Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | From | David Howells <> | Subject | [RFC PATCH 3/3] net: Declare MSG_SPLICE_PAGES internal sendmsg() flag | Date | Wed, 22 Mar 2023 13:56:12 +0000 |
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Declare MSG_SPLICE_PAGES, an internal sendmsg() flag, that hints to a network protocol that it should splice pages from the source iterator rather than copying the data if it can. This is set in msg->msg_kflags, not msg->msg_flags, thereby isolating it from the UAPI.
This is intended as a replacement for the ->sendpage() op, allowing a way to splice in several multipage folios in one go.
Signed-off-by: David Howells <dhowells@redhat.com> cc: Willem de Bruijn <willemdebruijn.kernel@gmail.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: netdev@vger.kernel.org --- include/linux/socket.h | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/include/linux/socket.h b/include/linux/socket.h index 13c3a237b9c9..229f54484d3c 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -72,6 +72,7 @@ struct msghdr { bool msg_control_is_user : 1; bool msg_get_inq : 1;/* return INQ after receive */ unsigned int msg_flags; /* flags on received message */ + unsigned int msg_kflags; /* Kernel internal flags */ __kernel_size_t msg_controllen; /* ancillary data buffer length */ struct kiocb *msg_iocb; /* ptr to iocb for async requests */ struct ubuf_info *msg_ubuf; @@ -337,6 +338,8 @@ struct ucred { #define MSG_CMSG_COMPAT 0 /* We never have 32 bit fixups */ #endif +/* Flags for msghdr::msg_kflags (all internal to the kernel) */ +#define MSG_SPLICE_PAGES 0x00000001 /* Splice the pages from the iterator in sendmsg() */ /* Setsockoptions(2) level. Thanks to BSD these must match IPPROTO_xxx */ #define SOL_IP 0
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