[PATCH 6.1 295/609] io_uring/rw: fix missing ERESTARTSYS conversion in read paths

6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Yitang Yang <[email protected]>

Commit ab05caca123c6d0b41850b7c05b246e4dca4a770 upstream.

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")
Cc: [email protected]
Signed-off-by: Yitang Yang <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
 io_uring/rw.c | 28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/io_uring/rw.c b/io_uring/rw.c
index b75f62dccce6..cbd3ee9a9373 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -129,27 +129,37 @@ void io_readv_writev_cleanup(struct io_kiocb *req)
 	kfree(io->free_iovec);
 }
 
-static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
+static inline ssize_t io_fixup_restart_res(ssize_t ret)
 {
 	switch (ret) {
-	case -EIOCBQUEUED:
-		break;
 	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.
+		 * submitted sqes may already be in progress. Just fail
+		 * this IO with EINTR.
 		 */
-		ret = -EINTR;
-		fallthrough;
+		return -EINTR;
 	default:
-		kiocb->ki_complete(kiocb, ret);
+		return ret;
 	}
 }
 
+static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
+{
+	/* IO was queued async, completion will happen later */
+	if (ret == -EIOCBQUEUED)
+		return;
+
+	/* transform internal restart error codes */
+	if (unlikely(ret < 0))
+		ret = io_fixup_restart_res(ret);
+
+	kiocb->ki_complete(kiocb, ret);
+}
+
 static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req)
 {
 	struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw);
@@ -854,7 +864,7 @@ int io_read(struct io_kiocb *req, unsigned int issue_flags)
 	if (ret >= 0)
 		return kiocb_done(req, ret, issue_flags);
 
-	return ret;
+	return io_fixup_restart_res(ret);
 }
 
 static bool io_kiocb_start_write(struct io_kiocb *req, struct kiocb *kiocb)
-- 
2.53.0