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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Pavel Begunkov <asml.silence@gmail.com>,
        Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 6.0 011/862] io_uring/rw: dont lose partial IO result on fail
Date:   Wed, 19 Oct 2022 10:21:38 +0200
Message-Id: <20221019083250.513888626@linuxfoundation.org>
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From: Pavel Begunkov <asml.silence@gmail.com>

commit 47b4c68660752facfa6247b1fc9ca9d722b8b601 upstream.

A partially done read/write may end up in io_req_complete_failed() and
loose the result, make sure we return the number of bytes processed.

Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/05e0879c226bcd53b441bf92868eadd4bf04e2fc.1663668091.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 io_uring/opdef.c |    6 ++++++
 io_uring/rw.c    |    8 ++++++++
 io_uring/rw.h    |    1 +
 3 files changed, 15 insertions(+)

--- a/io_uring/opdef.c
+++ b/io_uring/opdef.c
@@ -69,6 +69,7 @@ const struct io_op_def io_op_defs[] = {
 		.issue			= io_read,
 		.prep_async		= io_readv_prep_async,
 		.cleanup		= io_readv_writev_cleanup,
+		.fail			= io_rw_fail,
 	},
 	[IORING_OP_WRITEV] = {
 		.needs_file		= 1,
@@ -85,6 +86,7 @@ const struct io_op_def io_op_defs[] = {
 		.issue			= io_write,
 		.prep_async		= io_writev_prep_async,
 		.cleanup		= io_readv_writev_cleanup,
+		.fail			= io_rw_fail,
 	},
 	[IORING_OP_FSYNC] = {
 		.needs_file		= 1,
@@ -105,6 +107,7 @@ const struct io_op_def io_op_defs[] = {
 		.name			= "READ_FIXED",
 		.prep			= io_prep_rw,
 		.issue			= io_read,
+		.fail			= io_rw_fail,
 	},
 	[IORING_OP_WRITE_FIXED] = {
 		.needs_file		= 1,
@@ -119,6 +122,7 @@ const struct io_op_def io_op_defs[] = {
 		.name			= "WRITE_FIXED",
 		.prep			= io_prep_rw,
 		.issue			= io_write,
+		.fail			= io_rw_fail,
 	},
 	[IORING_OP_POLL_ADD] = {
 		.needs_file		= 1,
@@ -273,6 +277,7 @@ const struct io_op_def io_op_defs[] = {
 		.name			= "READ",
 		.prep			= io_prep_rw,
 		.issue			= io_read,
+		.fail			= io_rw_fail,
 	},
 	[IORING_OP_WRITE] = {
 		.needs_file		= 1,
@@ -287,6 +292,7 @@ const struct io_op_def io_op_defs[] = {
 		.name			= "WRITE",
 		.prep			= io_prep_rw,
 		.issue			= io_write,
+		.fail			= io_rw_fail,
 	},
 	[IORING_OP_FADVISE] = {
 		.needs_file		= 1,
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -984,6 +984,14 @@ static void io_cqring_ev_posted_iopoll(s
 		io_cqring_wake(ctx);
 }
 
+void io_rw_fail(struct io_kiocb *req)
+{
+	int res;
+
+	res = io_fixup_rw_res(req, req->cqe.res);
+	io_req_set_res(req, res, req->cqe.flags);
+}
+
 int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin)
 {
 	struct io_wq_work_node *pos, *start, *prev;
--- a/io_uring/rw.h
+++ b/io_uring/rw.h
@@ -21,3 +21,4 @@ int io_readv_prep_async(struct io_kiocb
 int io_write(struct io_kiocb *req, unsigned int issue_flags);
 int io_writev_prep_async(struct io_kiocb *req);
 void io_readv_writev_cleanup(struct io_kiocb *req);
+void io_rw_fail(struct io_kiocb *req);