From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Sat, 18 Sep 2021 12:49:45 +0000 (+0200)
Subject: 5.14-stable patches
X-Git-Tag: v4.4.284~61
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2f370a845d534b62df103559438bf55a81957198;p=thirdparty%2Fkernel%2Fstable-queue.git

5.14-stable patches

added patches:
	io_uring-allow-retry-for-o_nonblock-if-async-is-supported.patch
---

diff --git a/queue-5.14/io_uring-allow-retry-for-o_nonblock-if-async-is-supported.patch b/queue-5.14/io_uring-allow-retry-for-o_nonblock-if-async-is-supported.patch
new file mode 100644
index 00000000000..8d36e588400
--- /dev/null
+++ b/queue-5.14/io_uring-allow-retry-for-o_nonblock-if-async-is-supported.patch
@@ -0,0 +1,69 @@
+From foo@baz Sat Sep 18 02:46:52 PM CEST 2021
+From: Jens Axboe <axboe@kernel.dk>
+Date: Tue, 14 Sep 2021 11:08:37 -0600
+Subject: io_uring: allow retry for O_NONBLOCK if async is supported
+
+From: Jens Axboe <axboe@kernel.dk>
+
+commit 5d329e1286b0a040264e239b80257c937f6e685f upstream.
+
+A common complaint is that using O_NONBLOCK files with io_uring can be a
+bit of a pain. Be a bit nicer and allow normal retry IFF the file does
+support async behavior. This makes it possible to use io_uring more
+reliably with O_NONBLOCK files, for use cases where it either isn't
+possible or feasible to modify the file flags.
+
+Cc: stable@vger.kernel.org
+Reported-and-tested-by: Dan Melnic <dmm@fb.com>
+Signed-off-by: Jens Axboe <axboe@kernel.dk>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ fs/io_uring.c |   16 +++++++++++-----
+ 1 file changed, 11 insertions(+), 5 deletions(-)
+
+--- a/fs/io_uring.c
++++ b/fs/io_uring.c
+@@ -2683,7 +2683,8 @@ static bool io_file_supports_async(struc
+ 	return __io_file_supports_async(req->file, rw);
+ }
+ 
+-static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
++static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
++		      int rw)
+ {
+ 	struct io_ring_ctx *ctx = req->ctx;
+ 	struct kiocb *kiocb = &req->rw.kiocb;
+@@ -2705,8 +2706,13 @@ static int io_prep_rw(struct io_kiocb *r
+ 	if (unlikely(ret))
+ 		return ret;
+ 
+-	/* don't allow async punt for O_NONBLOCK or RWF_NOWAIT */
+-	if ((kiocb->ki_flags & IOCB_NOWAIT) || (file->f_flags & O_NONBLOCK))
++	/*
++	 * 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, rw)))
+ 		req->flags |= REQ_F_NOWAIT;
+ 
+ 	ioprio = READ_ONCE(sqe->ioprio);
+@@ -3193,7 +3199,7 @@ static int io_read_prep(struct io_kiocb
+ {
+ 	if (unlikely(!(req->file->f_mode & FMODE_READ)))
+ 		return -EBADF;
+-	return io_prep_rw(req, sqe);
++	return io_prep_rw(req, sqe, READ);
+ }
+ 
+ /*
+@@ -3382,7 +3388,7 @@ static int io_write_prep(struct io_kiocb
+ {
+ 	if (unlikely(!(req->file->f_mode & FMODE_WRITE)))
+ 		return -EBADF;
+-	return io_prep_rw(req, sqe);
++	return io_prep_rw(req, sqe, WRITE);
+ }
+ 
+ static int io_write(struct io_kiocb *req, unsigned int issue_flags)
diff --git a/queue-5.14/series b/queue-5.14/series
index b55d0cb1215..abfb34aca70 100644
--- a/queue-5.14/series
+++ b/queue-5.14/series
@@ -19,3 +19,4 @@ drm-amdgpu-move-iommu_resume-before-ip-init-resume.patch
 drm-amd-pm-fix-the-issue-of-uploading-powerplay-table.patch
 drm-amdkfd-separate-kfd_iommu_resume-from-kfd_resume.patch
 drm-radeon-pass-drm-dev-radeon_agp_head_init-directly.patch
+io_uring-allow-retry-for-o_nonblock-if-async-is-supported.patch