From 45097daea2f4e89bdb1c98359f78d0d6feb8e5c8 Mon Sep 17 00:00:00 2001 From: Xiaoguang Wang Date: Wed, 8 Apr 2020 22:29:58 +0800 Subject: io_uring: do not always copy iovec in io_req_map_rw() 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 Signed-off-by: Jens Axboe --- fs/io_uring.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'fs') diff --git a/fs/io_uring.c b/fs/io_uring.c index e71aa42e102a..b06188a50af4 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; } -- cgit v1.2.3