In io_read_prep() or io_write_prep(), io_req_map_rw() takes
struct io_async_rw's fast_iov as argument to call io_import_iovec(),
and if io_import_iovec() uses struct io_async_rw's fast_iov as
valid iovec array, later indeed io_req_map_rw() does not need
to do the memcpy operation, because they are same pointers.
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@xxxxxxxxxxxxxxxxx>
---
fs/io_uring.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6ac830b2b4fb..5eeac5b8ccc6 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2493,8 +2493,9 @@ static void io_req_map_rw(struct io_kiocb *req, ssize_t io_size,
req->io->rw.iov = iovec;
if (!req->io->rw.iov) {
req->io->rw.iov = req->io->rw.fast_iov;
- memcpy(req->io->rw.iov, fast_iov,
- sizeof(struct iovec) * iter->nr_segs);
+ if (req->io->rw.iov != fast_iov)
+ memcpy(req->io->rw.iov, fast_iov,
+ sizeof(struct iovec) * iter->nr_segs);
} else {
req->flags |= REQ_F_NEED_CLEANUP;
}
--
2.17.2
