[PATCH 2/3] io_uring: ensure reads re-import for selected buffers

[Jens Axboe <axboe@kernel.dk>]

If we drop buffers between scheduling a retry, then we need to re-import
when we start the request again.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 fs/io_uring.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 4d8366bc226f..584b36dcd0aa 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3737,6 +3737,16 @@ static int io_read(struct io_kiocb *req, unsigned int issue_flags)
 		if (unlikely(ret < 0))
 			return ret;
 	} else {
+		/*
+		 * Safe and required to re-import if we're using provided
+		 * buffers, as we dropped the selected one before retry.
+		 */
+		if (req->flags & REQ_F_BUFFER_SELECT) {
+			ret = io_import_iovec(READ, req, &iovec, s, issue_flags);
+			if (unlikely(ret < 0))
+				return ret;
+		}
+
 		rw = req->async_data;
 		s = &rw->s;
 		/*
-- 
2.35.1