	iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len);
-
-	if (offset) {
-		/*
-		 * Don't use iov_iter_advance() here, as it's really slow for
-		 * using the latter parts of a big fixed buffer - it iterates
-		 * over each segment manually. We can cheat a bit here, because
-		 * we know that:
-		 *
-		 * 1) it's a BVEC iter, we set it up
-		 * 2) all bvecs are PAGE_SIZE in size, except potentially the
-		 *    first and last bvec
-		 *
-		 * So just find our index, and adjust the iterator afterwards.
-		 * If the offset is within the first bvec (or the whole first
-		 * bvec, just use iov_iter_advance(). This makes it easier
-		 * since we can just skip the first segment, which may not
-		 * be PAGE_SIZE aligned.
-		 */
-		const struct bio_vec *bvec = imu->bvec;
-
-		if (offset <= bvec->bv_len) {
-			iov_iter_advance(iter, offset);
-		} else {
-			unsigned long seg_skip;
-
-			/* skip first vec */
-			offset -= bvec->bv_len;
-			seg_skip = 1 + (offset >> PAGE_SHIFT);
-
-			iter->bvec = bvec + seg_skip;
-			iter->nr_segs -= seg_skip;
-			iter->count -= bvec->bv_len + offset;
-			iter->iov_offset = offset & ~PAGE_MASK;
-		}
-	}
-
-	return 0;
-}
-
-static int io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter,
-			   unsigned int issue_flags)
-{
-	if (WARN_ON_ONCE(!req->imu))
-		return -EFAULT;
-	return __io_import_fixed(req, rw, iter, req->imu);
-}
-
-#ifdef CONFIG_COMPAT
-static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov,
-				unsigned int issue_flags)
-{
-	struct io_rw *rw = io_kiocb_to_cmd(req);
-	struct compat_iovec __user *uiov;
-	compat_ssize_t clen;
-	void __user *buf;
-	size_t len;
-
-	uiov = u64_to_user_ptr(rw->addr);
-	if (!access_ok(uiov, sizeof(*uiov)))
-		return -EFAULT;
-	if (__get_user(clen, &uiov->iov_len))
-		return -EFAULT;
-	if (clen < 0)
-		return -EINVAL;
-
-	len = clen;
-	buf = io_buffer_select(req, &len, issue_flags);
-	if (!buf)
-		return -ENOBUFS;
-	rw->addr = (unsigned long) buf;
-	iov[0].iov_base = buf;
-	rw->len = iov[0].iov_len = (compat_size_t) len;
-	return 0;
-}
-#endif
-
-static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
-				      unsigned int issue_flags)
-{
-	struct io_rw *rw = io_kiocb_to_cmd(req);
-	struct iovec __user *uiov = u64_to_user_ptr(rw->addr);
-	void __user *buf;
-	ssize_t len;
-
-	if (copy_from_user(iov, uiov, sizeof(*uiov)))
-		return -EFAULT;
-
-	len = iov[0].iov_len;
-	if (len < 0)
-		return -EINVAL;
-	buf = io_buffer_select(req, &len, issue_flags);
-	if (!buf)
-		return -ENOBUFS;
-	rw->addr = (unsigned long) buf;
-	iov[0].iov_base = buf;
-	rw->len = iov[0].iov_len = len;
-	return 0;
-}
-
-static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
-				    unsigned int issue_flags)
-{
-	struct io_rw *rw = io_kiocb_to_cmd(req);
-
-	if (req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)) {
-		iov[0].iov_base = u64_to_user_ptr(rw->addr);
-		iov[0].iov_len = rw->len;
-		return 0;
-	}
-	if (rw->len != 1)
-		return -EINVAL;
-
-#ifdef CONFIG_COMPAT
-	if (req->ctx->compat)
-		return io_compat_import(req, iov, issue_flags);
-#endif
-
-	return __io_iov_buffer_select(req, iov, issue_flags);
-}
-
-static struct iovec *__io_import_iovec(int ddir, struct io_kiocb *req,
-				       struct io_rw_state *s,
-				       unsigned int issue_flags)
-{
-	struct io_rw *rw = io_kiocb_to_cmd(req);
-	struct iov_iter *iter = &s->iter;
-	u8 opcode = req->opcode;
-	struct iovec *iovec;
-	void __user *buf;
-	size_t sqe_len;
-	ssize_t ret;
-
-	if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
-		ret = io_import_fixed(req, ddir, iter, issue_flags);
-		if (ret)
-			return ERR_PTR(ret);
-		return NULL;
-	}
-
-	buf = u64_to_user_ptr(rw->addr);
-	sqe_len = rw->len;
-
-	if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE) {
-		if (io_do_buffer_select(req)) {
-			buf = io_buffer_select(req, &sqe_len, issue_flags);
-			if (!buf)
-				return ERR_PTR(-ENOBUFS);
-			rw->addr = (unsigned long) buf;
-			rw->len = sqe_len;
-		}
-
-		ret = import_single_range(ddir, buf, sqe_len, s->fast_iov, iter);
-		if (ret)
-			return ERR_PTR(ret);
-		return NULL;
-	}
-
-	iovec = s->fast_iov;
-	if (req->flags & REQ_F_BUFFER_SELECT) {
-		ret = io_iov_buffer_select(req, iovec, issue_flags);
-		if (ret)
-			return ERR_PTR(ret);
-		iov_iter_init(iter, ddir, iovec, 1, iovec->iov_len);
-		return NULL;
-	}
-
-	ret = __import_iovec(ddir, buf, sqe_len, UIO_FASTIOV, &iovec, iter,
-			      req->ctx->compat);
-	if (unlikely(ret < 0))
-		return ERR_PTR(ret);
-	return iovec;
-}
-
-static inline int io_import_iovec(int rw, struct io_kiocb *req,
-				  struct iovec **iovec, struct io_rw_state *s,
-				  unsigned int issue_flags)
-{
-	*iovec = __io_import_iovec(rw, req, s, issue_flags);
-	if (unlikely(IS_ERR(*iovec)))
-		return PTR_ERR(*iovec);
-
-	iov_iter_save_state(&s->iter, &s->iter_state);
-	return 0;
-}
-
-static inline loff_t *io_kiocb_ppos(struct kiocb *kiocb)
-{
-	return (kiocb->ki_filp->f_mode & FMODE_STREAM) ? NULL : &kiocb->ki_pos;
-}
-
-/*
- * For files that don't have ->read_iter() and ->write_iter(), handle them
- * by looping over ->read() or ->write() manually.
- */
-static ssize_t loop_rw_iter(int ddir, struct io_rw *rw, struct iov_iter *iter)
-{
-	struct kiocb *kiocb = &rw->kiocb;
-	struct file *file = kiocb->ki_filp;
-	ssize_t ret = 0;
-	loff_t *ppos;
-
-	/*
-	 * Don't support polled IO through this interface, and we can't
-	 * support non-blocking either. For the latter, this just causes
-	 * the kiocb to be handled from an async context.
-	 */
-	if (kiocb->ki_flags & IOCB_HIPRI)
-		return -EOPNOTSUPP;
-	if ((kiocb->ki_flags & IOCB_NOWAIT) &&
-	    !(kiocb->ki_filp->f_flags & O_NONBLOCK))
-		return -EAGAIN;
-
-	ppos = io_kiocb_ppos(kiocb);
-
-	while (iov_iter_count(iter)) {
-		struct iovec iovec;
-		ssize_t nr;
-
-		if (!iov_iter_is_bvec(iter)) {
-			iovec = iov_iter_iovec(iter);
-		} else {
-			iovec.iov_base = u64_to_user_ptr(rw->addr);
-			iovec.iov_len = rw->len;
-		}
-
-		if (ddir == READ) {
-			nr = file->f_op->read(file, iovec.iov_base,
-					      iovec.iov_len, ppos);
-		} else {
-			nr = file->f_op->write(file, iovec.iov_base,
-					       iovec.iov_len, ppos);
-		}
-
-		if (nr < 0) {
-			if (!ret)
-				ret = nr;
-			break;
-		}
-		ret += nr;
-		if (!iov_iter_is_bvec(iter)) {
-			iov_iter_advance(iter, nr);
-		} else {
-			rw->addr += nr;
-			rw->len -= nr;
-			if (!rw->len)
-				break;
-		}
-		if (nr != iovec.iov_len)
-			break;
-	}
-
-	return ret;
-}
-
-static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec,
-			  const struct iovec *fast_iov, struct iov_iter *iter)
-{
-	struct io_async_rw *io = req->async_data;
-
-	memcpy(&io->s.iter, iter, sizeof(*iter));
-	io->free_iovec = iovec;
-	io->bytes_done = 0;
-	/* can only be fixed buffers, no need to do anything */
-	if (iov_iter_is_bvec(iter))
-		return;
-	if (!iovec) {
-		unsigned iov_off = 0;
-
-		io->s.iter.iov = io->s.fast_iov;
-		if (iter->iov != fast_iov) {
-			iov_off = iter->iov - fast_iov;
-			io->s.iter.iov += iov_off;
-		}
-		if (io->s.fast_iov != fast_iov)
-			memcpy(io->s.fast_iov + iov_off, fast_iov + iov_off,
-			       sizeof(struct iovec) * iter->nr_segs);
-	} else {
-		req->flags |= REQ_F_NEED_CLEANUP;
-	}
-}
-
 bool io_alloc_async_data(struct io_kiocb *req)
 {
 	WARN_ON_ONCE(!io_op_defs[req->opcode].async_size);
@@ -2264,448 +1478,13 @@ bool io_alloc_async_data(struct io_kiocb *req)
 	return true;
 }
 
-static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec,
-			     struct io_rw_state *s, bool force)
-{
-	if (!force && !io_op_defs[req->opcode].prep_async)
-		return 0;
-	if (!req_has_async_data(req)) {
-		struct io_async_rw *iorw;
-
-		if (io_alloc_async_data(req)) {
-			kfree(iovec);
-			return -ENOMEM;
-		}
-
-		io_req_map_rw(req, iovec, s->fast_iov, &s->iter);
-		iorw = req->async_data;
-		/* we've copied and mapped the iter, ensure state is saved */
-		iov_iter_save_state(&iorw->s.iter, &iorw->s.iter_state);
-	}
-	return 0;
-}
-
-static inline int io_rw_prep_async(struct io_kiocb *req, int rw)
-{
-	struct io_async_rw *iorw = req->async_data;
-	struct iovec *iov;
-	int ret;
-
-	/* submission path, ->uring_lock should already be taken */
-	ret = io_import_iovec(rw, req, &iov, &iorw->s, 0);
-	if (unlikely(ret < 0))
-		return ret;
-
-	iorw->bytes_done = 0;
-	iorw->free_iovec = iov;
-	if (iov)
-		req->flags |= REQ_F_NEED_CLEANUP;
-	return 0;
-}
-
-static int io_readv_prep_async(struct io_kiocb *req)
-{
-	return io_rw_prep_async(req, READ);
-}
-
-static int io_writev_prep_async(struct io_kiocb *req)
-{
-	return io_rw_prep_async(req, WRITE);
-}
-
-/*
- * This is our waitqueue callback handler, registered through __folio_lock_async()
- * when we initially tried to do the IO with the iocb armed our waitqueue.
- * This gets called when the page is unlocked, and we generally expect that to
- * happen when the page IO is completed and the page is now uptodate. This will
- * queue a task_work based retry of the operation, attempting to copy the data
- * again. If the latter fails because the page was NOT uptodate, then we will
- * do a thread based blocking retry of the operation. That's the unexpected
- * slow path.
- */
-static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode,
-			     int sync, void *arg)
-{
-	struct wait_page_queue *wpq;
-	struct io_kiocb *req = wait->private;
-	struct io_rw *rw = io_kiocb_to_cmd(req);
-	struct wait_page_key *key = arg;
-
-	wpq = container_of(wait, struct wait_page_queue, wait);
-
-	if (!wake_page_match(wpq, key))
-		return 0;
-
-	rw->kiocb.ki_flags &= ~IOCB_WAITQ;
-	list_del_init(&wait->entry);
-	io_req_task_queue(req);
-	return 1;
-}
-
-/*
- * This controls whether a given IO request should be armed for async page
- * based retry. If we return false here, the request is handed to the async
- * worker threads for retry. If we're doing buffered reads on a regular file,
- * we prepare a private wait_page_queue entry and retry the operation. This
- * will either succeed because the page is now uptodate and unlocked, or it
- * will register a callback when the page is unlocked at IO completion. Through
- * that callback, io_uring uses task_work to setup a retry of the operation.
- * That retry will attempt the buffered read again. The retry will generally
- * succeed, or in rare cases where it fails, we then fall back to using the
- * async worker threads for a blocking retry.
- */
-static bool io_rw_should_retry(struct io_kiocb *req)
-{
-	struct io_async_rw *io = req->async_data;
-	struct wait_page_queue *wait = &io->wpq;
-	struct io_rw *rw = io_kiocb_to_cmd(req);
-	struct kiocb *kiocb = &rw->kiocb;
-
-	/* never retry for NOWAIT, we just complete with -EAGAIN */
-	if (req->flags & REQ_F_NOWAIT)
-		return false;
-
-	/* Only for buffered IO */
-	if (kiocb->ki_flags & (IOCB_DIRECT | IOCB_HIPRI))
-		return false;
-
-	/*
-	 * just use poll if we can, and don't attempt if the fs doesn't
-	 * support callback based unlocks
-	 */
-	if (file_can_poll(req->file) || !(req->file->f_mode & FMODE_BUF_RASYNC))
-		return false;
-
-	wait->wait.func = io_async_buf_func;
-	wait->wait.private = req;
-	wait->wait.flags = 0;
-	INIT_LIST_HEAD(&wait->wait.entry);
-	kiocb->ki_flags |= IOCB_WAITQ;
-	kiocb->ki_flags &= ~IOCB_NOWAIT;
-	kiocb->ki_waitq = wait;
-	return true;
-}
-
-static inline int io_iter_do_read(struct io_rw *rw, struct iov_iter *iter)
-{
-	struct file *file = rw->kiocb.ki_filp;
-
-	if (likely(file->f_op->read_iter))
-		return call_read_iter(file, &rw->kiocb, iter);
-	else if (file->f_op->read)
-		return loop_rw_iter(READ, rw, iter);
-	else
-		return -EINVAL;
-}
-
-static bool need_read_all(struct io_kiocb *req)
-{
-	return req->flags & REQ_F_ISREG ||
-		S_ISBLK(file_inode(req->file)->i_mode);
-}
-
-static int io_rw_init_file(struct io_kiocb *req, fmode_t mode)
-{
-	struct io_rw *rw = io_kiocb_to_cmd(req);
-	struct kiocb *kiocb = &rw->kiocb;
-	struct io_ring_ctx *ctx = req->ctx;
-	struct file *file = req->file;
-	int ret;
-
-	if (unlikely(!file || !(file->f_mode & mode)))
-		return -EBADF;
-
-	if (!io_req_ffs_set(req))
-		req->flags |= io_file_get_flags(file) << REQ_F_SUPPORT_NOWAIT_BIT;
-
-	kiocb->ki_flags = iocb_flags(file);
-	ret = kiocb_set_rw_flags(kiocb, rw->flags);
-	if (unlikely(ret))
-		return ret;
-
-	/*
-	 * If the file is marked O_NONBLOCK, still allow retry for it if it
-	 * supports async. Otherwise it's impossible to use O_NONBLOCK files
-	 * reliably. If not, or it IOCB_NOWAIT is set, don't retry.
-	 */
-	if ((kiocb->ki_flags & IOCB_NOWAIT) ||
-	    ((file->f_flags & O_NONBLOCK) && !io_file_supports_nowait(req)))
-		req->flags |= REQ_F_NOWAIT;
-
-	if (ctx->flags & IORING_SETUP_IOPOLL) {
-		if (!(kiocb->ki_flags & IOCB_DIRECT) || !file->f_op->iopoll)
-			return -EOPNOTSUPP;
-
-		kiocb->private = NULL;
-		kiocb->ki_flags |= IOCB_HIPRI | IOCB_ALLOC_CACHE;
-		kiocb->ki_complete = io_complete_rw_iopoll;
-		req->iopoll_completed = 0;
-	} else {
-		if (kiocb->ki_flags & IOCB_HIPRI)
-			return -EINVAL;
-		kiocb->ki_complete = io_complete_rw;
-	}
-
-	return 0;
-}
-
-static int io_read(struct io_kiocb *req, unsigned int issue_flags)
-{
-	struct io_rw *rw = io_kiocb_to_cmd(req);
-	struct io_rw_state __s, *s = &__s;
-	struct iovec *iovec;
-	struct kiocb *kiocb = &rw->kiocb;
-	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
-	struct io_async_rw *io;
-	ssize_t ret, ret2;
-	loff_t *ppos;
-
-	if (!req_has_async_data(req)) {
-		ret = io_import_iovec(READ, req, &iovec, s, issue_flags);
-		if (unlikely(ret < 0))
-			return ret;
-	} else {
-		io = req->async_data;
-		s = &io->s;
-
-		/*
-		 * Safe and required to re-import if we're using provided
-		 * buffers, as we dropped the selected one before retry.
-		 */
-		if (io_do_buffer_select(req)) {
-			ret = io_import_iovec(READ, req, &iovec, s, issue_flags);
-			if (unlikely(ret < 0))
-				return ret;
-		}
-
-		/*
-		 * We come here from an earlier attempt, restore our state to
-		 * match in case it doesn't. It's cheap enough that we don't
-		 * need to make this conditional.
-		 */
-		iov_iter_restore(&s->iter, &s->iter_state);
-		iovec = NULL;
-	}
-	ret = io_rw_init_file(req, FMODE_READ);
-	if (unlikely(ret)) {
-		kfree(iovec);
-		return ret;
-	}
-	req->cqe.res = iov_iter_count(&s->iter);
-
-	if (force_nonblock) {
-		/* If the file doesn't support async, just async punt */
-		if (unlikely(!io_file_supports_nowait(req))) {
-			ret = io_setup_async_rw(req, iovec, s, true);
-			return ret ?: -EAGAIN;
-		}
-		kiocb->ki_flags |= IOCB_NOWAIT;
-	} else {
-		/* Ensure we clear previously set non-block flag */
-		kiocb->ki_flags &= ~IOCB_NOWAIT;
-	}
-
-	ppos = io_kiocb_update_pos(req);
-
-	ret = rw_verify_area(READ, req->file, ppos, req->cqe.res);
-	if (unlikely(ret)) {
-		kfree(iovec);
-		return ret;
-	}
-
-	ret = io_iter_do_read(rw, &s->iter);
-
-	if (ret == -EAGAIN || (req->flags & REQ_F_REISSUE)) {
-		req->flags &= ~REQ_F_REISSUE;
-		/* if we can poll, just do that */
-		if (req->opcode == IORING_OP_READ && file_can_poll(req->file))
-			return -EAGAIN;
-		/* IOPOLL retry should happen for io-wq threads */
-		if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL))
-			goto done;
-		/* no retry on NONBLOCK nor RWF_NOWAIT */
-		if (req->flags & REQ_F_NOWAIT)
-			goto done;
-		ret = 0;
-	} else if (ret == -EIOCBQUEUED) {
-		goto out_free;
-	} else if (ret == req->cqe.res || ret <= 0 || !force_nonblock ||
-		   (req->flags & REQ_F_NOWAIT) || !need_read_all(req)) {
-		/* read all, failed, already did sync or don't want to retry */
-		goto done;
-	}
-
-	/*
-	 * Don't depend on the iter state matching what was consumed, or being
-	 * untouched in case of error. Restore it and we'll advance it
-	 * manually if we need to.
-	 */
-	iov_iter_restore(&s->iter, &s->iter_state);
-
-	ret2 = io_setup_async_rw(req, iovec, s, true);
-	if (ret2)
-		return ret2;
-
-	iovec = NULL;
-	io = req->async_data;
-	s = &io->s;
-	/*
-	 * Now use our persistent iterator and state, if we aren't already.
-	 * We've restored and mapped the iter to match.
-	 */
-
-	do {
-		/*
-		 * We end up here because of a partial read, either from
-		 * above or inside this loop. Advance the iter by the bytes
-		 * that were consumed.
-		 */
-		iov_iter_advance(&s->iter, ret);
-		if (!iov_iter_count(&s->iter))
-			break;
-		io->bytes_done += ret;
-		iov_iter_save_state(&s->iter, &s->iter_state);
-
-		/* if we can retry, do so with the callbacks armed */
-		if (!io_rw_should_retry(req)) {
-			kiocb->ki_flags &= ~IOCB_WAITQ;
-			return -EAGAIN;
-		}
-
-		/*
-		 * Now retry read with the IOCB_WAITQ parts set in the iocb. If
-		 * we get -EIOCBQUEUED, then we'll get a notification when the
-		 * desired page gets unlocked. We can also get a partial read
-		 * here, and if we do, then just retry at the new offset.
-		 */
-		ret = io_iter_do_read(rw, &s->iter);
-		if (ret == -EIOCBQUEUED)
-			return IOU_ISSUE_SKIP_COMPLETE;
-		/* we got some bytes, but not all. retry. */
-		kiocb->ki_flags &= ~IOCB_WAITQ;
-		iov_iter_restore(&s->iter, &s->iter_state);
-	} while (ret > 0);
-done:
-	kiocb_done(req, ret, issue_flags);
-out_free:
-	/* it's faster to check here then delegate to kfree */
-	if (iovec)
-		kfree(iovec);
-	return IOU_ISSUE_SKIP_COMPLETE;
-}
-
-static int io_write(struct io_kiocb *req, unsigned int issue_flags)
-{
-	struct io_rw *rw = io_kiocb_to_cmd(req);
-	struct io_rw_state __s, *s = &__s;
-	struct iovec *iovec;
-	struct kiocb *kiocb = &rw->kiocb;
-	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
-	ssize_t ret, ret2;
-	loff_t *ppos;
-
-	if (!req_has_async_data(req)) {
-		ret = io_import_iovec(WRITE, req, &iovec, s, issue_flags);
-		if (unlikely(ret < 0))
-			return ret;
-	} else {
-		struct io_async_rw *io = req->async_data;
-
-		s = &io->s;
-		iov_iter_restore(&s->iter, &s->iter_state);
-		iovec = NULL;
-	}
-	ret = io_rw_init_file(req, FMODE_WRITE);
-	if (unlikely(ret)) {
-		kfree(iovec);
-		return ret;
-	}
-	req->cqe.res = iov_iter_count(&s->iter);
-
-	if (force_nonblock) {
-		/* If the file doesn't support async, just async punt */
-		if (unlikely(!io_file_supports_nowait(req)))
-			goto copy_iov;
-
-		/* file path doesn't support NOWAIT for non-direct_IO */
-		if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT) &&
-		    (req->flags & REQ_F_ISREG))
-			goto copy_iov;
-
-		kiocb->ki_flags |= IOCB_NOWAIT;
-	} else {
-		/* Ensure we clear previously set non-block flag */
-		kiocb->ki_flags &= ~IOCB_NOWAIT;
-	}
-
-	ppos = io_kiocb_update_pos(req);
-
-	ret = rw_verify_area(WRITE, req->file, ppos, req->cqe.res);
-	if (unlikely(ret))
-		goto out_free;
-
-	/*
-	 * Open-code file_start_write here to grab freeze protection,
-	 * which will be released by another thread in
-	 * io_complete_rw().  Fool lockdep by telling it the lock got
-	 * released so that it doesn't complain about the held lock when
-	 * we return to userspace.
-	 */
-	if (req->flags & REQ_F_ISREG) {
-		sb_start_write(file_inode(req->file)->i_sb);
-		__sb_writers_release(file_inode(req->file)->i_sb,
-					SB_FREEZE_WRITE);
-	}
-	kiocb->ki_flags |= IOCB_WRITE;
-
-	if (likely(req->file->f_op->write_iter))
-		ret2 = call_write_iter(req->file, kiocb, &s->iter);
-	else if (req->file->f_op->write)
-		ret2 = loop_rw_iter(WRITE, rw, &s->iter);
-	else
-		ret2 = -EINVAL;
-
-	if (req->flags & REQ_F_REISSUE) {
-		req->flags &= ~REQ_F_REISSUE;
-		ret2 = -EAGAIN;
-	}
-
-	/*
-	 * Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just
-	 * retry them without IOCB_NOWAIT.
-	 */
-	if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT))
-		ret2 = -EAGAIN;
-	/* no retry on NONBLOCK nor RWF_NOWAIT */
-	if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT))
-		goto done;
-	if (!force_nonblock || ret2 != -EAGAIN) {
-		/* IOPOLL retry should happen for io-wq threads */
-		if (ret2 == -EAGAIN && (req->ctx->flags & IORING_SETUP_IOPOLL))
-			goto copy_iov;
-done:
-		kiocb_done(req, ret2, issue_flags);
-		ret = IOU_ISSUE_SKIP_COMPLETE;
-	} else {
-copy_iov:
-		iov_iter_restore(&s->iter, &s->iter_state);
-		ret = io_setup_async_rw(req, iovec, s, false);
-		return ret ?: -EAGAIN;
-	}
-out_free:
-	/* it's reportedly faster than delegating the null check to kfree() */
-	if (iovec)
-		kfree(iovec);
-	return ret;
-}
-
 static __maybe_unused int io_eopnotsupp_prep(struct io_kiocb *kiocb,
 					     const struct io_uring_sqe *sqe)
 {
 	return -EOPNOTSUPP;
 }
 
-static int io_req_prep_async(struct io_kiocb *req)
+int io_req_prep_async(struct io_kiocb *req)
 {
 	const struct io_op_def *def = &io_op_defs[req->opcode];