[PATCH for-next 0/4] cleanups around request preps

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* [PATCH for-next 0/4] cleanups around request preps
@ 2020-09-30 19:57 Pavel Begunkov
  2020-09-30 19:57 ` [PATCH 1/4] io_uring: set/clear IOCB_NOWAIT into io_read/write Pavel Begunkov
                   ` (4 more replies)
  0 siblings, 5 replies; 6+ messages in thread
From: Pavel Begunkov @ 2020-09-30 19:57 UTC (permalink / raw)
  To: Jens Axboe, io-uring

[3/4] is splitting io_issue_sqe() as someone once proposed. (I can't
find who it was and the thread). Hopefully, it doesn't add much
overhead.

Apart from massive deduplication, this also reduces sqe propagation
depth, that's a good thing.

Pavel Begunkov (4):
  io_uring: set/clear IOCB_NOWAIT into io_read/write
  io_uring: remove nonblock arg from io_{rw}_prep()
  io_uring: decouple issuing and req preparation
  io_uring: move req preps out of io_issue_sqe()

 fs/io_uring.c | 316 ++++++++++++--------------------------------------
 1 file changed, 77 insertions(+), 239 deletions(-)

-- 
2.24.0


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH 1/4] io_uring: set/clear IOCB_NOWAIT into io_read/write
  2020-09-30 19:57 [PATCH for-next 0/4] cleanups around request preps Pavel Begunkov
@ 2020-09-30 19:57 ` Pavel Begunkov
  2020-09-30 19:57 ` [PATCH 2/4] io_uring: remove nonblock arg from io_{rw}_prep() Pavel Begunkov
                   ` (3 subsequent siblings)
  4 siblings, 0 replies; 6+ messages in thread
From: Pavel Begunkov @ 2020-09-30 19:57 UTC (permalink / raw)
  To: Jens Axboe, io-uring

Move setting IOCB_NOWAIT from io_prep_rw() into io_read()/io_write(), so
it's set/cleared in a single place. Also remove @force_nonblock
parameter from io_prep_rw().

Signed-off-by: Pavel Begunkov <[email protected]>
---
 fs/io_uring.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index e13692f692f5..2256ecec7299 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2531,8 +2531,7 @@ static bool io_file_supports_async(struct file *file, int rw)
 	return file->f_op->write_iter != NULL;
 }
 
-static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
-		      bool force_nonblock)
+static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
 	struct io_ring_ctx *ctx = req->ctx;
 	struct kiocb *kiocb = &req->rw.kiocb;
@@ -2570,9 +2569,6 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 	if (kiocb->ki_flags & IOCB_DIRECT)
 		io_get_req_task(req);
 
-	if (force_nonblock)
-		kiocb->ki_flags |= IOCB_NOWAIT;
-
 	if (ctx->flags & IORING_SETUP_IOPOLL) {
 		if (!(kiocb->ki_flags & IOCB_DIRECT) ||
 		    !kiocb->ki_filp->f_op->iopoll)
@@ -3051,7 +3047,7 @@ static int io_read_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 {
 	ssize_t ret;
 
-	ret = io_prep_rw(req, sqe, force_nonblock);
+	ret = io_prep_rw(req, sqe);
 	if (ret)
 		return ret;
 
@@ -3185,6 +3181,9 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
 	/* Ensure we clear previously set non-block flag */
 	if (!force_nonblock)
 		kiocb->ki_flags &= ~IOCB_NOWAIT;
+	else
+		kiocb->ki_flags |= IOCB_NOWAIT;
+
 
 	/* If the file doesn't support async, just async punt */
 	if (force_nonblock && !io_file_supports_async(req->file, READ))
@@ -3273,7 +3272,7 @@ static int io_write_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 {
 	ssize_t ret;
 
-	ret = io_prep_rw(req, sqe, force_nonblock);
+	ret = io_prep_rw(req, sqe);
 	if (ret)
 		return ret;
 
@@ -3308,7 +3307,9 @@ static int io_write(struct io_kiocb *req, bool force_nonblock,
 
 	/* Ensure we clear previously set non-block flag */
 	if (!force_nonblock)
-		req->rw.kiocb.ki_flags &= ~IOCB_NOWAIT;
+		kiocb->ki_flags &= ~IOCB_NOWAIT;
+	else
+		kiocb->ki_flags |= IOCB_NOWAIT;
 
 	/* If the file doesn't support async, just async punt */
 	if (force_nonblock && !io_file_supports_async(req->file, WRITE))
-- 
2.24.0


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH 2/4] io_uring: remove nonblock arg from io_{rw}_prep()
  2020-09-30 19:57 [PATCH for-next 0/4] cleanups around request preps Pavel Begunkov
  2020-09-30 19:57 ` [PATCH 1/4] io_uring: set/clear IOCB_NOWAIT into io_read/write Pavel Begunkov
@ 2020-09-30 19:57 ` Pavel Begunkov
  2020-09-30 19:57 ` [PATCH 3/4] io_uring: decouple issuing and req preparation Pavel Begunkov
                   ` (2 subsequent siblings)
  4 siblings, 0 replies; 6+ messages in thread
From: Pavel Begunkov @ 2020-09-30 19:57 UTC (permalink / raw)
  To: Jens Axboe, io-uring

All io_*_prep() functions including io_{read,write}_prep() are called
only during submission where @force_nonblock is always true. Don't keep
propagating it and instead remove the @force_nonblock argument
from prep() altogether.

Signed-off-by: Pavel Begunkov <[email protected]>
---
 fs/io_uring.c | 23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 2256ecec7299..24f411aa4d1f 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3024,14 +3024,13 @@ static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec,
 	return 0;
 }
 
-static inline int io_rw_prep_async(struct io_kiocb *req, int rw,
-				   bool force_nonblock)
+static inline int io_rw_prep_async(struct io_kiocb *req, int rw)
 {
 	struct io_async_rw *iorw = req->async_data;
 	struct iovec *iov = iorw->fast_iov;
 	ssize_t ret;
 
-	ret = __io_import_iovec(rw, req, &iov, &iorw->iter, !force_nonblock);
+	ret = __io_import_iovec(rw, req, &iov, &iorw->iter, false);
 	if (unlikely(ret < 0))
 		return ret;
 
@@ -3042,8 +3041,7 @@ static inline int io_rw_prep_async(struct io_kiocb *req, int rw,
 	return 0;
 }
 
-static int io_read_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
-			bool force_nonblock)
+static int io_read_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
 	ssize_t ret;
 
@@ -3057,7 +3055,7 @@ static int io_read_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 	/* either don't need iovec imported or already have it */
 	if (!req->async_data)
 		return 0;
-	return io_rw_prep_async(req, READ, force_nonblock);
+	return io_rw_prep_async(req, READ);
 }
 
 /*
@@ -3267,8 +3265,7 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
 	return ret;
 }
 
-static int io_write_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
-			 bool force_nonblock)
+static int io_write_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
 	ssize_t ret;
 
@@ -3282,7 +3279,7 @@ static int io_write_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 	/* either don't need iovec imported or already have it */
 	if (!req->async_data)
 		return 0;
-	return io_rw_prep_async(req, WRITE, force_nonblock);
+	return io_rw_prep_async(req, WRITE);
 }
 
 static int io_write(struct io_kiocb *req, bool force_nonblock,
@@ -5542,12 +5539,12 @@ static int io_req_defer_prep(struct io_kiocb *req,
 	case IORING_OP_READV:
 	case IORING_OP_READ_FIXED:
 	case IORING_OP_READ:
-		ret = io_read_prep(req, sqe, true);
+		ret = io_read_prep(req, sqe);
 		break;
 	case IORING_OP_WRITEV:
 	case IORING_OP_WRITE_FIXED:
 	case IORING_OP_WRITE:
-		ret = io_write_prep(req, sqe, true);
+		ret = io_write_prep(req, sqe);
 		break;
 	case IORING_OP_POLL_ADD:
 		ret = io_poll_add_prep(req, sqe);
@@ -5769,7 +5766,7 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 	case IORING_OP_READ_FIXED:
 	case IORING_OP_READ:
 		if (sqe) {
-			ret = io_read_prep(req, sqe, force_nonblock);
+			ret = io_read_prep(req, sqe);
 			if (ret < 0)
 				break;
 		}
@@ -5779,7 +5776,7 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 	case IORING_OP_WRITE_FIXED:
 	case IORING_OP_WRITE:
 		if (sqe) {
-			ret = io_write_prep(req, sqe, force_nonblock);
+			ret = io_write_prep(req, sqe);
 			if (ret < 0)
 				break;
 		}
-- 
2.24.0


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH 3/4] io_uring: decouple issuing and req preparation
  2020-09-30 19:57 [PATCH for-next 0/4] cleanups around request preps Pavel Begunkov
  2020-09-30 19:57 ` [PATCH 1/4] io_uring: set/clear IOCB_NOWAIT into io_read/write Pavel Begunkov
  2020-09-30 19:57 ` [PATCH 2/4] io_uring: remove nonblock arg from io_{rw}_prep() Pavel Begunkov
@ 2020-09-30 19:57 ` Pavel Begunkov
  2020-09-30 19:57 ` [PATCH 4/4] io_uring: move req preps out of io_issue_sqe() Pavel Begunkov
  2020-10-01  3:01 ` [PATCH for-next 0/4] cleanups around request preps Jens Axboe
  4 siblings, 0 replies; 6+ messages in thread
From: Pavel Begunkov @ 2020-09-30 19:57 UTC (permalink / raw)
  To: Jens Axboe, io-uring

io_issue_sqe() does two things at once, trying to prepare request and
issuing them. Split it in two and deduplicate with io_defer_prep().

Signed-off-by: Pavel Begunkov <[email protected]>
---
 fs/io_uring.c | 266 +++++++++++---------------------------------------
 1 file changed, 55 insertions(+), 211 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 24f411aa4d1f..0ce0ebee4808 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5519,121 +5519,94 @@ static int io_files_update(struct io_kiocb *req, bool force_nonblock,
 	return 0;
 }
 
-static int io_req_defer_prep(struct io_kiocb *req,
-			     const struct io_uring_sqe *sqe)
+static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
-	ssize_t ret = 0;
-
-	if (!sqe)
-		return 0;
-
-	if (io_alloc_async_data(req))
-		return -EAGAIN;
-	ret = io_prep_work_files(req);
-	if (unlikely(ret))
-		return ret;
-
 	switch (req->opcode) {
 	case IORING_OP_NOP:
-		break;
+		return 0;
 	case IORING_OP_READV:
 	case IORING_OP_READ_FIXED:
 	case IORING_OP_READ:
-		ret = io_read_prep(req, sqe);
-		break;
+		return io_read_prep(req, sqe);
 	case IORING_OP_WRITEV:
 	case IORING_OP_WRITE_FIXED:
 	case IORING_OP_WRITE:
-		ret = io_write_prep(req, sqe);
-		break;
+		return io_write_prep(req, sqe);
 	case IORING_OP_POLL_ADD:
-		ret = io_poll_add_prep(req, sqe);
-		break;
+		return io_poll_add_prep(req, sqe);
 	case IORING_OP_POLL_REMOVE:
-		ret = io_poll_remove_prep(req, sqe);
-		break;
+		return io_poll_remove_prep(req, sqe);
 	case IORING_OP_FSYNC:
-		ret = io_prep_fsync(req, sqe);
-		break;
+		return io_prep_fsync(req, sqe);
 	case IORING_OP_SYNC_FILE_RANGE:
-		ret = io_prep_sfr(req, sqe);
-		break;
+		return io_prep_sfr(req, sqe);
 	case IORING_OP_SENDMSG:
 	case IORING_OP_SEND:
-		ret = io_sendmsg_prep(req, sqe);
-		break;
+		return io_sendmsg_prep(req, sqe);
 	case IORING_OP_RECVMSG:
 	case IORING_OP_RECV:
-		ret = io_recvmsg_prep(req, sqe);
-		break;
+		return io_recvmsg_prep(req, sqe);
 	case IORING_OP_CONNECT:
-		ret = io_connect_prep(req, sqe);
-		break;
+		return io_connect_prep(req, sqe);
 	case IORING_OP_TIMEOUT:
-		ret = io_timeout_prep(req, sqe, false);
-		break;
+		return io_timeout_prep(req, sqe, false);
 	case IORING_OP_TIMEOUT_REMOVE:
-		ret = io_timeout_remove_prep(req, sqe);
-		break;
+		return io_timeout_remove_prep(req, sqe);
 	case IORING_OP_ASYNC_CANCEL:
-		ret = io_async_cancel_prep(req, sqe);
-		break;
+		return io_async_cancel_prep(req, sqe);
 	case IORING_OP_LINK_TIMEOUT:
-		ret = io_timeout_prep(req, sqe, true);
-		break;
+		return io_timeout_prep(req, sqe, true);
 	case IORING_OP_ACCEPT:
-		ret = io_accept_prep(req, sqe);
-		break;
+		return io_accept_prep(req, sqe);
 	case IORING_OP_FALLOCATE:
-		ret = io_fallocate_prep(req, sqe);
-		break;
+		return io_fallocate_prep(req, sqe);
 	case IORING_OP_OPENAT:
-		ret = io_openat_prep(req, sqe);
-		break;
+		return io_openat_prep(req, sqe);
 	case IORING_OP_CLOSE:
-		ret = io_close_prep(req, sqe);
-		break;
+		return io_close_prep(req, sqe);
 	case IORING_OP_FILES_UPDATE:
-		ret = io_files_update_prep(req, sqe);
-		break;
+		return io_files_update_prep(req, sqe);
 	case IORING_OP_STATX:
-		ret = io_statx_prep(req, sqe);
-		break;
+		return io_statx_prep(req, sqe);
 	case IORING_OP_FADVISE:
-		ret = io_fadvise_prep(req, sqe);
-		break;
+		return io_fadvise_prep(req, sqe);
 	case IORING_OP_MADVISE:
-		ret = io_madvise_prep(req, sqe);
-		break;
+		return io_madvise_prep(req, sqe);
 	case IORING_OP_OPENAT2:
-		ret = io_openat2_prep(req, sqe);
-		break;
+		return io_openat2_prep(req, sqe);
 	case IORING_OP_EPOLL_CTL:
-		ret = io_epoll_ctl_prep(req, sqe);
-		break;
+		return io_epoll_ctl_prep(req, sqe);
 	case IORING_OP_SPLICE:
-		ret = io_splice_prep(req, sqe);
-		break;
+		return io_splice_prep(req, sqe);
 	case IORING_OP_PROVIDE_BUFFERS:
-		ret = io_provide_buffers_prep(req, sqe);
-		break;
+		return io_provide_buffers_prep(req, sqe);
 	case IORING_OP_REMOVE_BUFFERS:
-		ret = io_remove_buffers_prep(req, sqe);
-		break;
+		return io_remove_buffers_prep(req, sqe);
 	case IORING_OP_TEE:
-		ret = io_tee_prep(req, sqe);
-		break;
+		return io_tee_prep(req, sqe);
 	case IORING_OP_SHUTDOWN:
-		ret = io_shutdown_prep(req, sqe);
-		break;
-	default:
-		printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
-				req->opcode);
-		ret = -EINVAL;
-		break;
+		return io_shutdown_prep(req, sqe);
 	}
 
-	return ret;
+	printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
+			req->opcode);
+	return -EINVAL;
+}
+
+static int io_req_defer_prep(struct io_kiocb *req,
+			     const struct io_uring_sqe *sqe)
+{
+	int ret;
+
+	if (!sqe)
+		return 0;
+	if (io_alloc_async_data(req))
+		return -EAGAIN;
+
+	ret = io_prep_work_files(req);
+	if (unlikely(ret))
+		return ret;
+	return io_req_prep(req, sqe);
 }
 
 static u32 io_get_sequence(struct io_kiocb *req)
@@ -5758,6 +5731,12 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 	struct io_ring_ctx *ctx = req->ctx;
 	int ret;
 
+	if (sqe) {
+		ret = io_req_prep(req, sqe);
+		if (unlikely(ret < 0))
+			return ret;
+	}
+
 	switch (req->opcode) {
 	case IORING_OP_NOP:
 		ret = io_nop(req, cs);
@@ -5765,62 +5744,27 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 	case IORING_OP_READV:
 	case IORING_OP_READ_FIXED:
 	case IORING_OP_READ:
-		if (sqe) {
-			ret = io_read_prep(req, sqe);
-			if (ret < 0)
-				break;
-		}
 		ret = io_read(req, force_nonblock, cs);
 		break;
 	case IORING_OP_WRITEV:
 	case IORING_OP_WRITE_FIXED:
 	case IORING_OP_WRITE:
-		if (sqe) {
-			ret = io_write_prep(req, sqe);
-			if (ret < 0)
-				break;
-		}
 		ret = io_write(req, force_nonblock, cs);
 		break;
 	case IORING_OP_FSYNC:
-		if (sqe) {
-			ret = io_prep_fsync(req, sqe);
-			if (ret < 0)
-				break;
-		}
 		ret = io_fsync(req, force_nonblock);
 		break;
 	case IORING_OP_POLL_ADD:
-		if (sqe) {
-			ret = io_poll_add_prep(req, sqe);
-			if (ret)
-				break;
-		}
 		ret = io_poll_add(req);
 		break;
 	case IORING_OP_POLL_REMOVE:
-		if (sqe) {
-			ret = io_poll_remove_prep(req, sqe);
-			if (ret < 0)
-				break;
-		}
 		ret = io_poll_remove(req);
 		break;
 	case IORING_OP_SYNC_FILE_RANGE:
-		if (sqe) {
-			ret = io_prep_sfr(req, sqe);
-			if (ret < 0)
-				break;
-		}
 		ret = io_sync_file_range(req, force_nonblock);
 		break;
 	case IORING_OP_SENDMSG:
 	case IORING_OP_SEND:
-		if (sqe) {
-			ret = io_sendmsg_prep(req, sqe);
-			if (ret < 0)
-				break;
-		}
 		if (req->opcode == IORING_OP_SENDMSG)
 			ret = io_sendmsg(req, force_nonblock, cs);
 		else
@@ -5828,166 +5772,66 @@ static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 		break;
 	case IORING_OP_RECVMSG:
 	case IORING_OP_RECV:
-		if (sqe) {
-			ret = io_recvmsg_prep(req, sqe);
-			if (ret)
-				break;
-		}
 		if (req->opcode == IORING_OP_RECVMSG)
 			ret = io_recvmsg(req, force_nonblock, cs);
 		else
 			ret = io_recv(req, force_nonblock, cs);
 		break;
 	case IORING_OP_TIMEOUT:
-		if (sqe) {
-			ret = io_timeout_prep(req, sqe, false);
-			if (ret)
-				break;
-		}
 		ret = io_timeout(req);
 		break;
 	case IORING_OP_TIMEOUT_REMOVE:
-		if (sqe) {
-			ret = io_timeout_remove_prep(req, sqe);
-			if (ret)
-				break;
-		}
 		ret = io_timeout_remove(req);
 		break;
 	case IORING_OP_ACCEPT:
-		if (sqe) {
-			ret = io_accept_prep(req, sqe);
-			if (ret)
-				break;
-		}
 		ret = io_accept(req, force_nonblock, cs);
 		break;
 	case IORING_OP_CONNECT:
-		if (sqe) {
-			ret = io_connect_prep(req, sqe);
-			if (ret)
-				break;
-		}
 		ret = io_connect(req, force_nonblock, cs);
 		break;
 	case IORING_OP_ASYNC_CANCEL:
-		if (sqe) {
-			ret = io_async_cancel_prep(req, sqe);
-			if (ret)
-				break;
-		}
 		ret = io_async_cancel(req);
 		break;
 	case IORING_OP_FALLOCATE:
-		if (sqe) {
-			ret = io_fallocate_prep(req, sqe);
-			if (ret)
-				break;
-		}
 		ret = io_fallocate(req, force_nonblock);
 		break;
 	case IORING_OP_OPENAT:
-		if (sqe) {
-			ret = io_openat_prep(req, sqe);
-			if (ret)
-				break;
-		}
 		ret = io_openat(req, force_nonblock);
 		break;
 	case IORING_OP_CLOSE:
-		if (sqe) {
-			ret = io_close_prep(req, sqe);
-			if (ret)
-				break;
-		}
 		ret = io_close(req, force_nonblock, cs);
 		break;
 	case IORING_OP_FILES_UPDATE:
-		if (sqe) {
-			ret = io_files_update_prep(req, sqe);
-			if (ret)
-				break;
-		}
 		ret = io_files_update(req, force_nonblock, cs);
 		break;
 	case IORING_OP_STATX:
-		if (sqe) {
-			ret = io_statx_prep(req, sqe);
-			if (ret)
-				break;
-		}
 		ret = io_statx(req, force_nonblock);
 		break;
 	case IORING_OP_FADVISE:
-		if (sqe) {
-			ret = io_fadvise_prep(req, sqe);
-			if (ret)
-				break;
-		}
 		ret = io_fadvise(req, force_nonblock);
 		break;
 	case IORING_OP_MADVISE:
-		if (sqe) {
-			ret = io_madvise_prep(req, sqe);
-			if (ret)
-				break;
-		}
 		ret = io_madvise(req, force_nonblock);
 		break;
 	case IORING_OP_OPENAT2:
-		if (sqe) {
-			ret = io_openat2_prep(req, sqe);
-			if (ret)
-				break;
-		}
 		ret = io_openat2(req, force_nonblock);
 		break;
 	case IORING_OP_EPOLL_CTL:
-		if (sqe) {
-			ret = io_epoll_ctl_prep(req, sqe);
-			if (ret)
-				break;
-		}
 		ret = io_epoll_ctl(req, force_nonblock, cs);
 		break;
 	case IORING_OP_SPLICE:
-		if (sqe) {
-			ret = io_splice_prep(req, sqe);
-			if (ret < 0)
-				break;
-		}
 		ret = io_splice(req, force_nonblock);
 		break;
 	case IORING_OP_PROVIDE_BUFFERS:
-		if (sqe) {
-			ret = io_provide_buffers_prep(req, sqe);
-			if (ret)
-				break;
-		}
 		ret = io_provide_buffers(req, force_nonblock, cs);
 		break;
 	case IORING_OP_REMOVE_BUFFERS:
-		if (sqe) {
-			ret = io_remove_buffers_prep(req, sqe);
-			if (ret)
-				break;
-		}
 		ret = io_remove_buffers(req, force_nonblock, cs);
 		break;
 	case IORING_OP_TEE:
-		if (sqe) {
-			ret = io_tee_prep(req, sqe);
-			if (ret < 0)
-				break;
-		}
 		ret = io_tee(req, force_nonblock);
 		break;
 	case IORING_OP_SHUTDOWN:
-		if (sqe) {
-			ret = io_shutdown_prep(req, sqe);
-			if (ret < 0)
-				break;
-		}
 		ret = io_shutdown(req, force_nonblock);
 		break;
 	default:
-- 
2.24.0


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH 4/4] io_uring: move req preps out of io_issue_sqe()
  2020-09-30 19:57 [PATCH for-next 0/4] cleanups around request preps Pavel Begunkov
                   ` (2 preceding siblings ...)
  2020-09-30 19:57 ` [PATCH 3/4] io_uring: decouple issuing and req preparation Pavel Begunkov
@ 2020-09-30 19:57 ` Pavel Begunkov
  2020-10-01  3:01 ` [PATCH for-next 0/4] cleanups around request preps Jens Axboe
  4 siblings, 0 replies; 6+ messages in thread
From: Pavel Begunkov @ 2020-09-30 19:57 UTC (permalink / raw)
  To: Jens Axboe, io-uring

All request preparations are done only during submission, reflect it in
the code by moving io_req_prep() much earlier into io_queue_sqe().

That's much cleaner, because it doen't expose bits to async code which
it won't ever use. Also it makes the interface harder to misuse, and
there are potential places for bugs.

For instance, __io_queue() doesn't clear @sqe before proceeding to a
next linked request, that could have been disastrous, but hopefully
there are linked requests IFF sqe==NULL, so not actually a bug.

Signed-off-by: Pavel Begunkov <[email protected]>
---
 fs/io_uring.c | 30 +++++++++++++-----------------
 1 file changed, 13 insertions(+), 17 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 0ce0ebee4808..cb22225bee6c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -954,9 +954,7 @@ static int io_prep_work_files(struct io_kiocb *req);
 static void __io_clean_op(struct io_kiocb *req);
 static int io_file_get(struct io_submit_state *state, struct io_kiocb *req,
 		       int fd, struct file **out_file, bool fixed);
-static void __io_queue_sqe(struct io_kiocb *req,
-			   const struct io_uring_sqe *sqe,
-			   struct io_comp_state *cs);
+static void __io_queue_sqe(struct io_kiocb *req, struct io_comp_state *cs);
 static void io_file_put_work(struct work_struct *work);
 
 static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
@@ -1852,7 +1850,7 @@ static void __io_req_task_submit(struct io_kiocb *req)
 
 	if (!__io_sq_thread_acquire_mm(ctx)) {
 		mutex_lock(&ctx->uring_lock);
-		__io_queue_sqe(req, NULL, NULL);
+		__io_queue_sqe(req, NULL);
 		mutex_unlock(&ctx->uring_lock);
 	} else {
 		__io_req_task_cancel(req, -EFAULT);
@@ -5725,18 +5723,12 @@ static void __io_clean_op(struct io_kiocb *req)
 	}
 }
 
-static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
-			bool force_nonblock, struct io_comp_state *cs)
+static int io_issue_sqe(struct io_kiocb *req, bool force_nonblock,
+			struct io_comp_state *cs)
 {
 	struct io_ring_ctx *ctx = req->ctx;
 	int ret;
 
-	if (sqe) {
-		ret = io_req_prep(req, sqe);
-		if (unlikely(ret < 0))
-			return ret;
-	}
-
 	switch (req->opcode) {
 	case IORING_OP_NOP:
 		ret = io_nop(req, cs);
@@ -5877,7 +5869,7 @@ static struct io_wq_work *io_wq_submit_work(struct io_wq_work *work)
 
 	if (!ret) {
 		do {
-			ret = io_issue_sqe(req, NULL, false, NULL);
+			ret = io_issue_sqe(req, false, NULL);
 			/*
 			 * We can get EAGAIN for polled IO even though we're
 			 * forcing a sync submission from here, since we can't
@@ -6061,8 +6053,7 @@ static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
 	return nxt;
 }
 
-static void __io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
-			   struct io_comp_state *cs)
+static void __io_queue_sqe(struct io_kiocb *req, struct io_comp_state *cs)
 {
 	struct io_kiocb *linked_timeout;
 	struct io_kiocb *nxt;
@@ -6082,7 +6073,7 @@ static void __io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 			old_creds = override_creds(req->work.creds);
 	}
 
-	ret = io_issue_sqe(req, sqe, true, cs);
+	ret = io_issue_sqe(req, true, cs);
 
 	/*
 	 * We async punt it if the file wasn't marked NOWAIT, or if the file
@@ -6161,7 +6152,12 @@ static void io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 		req->work.flags |= IO_WQ_WORK_CONCURRENT;
 		io_queue_async_work(req);
 	} else {
-		__io_queue_sqe(req, sqe, cs);
+		if (sqe) {
+			ret = io_req_prep(req, sqe);
+			if (unlikely(ret))
+				goto fail_req;
+		}
+		__io_queue_sqe(req, cs);
 	}
 }
 
-- 
2.24.0


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH for-next 0/4] cleanups around request preps
  2020-09-30 19:57 [PATCH for-next 0/4] cleanups around request preps Pavel Begunkov
                   ` (3 preceding siblings ...)
  2020-09-30 19:57 ` [PATCH 4/4] io_uring: move req preps out of io_issue_sqe() Pavel Begunkov
@ 2020-10-01  3:01 ` Jens Axboe
  4 siblings, 0 replies; 6+ messages in thread
From: Jens Axboe @ 2020-10-01  3:01 UTC (permalink / raw)
  To: Pavel Begunkov, io-uring

On 9/30/20 1:57 PM, Pavel Begunkov wrote:
> [3/4] is splitting io_issue_sqe() as someone once proposed. (I can't
> find who it was and the thread). Hopefully, it doesn't add much
> overhead.
> 
> Apart from massive deduplication, this also reduces sqe propagation
> depth, that's a good thing.
> 
> Pavel Begunkov (4):
>   io_uring: set/clear IOCB_NOWAIT into io_read/write
>   io_uring: remove nonblock arg from io_{rw}_prep()
>   io_uring: decouple issuing and req preparation
>   io_uring: move req preps out of io_issue_sqe()
> 
>  fs/io_uring.c | 316 ++++++++++++--------------------------------------
>  1 file changed, 77 insertions(+), 239 deletions(-)

Thanks, this is awesome! Easier to read, and kills a ton of lines.
I have applied this and your standalone patches.

-- 
Jens Axboe


^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2020-10-01  3:01 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2020-09-30 19:57 [PATCH for-next 0/4] cleanups around request preps Pavel Begunkov
2020-09-30 19:57 ` [PATCH 1/4] io_uring: set/clear IOCB_NOWAIT into io_read/write Pavel Begunkov
2020-09-30 19:57 ` [PATCH 2/4] io_uring: remove nonblock arg from io_{rw}_prep() Pavel Begunkov
2020-09-30 19:57 ` [PATCH 3/4] io_uring: decouple issuing and req preparation Pavel Begunkov
2020-09-30 19:57 ` [PATCH 4/4] io_uring: move req preps out of io_issue_sqe() Pavel Begunkov
2020-10-01  3:01 ` [PATCH for-next 0/4] cleanups around request preps Jens Axboe

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