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authorXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>2020-04-08 22:29:58 +0800
committerJens Axboe <axboe@kernel.dk>2020-04-08 09:23:42 -0600
commit45097daea2f4e89bdb1c98359f78d0d6feb8e5c8 (patch)
tree97a91059f9973494c0a08c2e3923ffe69dff336e /fs
parent08a1d26eb894a9dcf79f674558a284ad1ffef517 (diff)
downloadlinux-45097daea2f4e89bdb1c98359f78d0d6feb8e5c8.tar.bz2
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 <xiaoguang.wang@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs')
-rw-r--r--fs/io_uring.c5
1 files changed, 3 insertions, 2 deletions
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;
}