Hi Mat,
-----Original Message----- From: Mat Martineau mathew.j.martineau@linux.intel.com Sent: 2021年6月16日 9:01 To: Y.b. Lu yangbo.lu@nxp.com Cc: netdev@vger.kernel.org; linux-kernel@vger.kernel.org; linux-kselftest@vger.kernel.org; mptcp@lists.linux.dev; Richard Cochran richardcochran@gmail.com; David S . Miller davem@davemloft.net; Jakub Kicinski kuba@kernel.org; Matthieu Baerts matthieu.baerts@tessares.net; Shuah Khan shuah@kernel.org; Michal Kubecek mkubecek@suse.cz; Florian Fainelli f.fainelli@gmail.com; Andrew Lunn andrew@lunn.ch; Rui Sousa rui.sousa@nxp.com; Sebastien Laveze sebastien.laveze@nxp.com; Florian Westphal fw@strlen.de Subject: Re: [net-next, v3, 07/10] net: sock: extend SO_TIMESTAMPING for PHC binding
On Tue, 15 Jun 2021, Yangbo Lu wrote:
Since PTP virtual clock support is added, there can be several PTP virtual clocks based on one PTP physical clock for timestamping.
This patch is to extend SO_TIMESTAMPING API to support PHC (PTP Hardware Clock) binding by adding a new flag SOF_TIMESTAMPING_BIND_PHC. When PTP virtual clocks are in use, user space can configure to bind one for timestamping, but PTP physical clock is not supported and not needed to bind.
This patch is preparation for timestamp conversion from raw timestamp to a specific PTP virtual clock time in core net.
Signed-off-by: Yangbo Lu yangbo.lu@nxp.com
Changes for v3:
- Added this patch.
include/net/sock.h | 8 +++- include/uapi/linux/net_tstamp.h | 17 ++++++++- net/core/sock.c | 65
+++++++++++++++++++++++++++++++--
net/ethtool/common.c | 1 + net/mptcp/sockopt.c | 10 +++-- 5 files changed, 91 insertions(+), 10 deletions(-)
[...]
@@ -166,7 +169,7 @@ static int
mptcp_setsockopt_sol_socket_tstamp(struct mptcp_sock *msk, int optnam
break; case SO_TIMESTAMPING_NEW: case SO_TIMESTAMPING_OLD:
sock_set_timestamping(sk, optname, val);
sock_set_timestamping(sk, optname, val, optval, optlen);This is inside a loop, so in cases where optlen == sizeof(struct so_timestamping) this will end up re-copying the structure from userspace one extra time for each MPTCP subflow: once for the MPTCP socket, plus one time for each of the TCP subflows that are grouped under this MPTCP connection.
Given that the extra copies only happen when using the extended bind_phc option, it's not a huge cost. But sock_set_timestamping() was written to avoid the extra copies for 'int' sized options, and if that was worth the effort then the larger so_timestamping structure could be copied (once) before the sock_set_timestamping() call and passed in.
I see now... Let me pass so_timestamping structure in to avoid re-copying from userspace.
break; }@@ -207,7 +210,8 @@ static int mptcp_setsockopt_sol_socket_int(struct
mptcp_sock *msk, int optname,
case SO_TIMESTAMPNS_NEW: case SO_TIMESTAMPING_OLD: case SO_TIMESTAMPING_NEW:
return mptcp_setsockopt_sol_socket_tstamp(msk, optname, val);
return mptcp_setsockopt_sol_socket_tstamp(msk, optname, val,optval, optlen);Rather than modifying mptcp_setsockopt_sol_socket_int(), I suggest adding a mptcp_setsockopt_sol_socket_timestamping() helper function that can handle the special copying for so_timestamping.
Thank you. Let me do this in next version.
}
return -ENOPROTOOPT;
2.25.1
-- Mat Martineau Intel