provided buffer recycling fixes

PATCH In review Pavel Begunkov 2 participants 9 messages Feb 10, 2025 – Feb 12, 2025 Stable branch

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Pavel Begunkov

author

2025-02-10 15:21 UTC #0 lore raw

cover provided buffer recycling fixes

Fixes for the provided buffers for not allowing kbufs to cross a single execution section. Upstream had most of it already fixed by chance, which is why all 3 patches refer to a single upstream commit.

Pavel Begunkov (3):
io_uring: fix multishots with selected buffers
io_uring: fix io_req_prep_async with provided buffers io_uring/rw: commit provided buffer state on async

 io_uring/io_uring.c |  5 ++++-
 io_uring/poll.c     |  2 ++
 io_uring/rw.c       | 10 ++++++++++
 3 files changed, 16 insertions(+), 1 deletion(-)

Signature · 1 line

2.47.1

Pavel Begunkov

author

2025-02-10 15:21 UTC #1 lore raw

PATCH 1/3 io_uring: fix multishots with selected buffers

[ upstream commit d63b0e8a628e62ca85a0f7915230186bb92f8bb4 ]

We do io_kbuf_recycle() when arming a poll but every iteration of a multishot can grab more buffers, which is why we need to flush the kbuf ring state before continuing with waiting.

Cc [email protected]

Fixes b3fdea6ecb55c ("io_uring: multishot recv")

Reported-by Muhammad Ramdhan <[email protected]>

Reported-by Bing-Jhong Billy Jheng <[email protected]>

Reported-by Jacob Soo <[email protected]>

Signed-off-by Pavel Begunkov <[email protected]>

Link https://lore.kernel.org/r/1bfc9990fe435f1fc6152ca9efeba5eb3e68339c.1738025570.git.asml.silence@gmail.com open here

Signed-off-by Jens Axboe <[email protected]>

---
 io_uring/poll.c | 2 ++
 1 file changed, 2 insertions(+)

io_uring/poll.c +2 -0

index 5cf4fffe8b6c..2824a3560245 100644
@@ -350,8 +350,10 @@ void io_poll_task_func(struct io_kiocb *req, struct io_tw_state *ts)
 
 	ret = io_poll_check_events(req, ts);
 	if (ret == IOU_POLL_NO_ACTION) {
+		io_kbuf_recycle(req, 0);
 		return;
 	} else if (ret == IOU_POLL_REQUEUE) {
+		io_kbuf_recycle(req, 0);
 		__io_poll_execute(req, 0);
 		return;
 	}

Signature · 1 line

2.47.1

Greg KH

maintainer

2025-02-11 10:16 UTC #2 lore raw

Re: [PATCH stable-6.6 1/3] io_uring: fix multishots with selected buffers

Quoted 14 lines · Pavel Begunkov

[ upstream commit d63b0e8a628e62ca85a0f7915230186bb92f8bb4 ]
We do io_kbuf_recycle() when arming a poll but every iteration of a multishot can grab more buffers, which is why we need to flush the kbuf ring state before continuing with waiting.
Cc [email protected]
Fixes b3fdea6ecb55c ("io_uring: multishot recv")
Reported-by Muhammad Ramdhan <[email protected]>
Reported-by Bing-Jhong Billy Jheng <[email protected]>
Reported-by Jacob Soo <[email protected]>
Signed-off-by Pavel Begunkov <[email protected]>
Link https://lore.kernel.org/r/1bfc9990fe435f1fc6152ca9efeba5eb3e68339c.1738025570.git.asml.silence@gmail.com open here
Signed-off-by Jens Axboe <[email protected]>

Quoted 3 lines

---
 io_uring/poll.c | 2 ++
 1 file changed, 2 insertions(+)

This is already in our 6.6.y queue, thanks!

greg k-h

Pavel Begunkov

author

2025-02-10 15:21 UTC #3 lore raw

PATCH 2/3 io_uring: fix io_req_prep_async with provided buffers

In reply to Pavel Begunkov

[ upstream commit d63b0e8a628e62ca85a0f7915230186bb92f8bb4 ]

io_req_prep_async() can import provided buffers, commit the ring state by giving up on that before, it'll be reimported later if needed.

Reported-by Muhammad Ramdhan <[email protected]>

Reported-by Bing-Jhong Billy Jheng <[email protected]>

Reported-by Jacob Soo <[email protected]>

Fixes c7fb19428d67d ("io_uring: add support for ring mapped supplied buffers")

Signed-off-by Pavel Begunkov <[email protected]>

---
 io_uring/io_uring.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

io_uring/io_uring.c +4 -1

index c7198fbcf734..b61637dad442 100644
@@ -1779,6 +1779,7 @@ int io_req_prep_async(struct io_kiocb *req)
 {
 	const struct io_cold_def *cdef = &io_cold_defs[req->opcode];
 	const struct io_issue_def *def = &io_issue_defs[req->opcode];
+	int ret;
 
 	/* assign early for deferred execution for non-fixed file */
 	if (def->needs_file && !(req->flags & REQ_F_FIXED_FILE) && !req->file)

@@ -1791,7 +1792,9 @@ int io_req_prep_async(struct io_kiocb *req)
 		if (io_alloc_async_data(req))
 			return -EAGAIN;
 	}
-	return cdef->prep_async(req);
+	ret = cdef->prep_async(req);
+	io_kbuf_recycle(req, 0);
+	return ret;
 }
 
 static u32 io_get_sequence(struct io_kiocb *req)

Signature · 1 line

2.47.1

Greg KH

maintainer

2025-02-11 10:17 UTC #4 lore raw

Re: [PATCH stable-6.6 2/3] io_uring: fix io_req_prep_async with provided buffers

Quoted 1 line · Pavel Begunkov

[ upstream commit d63b0e8a628e62ca85a0f7915230186bb92f8bb4 ]

Nope, wrong git id :(

Can you redo this series with the right one?

thanks,

greg k-h

Pavel Begunkov

author

2025-02-10 15:21 UTC #5 lore raw

PATCH 3/3 io_uring/rw: commit provided buffer state on async

In reply to Pavel Begunkov

[ upstream commit d63b0e8a628e62ca85a0f7915230186bb92f8bb4 ]

When we get -EIOCBQUEUED, we need to ensure that the buffer is consumed from the provided buffer ring, which can be done with io_kbuf_recycle()
+ REQ_F_PARTIAL_IO.

Reported-by Muhammad Ramdhan <[email protected]>

Reported-by Bing-Jhong Billy Jheng <[email protected]>

Reported-by Jacob Soo <[email protected]>

Fixes c7fb19428d67d ("io_uring: add support for ring mapped supplied buffers")

Signed-off-by Pavel Begunkov <[email protected]>

---
 io_uring/rw.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

io_uring/rw.c +10 -0

index a62f84e28bac..75b001febb4d 100644
@@ -793,6 +793,8 @@ static int __io_read(struct io_kiocb *req, unsigned int issue_flags)
 			goto done;
 		ret = 0;
 	} else if (ret == -EIOCBQUEUED) {
+		req->flags |= REQ_F_PARTIAL_IO;
+		io_kbuf_recycle(req, issue_flags);
 		if (iovec)
 			kfree(iovec);
 		return IOU_ISSUE_SKIP_COMPLETE;

@@ -816,6 +818,9 @@ static int __io_read(struct io_kiocb *req, unsigned int issue_flags)
 		goto done;
 	}
 
+	req->flags |= REQ_F_PARTIAL_IO;
+	io_kbuf_recycle(req, issue_flags);
+
 	io = req->async_data;
 	s = &io->s;
 	/*

@@ -956,6 +961,11 @@ int io_write(struct io_kiocb *req, unsigned int issue_flags)
 	else
 		ret2 = -EINVAL;
 
+	if (ret2 == -EIOCBQUEUED) {
+		req->flags |= REQ_F_PARTIAL_IO;
+		io_kbuf_recycle(req, issue_flags);
+	}
+
 	if (req->flags & REQ_F_REISSUE) {
 		req->flags &= ~REQ_F_REISSUE;
 		ret2 = -EAGAIN;

Signature · 1 line

2.47.1

Greg KH

maintainer

2025-02-11 10:16 UTC #6 lore raw

Re: [PATCH stable-6.6 3/3] io_uring/rw: commit provided buffer state on async

Quoted 1 line · Pavel Begunkov

[ upstream commit d63b0e8a628e62ca85a0f7915230186bb92f8bb4 ]

Wrong commit id :(

Let me figure out what went wrong here...

Greg KH

maintainer

2025-02-11 10:18 UTC #7 lore raw

In reply to Pavel Begunkov

Quoted 3 lines · Pavel Begunkov

Fixes for the provided buffers for not allowing kbufs to cross a single execution section. Upstream had most of it already fixed by chance, which is why all 3 patches refer to a single upstream commit.

Ah. Ok, that makes more sense, nevermind, I should have read patch 0/X first...

I'll drop the upstream commit reference here as it's just confusing.

thanks,

greg k-h

Pavel Begunkov

author

2025-02-12 11:58 UTC #8 lore raw

Quoted 9 lines · Greg KH

Quoted 3 lines · Pavel Begunkov
Fixes for the provided buffers for not allowing kbufs to cross a single execution section. Upstream had most of it already fixed by chance, which is why all 3 patches refer to a single upstream commit.
Ah. Ok, that makes more sense, nevermind, I should have read patch 0/X first...
I'll drop the upstream commit reference here as it's just confusing.

Got it, thanks

Signature · 1 line

Pavel Begunkov