[PATCH 1/2] io_uring: split logic of force_nonblock

[Hao Xu <haoxu@linux.alibaba.com>]

Currently force_nonblock stands for three meanings:
 - nowait or not
 - in an io-worker or not(hold uring_lock or not)

Let's split the logic to two flags, IO_URING_F_NONBLOCK and
IO_URING_F_UNLOCKED for convenience of the next patch.

Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
---
 fs/io_uring.c | 50 ++++++++++++++++++++++++++++----------------------
 1 file changed, 28 insertions(+), 22 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index b6da03c26122..727cad6c36fc 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -199,6 +199,7 @@ struct io_rings {
 
 enum io_uring_cmd_flags {
 	IO_URING_F_COMPLETE_DEFER	= 1,
+	IO_URING_F_UNLOCKED		= 2,
 	/* int's last bit, sign checks are usually faster than a bit test */
 	IO_URING_F_NONBLOCK		= INT_MIN,
 };
@@ -2926,7 +2927,7 @@ static void kiocb_done(struct kiocb *kiocb, ssize_t ret,
 			struct io_ring_ctx *ctx = req->ctx;
 
 			req_set_fail(req);
-			if (!(issue_flags & IO_URING_F_NONBLOCK)) {
+			if (issue_flags & IO_URING_F_UNLOCKED) {
 				mutex_lock(&ctx->uring_lock);
 				__io_req_complete(req, issue_flags, ret, cflags);
 				mutex_unlock(&ctx->uring_lock);
@@ -3036,7 +3037,7 @@ static struct io_buffer *io_buffer_select(struct io_kiocb *req, size_t *len,
 {
 	struct io_buffer *kbuf = req->kbuf;
 	struct io_buffer *head;
-	bool needs_lock = !(issue_flags & IO_URING_F_NONBLOCK);
+	bool needs_lock = issue_flags & IO_URING_F_UNLOCKED;
 
 	if (req->flags & REQ_F_BUFFER_SELECTED)
 		return kbuf;
@@ -3341,7 +3342,7 @@ static inline int io_rw_prep_async(struct io_kiocb *req, int rw)
 	int ret;
 
 	/* submission path, ->uring_lock should already be taken */
-	ret = io_import_iovec(rw, req, &iov, &iorw->s, IO_URING_F_NONBLOCK);
+	ret = io_import_iovec(rw, req, &iov, &iorw->s, 0);
 	if (unlikely(ret < 0))
 		return ret;
 
@@ -3452,6 +3453,7 @@ static int io_read(struct io_kiocb *req, unsigned int issue_flags)
 	struct iovec *iovec;
 	struct kiocb *kiocb = &req->rw.kiocb;
 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
+	bool in_worker = issue_flags & IO_URING_F_UNLOCKED;
 	struct io_async_rw *rw;
 	ssize_t ret, ret2;
 
@@ -3495,7 +3497,7 @@ static int io_read(struct io_kiocb *req, unsigned int issue_flags)
 	if (ret == -EAGAIN || (req->flags & REQ_F_REISSUE)) {
 		req->flags &= ~REQ_F_REISSUE;
 		/* IOPOLL retry should happen for io-wq threads */
-		if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL))
+		if (in_worker && !(req->ctx->flags & IORING_SETUP_IOPOLL))
 			goto done;
 		/* no retry on NONBLOCK nor RWF_NOWAIT */
 		if (req->flags & REQ_F_NOWAIT)
@@ -3503,7 +3505,7 @@ static int io_read(struct io_kiocb *req, unsigned int issue_flags)
 		ret = 0;
 	} else if (ret == -EIOCBQUEUED) {
 		goto out_free;
-	} else if (ret == req->result || ret <= 0 || !force_nonblock ||
+	} else if (ret == req->result || ret <= 0 || in_worker ||
 		   (req->flags & REQ_F_NOWAIT) || !need_read_all(req)) {
 		/* read all, failed, already did sync or don't want to retry */
 		goto done;
@@ -3581,6 +3583,7 @@ static int io_write(struct io_kiocb *req, unsigned int issue_flags)
 	struct iovec *iovec;
 	struct kiocb *kiocb = &req->rw.kiocb;
 	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
+	bool in_worker = issue_flags & IO_URING_F_UNLOCKED;
 	ssize_t ret, ret2;
 
 	if (!req_has_async_data(req)) {
@@ -3651,7 +3654,7 @@ static int io_write(struct io_kiocb *req, unsigned int issue_flags)
 	/* no retry on NONBLOCK nor RWF_NOWAIT */
 	if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT))
 		goto done;
-	if (!force_nonblock || ret2 != -EAGAIN) {
+	if (in_worker || ret2 != -EAGAIN) {
 		/* IOPOLL retry should happen for io-wq threads */
 		if ((req->ctx->flags & IORING_SETUP_IOPOLL) && ret2 == -EAGAIN)
 			goto copy_iov;
@@ -4314,9 +4317,9 @@ static int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags)
 	struct io_ring_ctx *ctx = req->ctx;
 	struct io_buffer *head;
 	int ret = 0;
-	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
+	bool needs_lock = issue_flags & IO_URING_F_UNLOCKED;
 
-	io_ring_submit_lock(ctx, !force_nonblock);
+	io_ring_submit_lock(ctx, needs_lock);
 
 	lockdep_assert_held(&ctx->uring_lock);
 
@@ -4329,7 +4332,7 @@ static int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags)
 
 	/* complete before unlock, IOPOLL may need the lock */
 	__io_req_complete(req, issue_flags, ret, 0);
-	io_ring_submit_unlock(ctx, !force_nonblock);
+	io_ring_submit_unlock(ctx, needs_lock);
 	return 0;
 }
 
@@ -4401,9 +4404,9 @@ static int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags)
 	struct io_ring_ctx *ctx = req->ctx;
 	struct io_buffer *head, *list;
 	int ret = 0;
-	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
+	bool needs_lock = issue_flags & IO_URING_F_UNLOCKED;
 
-	io_ring_submit_lock(ctx, !force_nonblock);
+	io_ring_submit_lock(ctx, needs_lock);
 
 	lockdep_assert_held(&ctx->uring_lock);
 
@@ -4419,7 +4422,7 @@ static int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags)
 		req_set_fail(req);
 	/* complete before unlock, IOPOLL may need the lock */
 	__io_req_complete(req, issue_flags, ret, 0);
-	io_ring_submit_unlock(ctx, !force_nonblock);
+	io_ring_submit_unlock(ctx, needs_lock);
 	return 0;
 }
 
@@ -6279,6 +6282,7 @@ static int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags)
 {
 	struct io_ring_ctx *ctx = req->ctx;
 	u64 sqe_addr = req->cancel.addr;
+	bool needs_lock = issue_flags & IO_URING_F_UNLOCKED;
 	struct io_tctx_node *node;
 	int ret;
 
@@ -6287,7 +6291,7 @@ static int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags)
 		goto done;
 
 	/* slow path, try all io-wq's */
-	io_ring_submit_lock(ctx, !(issue_flags & IO_URING_F_NONBLOCK));
+	io_ring_submit_lock(ctx, needs_lock);
 	ret = -ENOENT;
 	list_for_each_entry(node, &ctx->tctx_list, ctx_node) {
 		struct io_uring_task *tctx = node->task->io_uring;
@@ -6296,7 +6300,7 @@ static int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags)
 		if (ret != -ENOENT)
 			break;
 	}
-	io_ring_submit_unlock(ctx, !(issue_flags & IO_URING_F_NONBLOCK));
+	io_ring_submit_unlock(ctx, needs_lock);
 done:
 	if (ret < 0)
 		req_set_fail(req);
@@ -6323,6 +6327,7 @@ static int io_rsrc_update_prep(struct io_kiocb *req,
 static int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
 {
 	struct io_ring_ctx *ctx = req->ctx;
+	bool needs_lock = issue_flags & IO_URING_F_UNLOCKED;
 	struct io_uring_rsrc_update2 up;
 	int ret;
 
@@ -6332,10 +6337,10 @@ static int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
 	up.tags = 0;
 	up.resv = 0;
 
-	io_ring_submit_lock(ctx, !(issue_flags & IO_URING_F_NONBLOCK));
+	io_ring_submit_lock(ctx, needs_lock);
 	ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE,
 					&up, req->rsrc_update.nr_args);
-	io_ring_submit_unlock(ctx, !(issue_flags & IO_URING_F_NONBLOCK));
+	io_ring_submit_unlock(ctx, needs_lock);
 
 	if (ret < 0)
 		req_set_fail(req);
@@ -6745,7 +6750,7 @@ static void io_wq_submit_work(struct io_wq_work *work)
 
 	if (!ret) {
 		do {
-			ret = io_issue_sqe(req, 0);
+			ret = io_issue_sqe(req, IO_URING_F_UNLOCKED);
 			/*
 			 * We can get EAGAIN for polled IO even though we're
 			 * forcing a sync submission from here, since we can't
@@ -8333,12 +8338,12 @@ static int io_install_fixed_file(struct io_kiocb *req, struct file *file,
 				 unsigned int issue_flags, u32 slot_index)
 {
 	struct io_ring_ctx *ctx = req->ctx;
-	bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
+	bool needs_lock = issue_flags & IO_URING_F_UNLOCKED;
 	bool needs_switch = false;
 	struct io_fixed_file *file_slot;
 	int ret = -EBADF;
 
-	io_ring_submit_lock(ctx, !force_nonblock);
+	io_ring_submit_lock(ctx, needs_lock);
 	if (file->f_op == &io_uring_fops)
 		goto err;
 	ret = -ENXIO;
@@ -8379,7 +8384,7 @@ static int io_install_fixed_file(struct io_kiocb *req, struct file *file,
 err:
 	if (needs_switch)
 		io_rsrc_node_switch(ctx, ctx->file_data);
-	io_ring_submit_unlock(ctx, !force_nonblock);
+	io_ring_submit_unlock(ctx, needs_lock);
 	if (ret)
 		fput(file);
 	return ret;
@@ -8389,11 +8394,12 @@ static int io_close_fixed(struct io_kiocb *req, unsigned int issue_flags)
 {
 	unsigned int offset = req->close.file_slot - 1;
 	struct io_ring_ctx *ctx = req->ctx;
+	bool needs_lock = issue_flags & IO_URING_F_UNLOCKED;
 	struct io_fixed_file *file_slot;
 	struct file *file;
 	int ret, i;
 
-	io_ring_submit_lock(ctx, !(issue_flags & IO_URING_F_NONBLOCK));
+	io_ring_submit_lock(ctx, needs_lock);
 	ret = -ENXIO;
 	if (unlikely(!ctx->file_data))
 		goto out;
@@ -8419,7 +8425,7 @@ static int io_close_fixed(struct io_kiocb *req, unsigned int issue_flags)
 	io_rsrc_node_switch(ctx, ctx->file_data);
 	ret = 0;
 out:
-	io_ring_submit_unlock(ctx, !(issue_flags & IO_URING_F_NONBLOCK));
+	io_ring_submit_unlock(ctx, needs_lock);
 	return ret;
 }
 
-- 
2.24.4