[PATCH] io_uring/rw: fix missing ERESTARTSYS conversion in read paths

[Yitang Yang <yi1tang.yang@gmail.com>]

Both read and write may receive internal restart error codes from
the filesystem layer and should be converted to -EINTR. However,
when multishot read support was added, the error code normalization
was lost for both io_read() and io_read_mshot().

Extract the conversion into io_fixup_restart_res() and apply it
in all three locations: io_rw_done(), io_read(), and io_read_mshot().

Fixes: a08d195b586a ("io_uring/rw: split io_read() into a helper")
Signed-off-by: Yitang Yang <yi1tang.yang@gmail.com>
---
 io_uring/rw.c | 38 ++++++++++++++++++++++++--------------
 1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/io_uring/rw.c b/io_uring/rw.c
index 63b6519e498c..e505479e3773 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -615,6 +615,24 @@ static void io_complete_rw_iopoll(struct kiocb *kiocb, long res)
 	smp_store_release(&req->iopoll_completed, 1);
 }
 
+static inline ssize_t io_fixup_restart_res(ssize_t ret)
+{
+	switch (ret) {
+	case -ERESTARTSYS:
+	case -ERESTARTNOINTR:
+	case -ERESTARTNOHAND:
+	case -ERESTART_RESTARTBLOCK:
+		/*
+		 * We can't just restart the syscall, since previously
+		 * submitted sqes may already be in progress. Just fail
+		 * this IO with EINTR.
+		 */
+		return -EINTR;
+	default:
+		return ret;
+	}
+}
+
 static inline void io_rw_done(struct io_kiocb *req, ssize_t ret)
 {
 	struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
@@ -625,19 +643,7 @@ static inline void io_rw_done(struct io_kiocb *req, ssize_t ret)
 
 	/* transform internal restart error codes */
 	if (unlikely(ret < 0)) {
-		switch (ret) {
-		case -ERESTARTSYS:
-		case -ERESTARTNOINTR:
-		case -ERESTARTNOHAND:
-		case -ERESTART_RESTARTBLOCK:
-			/*
-			 * We can't just restart the syscall, since previously
-			 * submitted sqes may already be in progress. Just fail
-			 * this IO with EINTR.
-			 */
-			ret = -EINTR;
-			break;
-		}
+		ret = io_fixup_restart_res(ret);
 	}
 
 	if (req->flags & REQ_F_IOPOLL)
@@ -1034,6 +1040,8 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags)
 
 	if (req->flags & REQ_F_BUFFERS_COMMIT)
 		io_kbuf_recycle(req, sel.buf_list, issue_flags);
+
+	ret = io_fixup_restart_res(ret);
 	return ret;
 }
 
@@ -1068,8 +1076,10 @@ int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags)
 		return IOU_RETRY;
 	} else if (ret <= 0) {
 		io_kbuf_recycle(req, sel.buf_list, issue_flags);
-		if (ret < 0)
+		if (ret < 0) {
+			ret = io_fixup_restart_res(ret);
 			req_set_fail(req);
+		}
 	} else if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
 		cflags = io_put_kbuf(req, ret, sel.buf_list);
 	} else {
-- 
2.43.0