[PATCH v3 47/55] dlm: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage
From: David Howells <dhowells@redhat.com>
Date: 2023-03-31 16:18:58
Also in:
linux-fsdevel, linux-mm, lkml
Subsystem:
distributed lock manager (dlm), filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Aring, David Teigland, Alexander Viro, Christian Brauner, Linus Torvalds
When transmitting data, call down a layer using a single sendmsg with MSG_SPLICE_PAGES to indicate that content should be spliced rather using sendpage. This allows ->sendpage() to be replaced by something that can handle multiple multipage folios in a single transaction. Signed-off-by: David Howells <dhowells@redhat.com> cc: Christine Caulfield <redacted> cc: David Teigland <teigland@redhat.com> 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: Jens Axboe <axboe@kernel.dk> cc: Matthew Wilcox <willy@infradead.org> cc: cluster-devel@redhat.com cc: netdev@vger.kernel.org --- fs/dlm/lowcomms.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index a9b14f81d655..9c0c691b6106 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c@@ -1394,8 +1394,11 @@ int dlm_lowcomms_resend_msg(struct dlm_msg *msg) /* Send a message */ static int send_to_sock(struct connection *con) { - const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL; struct writequeue_entry *e; + struct bio_vec bvec; + struct msghdr msg = { + .msg_flags = MSG_SPLICE_PAGES | MSG_DONTWAIT | MSG_NOSIGNAL, + }; int len, offset, ret; spin_lock_bh(&con->writequeue_lock);
@@ -1411,8 +1414,9 @@ static int send_to_sock(struct connection *con) WARN_ON_ONCE(len == 0 && e->users == 0); spin_unlock_bh(&con->writequeue_lock); - ret = kernel_sendpage(con->sock, e->page, offset, len, - msg_flags); + bvec_set_page(&bvec, e->page, len, offset); + iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, len); + ret = sock_sendmsg(con->sock, &msg); trace_dlm_send(con->nodeid, ret); if (ret == -EAGAIN || ret == 0) { lock_sock(con->sock->sk);