6.6-stable backports

[Jens Axboe <axboe@kernel.dk>]

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Hi,

Can you guys queue up these patches for 6.6-stable?

Thanks!

-- 
Jens Axboe


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From 1d342f04ea6252239e8c30a02b55131a4d8d8841 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Mon, 11 Sep 2023 13:31:56 -0600
Subject: [PATCH 1/3] io_uring/rw: split io_read() into a helper

Commit a08d195b586a217d76b42062f88f375a3eedda4d upstream.

Add __io_read() which does the grunt of the work, leaving the completion
side to the new io_read(). No functional changes in this patch.

Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
(cherry picked from commit a08d195b586a217d76b42062f88f375a3eedda4d)
---
 io_uring/rw.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/io_uring/rw.c b/io_uring/rw.c
index e90404c812fa..6ae29b88baf8 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -712,7 +712,7 @@ static int io_rw_init_file(struct io_kiocb *req, fmode_t mode)
 	return 0;
 }
 
-int io_read(struct io_kiocb *req, unsigned int issue_flags)
+static int __io_read(struct io_kiocb *req, unsigned int issue_flags)
 {
 	struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
 	struct io_rw_state __s, *s = &__s;
@@ -857,7 +857,18 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags)
 	/* it's faster to check here then delegate to kfree */
 	if (iovec)
 		kfree(iovec);
-	return kiocb_done(req, ret, issue_flags);
+	return ret;
+}
+
+int io_read(struct io_kiocb *req, unsigned int issue_flags)
+{
+	int ret;
+
+	ret = __io_read(req, issue_flags);
+	if (ret >= 0)
+		return kiocb_done(req, ret, issue_flags);
+
+	return ret;
 }
 
 static bool io_kiocb_start_write(struct io_kiocb *req, struct kiocb *kiocb)
-- 
2.45.2


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From 83a4219fda02c0fda93c3def2d85e952161d4651 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Tue, 10 Sep 2024 08:30:57 -0600
Subject: [PATCH 2/3] io_uring/rw: treat -EOPNOTSUPP for IOCB_NOWAIT like
 -EAGAIN

Commit c0a9d496e0fece67db777bd48550376cf2960c47 upstream.

Some file systems, ocfs2 in this case, will return -EOPNOTSUPP for
an IOCB_NOWAIT read/write attempt. While this can be argued to be
correct, the usual return value for something that requires blocking
issue is -EAGAIN.

A refactoring io_uring commit dropped calling kiocb_done() for
negative return values, which is otherwise where we already do that
transformation. To ensure we catch it in both spots, check it in
__io_read() itself as well.

Reported-by: Robert Sander <r.sander@heinlein-support.de>
Link: https://fosstodon.org/@gurubert@mastodon.gurubert.de/113112431889638440
Cc: stable@vger.kernel.org
Fixes: a08d195b586a ("io_uring/rw: split io_read() into a helper")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 io_uring/rw.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/io_uring/rw.c b/io_uring/rw.c
index 6ae29b88baf8..8a16f97f5ac3 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -778,6 +778,14 @@ static int __io_read(struct io_kiocb *req, unsigned int issue_flags)
 
 	ret = io_iter_do_read(rw, &s->iter);
 
+	/*
+	 * Some file systems like to return -EOPNOTSUPP for an IOCB_NOWAIT
+	 * issue, even though they should be returning -EAGAIN. To be safe,
+	 * retry from blocking context for either.
+	 */
+	if (ret == -EOPNOTSUPP && force_nonblock)
+		ret = -EAGAIN;
+
 	if (ret == -EAGAIN || (req->flags & REQ_F_REISSUE)) {
 		req->flags &= ~REQ_F_REISSUE;
 		/* if we can poll, just do that */
-- 
2.45.2


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From 20558ae136562a71d0033306cd66c69b630cc700 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Mon, 18 Mar 2024 22:00:28 +0000
Subject: [PATCH 3/3] io_uring/rw: avoid punting to io-wq directly

Commit 6e6b8c62120a22acd8cb759304e4cd2e3215d488 upstream.

kiocb_done() should care to specifically redirecting requests to io-wq.
Remove the hopping to tw to then queue an io-wq, return -EAGAIN and let
the core code io_uring handle offloading.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Tested-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/413564e550fe23744a970e1783dfa566291b0e6f.1710799188.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
(cherry picked from commit 6e6b8c62120a22acd8cb759304e4cd2e3215d488)
---
 io_uring/io_uring.c | 8 ++++----
 io_uring/io_uring.h | 1 -
 io_uring/rw.c       | 8 +-------
 3 files changed, 5 insertions(+), 12 deletions(-)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 70dd6a5b9647..d4de4b543199 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -492,7 +492,7 @@ static void io_prep_async_link(struct io_kiocb *req)
 	}
 }
 
-void io_queue_iowq(struct io_kiocb *req, struct io_tw_state *ts_dont_use)
+static void io_queue_iowq(struct io_kiocb *req)
 {
 	struct io_kiocb *link = io_prep_linked_timeout(req);
 	struct io_uring_task *tctx = req->task->io_uring;
@@ -1475,7 +1475,7 @@ void io_req_task_submit(struct io_kiocb *req, struct io_tw_state *ts)
 	if (unlikely(req->task->flags & PF_EXITING))
 		io_req_defer_failed(req, -EFAULT);
 	else if (req->flags & REQ_F_FORCE_ASYNC)
-		io_queue_iowq(req, ts);
+		io_queue_iowq(req);
 	else
 		io_queue_sqe(req);
 }
@@ -2040,7 +2040,7 @@ static void io_queue_async(struct io_kiocb *req, int ret)
 		break;
 	case IO_APOLL_ABORTED:
 		io_kbuf_recycle(req, 0);
-		io_queue_iowq(req, NULL);
+		io_queue_iowq(req);
 		break;
 	case IO_APOLL_OK:
 		break;
@@ -2089,7 +2089,7 @@ static void io_queue_sqe_fallback(struct io_kiocb *req)
 		if (unlikely(req->ctx->drain_active))
 			io_drain_req(req);
 		else
-			io_queue_iowq(req, NULL);
+			io_queue_iowq(req);
 	}
 }
 
diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h
index 8242820742ee..57658d24a73e 100644
--- a/io_uring/io_uring.h
+++ b/io_uring/io_uring.h
@@ -63,7 +63,6 @@ struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
 void __io_req_task_work_add(struct io_kiocb *req, unsigned flags);
 bool io_alloc_async_data(struct io_kiocb *req);
 void io_req_task_queue(struct io_kiocb *req);
-void io_queue_iowq(struct io_kiocb *req, struct io_tw_state *ts_dont_use);
 void io_req_task_complete(struct io_kiocb *req, struct io_tw_state *ts);
 void io_req_task_queue_fail(struct io_kiocb *req, int ret);
 void io_req_task_submit(struct io_kiocb *req, struct io_tw_state *ts);
diff --git a/io_uring/rw.c b/io_uring/rw.c
index 8a16f97f5ac3..a62f84e28bac 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -168,12 +168,6 @@ static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req)
 	return NULL;
 }
 
-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);
-}
-
 #ifdef CONFIG_BLOCK
 static bool io_resubmit_prep(struct io_kiocb *req)
 {
@@ -359,7 +353,7 @@ static int kiocb_done(struct io_kiocb *req, ssize_t ret,
 	if (req->flags & REQ_F_REISSUE) {
 		req->flags &= ~REQ_F_REISSUE;
 		if (io_resubmit_prep(req))
-			io_req_task_queue_reissue(req);
+			return -EAGAIN;
 		else
 			io_req_task_queue_fail(req, final_ret);
 	}
-- 
2.45.2