* [PATCH] io_uring: do not always copy iovec in io_req_map_rw()
@ 2020-04-08 14:29 Xiaoguang Wang
2020-04-08 15:24 ` Jens Axboe
0 siblings, 1 reply; 2+ messages in thread
From: Xiaoguang Wang @ 2020-04-08 14:29 UTC (permalink / raw)
To: io-uring; +Cc: axboe, joseph.qi, Xiaoguang Wang
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 <[email protected]>
---
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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] io_uring: do not always copy iovec in io_req_map_rw()
2020-04-08 14:29 [PATCH] io_uring: do not always copy iovec in io_req_map_rw() Xiaoguang Wang
@ 2020-04-08 15:24 ` Jens Axboe
0 siblings, 0 replies; 2+ messages in thread
From: Jens Axboe @ 2020-04-08 15:24 UTC (permalink / raw)
To: Xiaoguang Wang, io-uring; +Cc: joseph.qi
On 4/8/20 7:29 AM, Xiaoguang Wang wrote:
> 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.
Applied, thanks.
--
Jens Axboe
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2020-04-08 15:24 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2020-04-08 14:29 [PATCH] io_uring: do not always copy iovec in io_req_map_rw() Xiaoguang Wang
2020-04-08 15:24 ` Jens Axboe
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox