[PATCH net-next v4 10/15] drbd: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage()
From: David Howells <dhowells@redhat.com>
Date: 2023-06-23 11:46:58
Also in:
linux-block, linux-mm, lkml
Subsystem:
block layer, drbd driver, the rest · Maintainers:
Jens Axboe, Philipp Reisner, Lars Ellenberg, Christoph Böhmwalder, Linus Torvalds
Use sendmsg() conditionally with MSG_SPLICE_PAGES in _drbd_send_page()
rather than calling sendpage() or _drbd_no_send_page().
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Philipp Reisner <philipp.reisner@linbit.com>
cc: Lars Ellenberg <lars.ellenberg@linbit.com>
cc: "Christoph Böhmwalder" <christoph.boehmwalder@linbit.com>
cc: Jens Axboe <axboe@kernel.dk>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: drbd-dev@lists.linbit.com
cc: linux-block@vger.kernel.org
cc: netdev@vger.kernel.org
---
Notes:
ver #4)
- Don't look at msg.msg_iter after calling sendmsg. There's no guarantee
it has changed.
ver #2)
- Wrap lines at 80.
drivers/block/drbd/drbd_main.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 83987e7a5ef2..ea82d6733313 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c@@ -1540,6 +1540,8 @@ static int _drbd_send_page(struct drbd_peer_device *peer_device, struct page *pa int offset, size_t size, unsigned msg_flags) { struct socket *socket = peer_device->connection->data.socket; + struct msghdr msg = { .msg_flags = msg_flags, }; + struct bio_vec bvec; int len = size; int err = -EIO;
@@ -1549,15 +1551,17 @@ static int _drbd_send_page(struct drbd_peer_device *peer_device, struct page *pa * put_page(); and would cause either a VM_BUG directly, or * __page_cache_release a page that would actually still be referenced * by someone, leading to some obscure delayed Oops somewhere else. */ - if (drbd_disable_sendpage || !sendpage_ok(page)) - return _drbd_no_send_page(peer_device, page, offset, size, msg_flags); + if (!drbd_disable_sendpage && sendpage_ok(page)) + msg.msg_flags |= MSG_NOSIGNAL | MSG_SPLICE_PAGES; - msg_flags |= MSG_NOSIGNAL; drbd_update_congested(peer_device->connection); do { int sent; - sent = socket->ops->sendpage(socket, page, offset, len, msg_flags); + bvec_set_page(&bvec, page, offset, len); + iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, len); + + sent = sock_sendmsg(socket, &msg); if (sent <= 0) { if (sent == -EAGAIN) { if (we_should_drop_the_connection(peer_device->connection, socket))