net: remove deprecated syststamp timestamp

The SO_TIMESTAMPING API defines three types of timestamps: software,
hardware in raw format (hwtstamp) and hardware converted to system
format (syststamp). The last has been deprecated in favor of combining
hwtstamp with a PTP clock driver. There are no active users in the
kernel.

The option was device driver dependent. If set, but without hardware
support, the correct behavior is to return zero in the relevant field
in the SCM_TIMESTAMPING ancillary message. Without device drivers
implementing the option, this field is effectively always zero.

Remove the internal plumbing to dissuage new drivers from implementing
the feature. Keep the SOF_TIMESTAMPING_SYS_HARDWARE flag, however, to
avoid breaking existing applications that request the timestamp.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/networking/timestamping.txt b/Documentation/networking/timestamping.txt
index 8b4ad809df277f9ac44604f71896bf4e6d51eadb..897f942b976bd61597d5dd49ceb17cf24a0bc70d 100644 (file)
--- a/Documentation/networking/timestamping.txt
+++ b/Documentation/networking/timestamping.txt
@@ -88,15 +88,8 @@ hwtimeraw is the original hardware time stamp. Filled in if
 SOF_TIMESTAMPING_RAW_HARDWARE is set. No assumptions about its
 relation to system time should be made.
 
-hwtimetrans is the hardware time stamp transformed so that it
-corresponds as good as possible to system time. This correlation is
-not perfect; as a consequence, sorting packets received via different
-NICs by their hwtimetrans may differ from the order in which they were
-received. hwtimetrans may be non-monotonic even for the same NIC.
-Filled in if SOF_TIMESTAMPING_SYS_HARDWARE is set. Requires support
-by the network device and will be empty without that support. This
-field is DEPRECATED. Only one driver computes this value. New device
-drivers must leave this zero. Instead, they can expose the hardware
+hwtimetrans is always zero. This field is deprecated. It used to hold
+hw timestamps converted to system time. Instead, expose the hardware
 clock device on the NIC directly as a HW PTP clock source, to allow
 time conversion in userspace and optionally synchronize system time
 with a userspace PTP stack such as linuxptp. For the PTP clock API,
@@ -191,7 +184,6 @@ struct skb_shared_hwtstamps {
         * since arbitrary point in time
         */
        ktime_t hwtstamp;
-       ktime_t syststamp; /* hwtstamp transformed to system time base */
 };
 
 Time stamps for outgoing packets are to be generated as follows:

diff --git a/Documentation/networking/timestamping/timestamping.c b/Documentation/networking/timestamping/timestamping.c
index 8ba82bfe6a33c57d54adcde8d7c3e1977926d565..5cdfd743447b72b465ffbff763a4981f3126a02f 100644 (file)
--- a/Documentation/networking/timestamping/timestamping.c
+++ b/Documentation/networking/timestamping/timestamping.c
@@ -76,7 +76,6 @@ static void usage(const char *error)
               "  SOF_TIMESTAMPING_RX_HARDWARE - hardware time stamping of incoming packets\n"
               "  SOF_TIMESTAMPING_RX_SOFTWARE - software fallback for incoming packets\n"
               "  SOF_TIMESTAMPING_SOFTWARE - request reporting of software time stamps\n"
-              "  SOF_TIMESTAMPING_SYS_HARDWARE - request reporting of transformed HW time stamps\n"
               "  SOF_TIMESTAMPING_RAW_HARDWARE - request reporting of raw HW time stamps\n"
               "  SIOCGSTAMP - check last socket time stamp\n"
               "  SIOCGSTAMPNS - more accurate socket time stamp\n");
@@ -202,9 +201,7 @@ static void printpacket(struct msghdr *msg, int res,
                                       (long)stamp->tv_sec,
                                       (long)stamp->tv_nsec);
                                stamp++;
-                               printf("HW transformed %ld.%09ld ",
-                                      (long)stamp->tv_sec,
-                                      (long)stamp->tv_nsec);
+                               /* skip deprecated HW transformed */
                                stamp++;
                                printf("HW raw %ld.%09ld",
                                       (long)stamp->tv_sec,
@@ -361,8 +358,6 @@ int main(int argc, char **argv)
                        so_timestamping_flags |= SOF_TIMESTAMPING_RX_SOFTWARE;
                else if (!strcasecmp(argv[i], "SOF_TIMESTAMPING_SOFTWARE"))
                        so_timestamping_flags |= SOF_TIMESTAMPING_SOFTWARE;
-               else if (!strcasecmp(argv[i], "SOF_TIMESTAMPING_SYS_HARDWARE"))
-                       so_timestamping_flags |= SOF_TIMESTAMPING_SYS_HARDWARE;
                else if (!strcasecmp(argv[i], "SOF_TIMESTAMPING_RAW_HARDWARE"))
                        so_timestamping_flags |= SOF_TIMESTAMPING_RAW_HARDWARE;
                else

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index b613557132b90154d2a1dd7971b0fcf60d3d1aaa..281deced7469e5ff6c46ebae46c8138cfd35fada 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -210,20 +210,9 @@ static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
  * struct skb_shared_hwtstamps - hardware time stamps
  * @hwtstamp:  hardware time stamp transformed into duration
  *             since arbitrary point in time
- * @syststamp: hwtstamp transformed to system time base (deprecated)
  *
  * Software time stamps generated by ktime_get_real() are stored in
- * skb->tstamp. The relation between the different kinds of time
- * stamps is as follows:
- *
- * syststamp and tstamp can be compared against each other in
- * arbitrary combinations.  The accuracy of a
- * syststamp/tstamp/"syststamp from other device" comparison is
- * limited by the accuracy of the transformation into system time
- * base. This depends on the device driver and its underlying
- * hardware. The syststamp implementation is deprecated in favor
- * of hwtstamps and hw PTP clock sources exposed directly to
- * userspace.
+ * skb->tstamp.
  *
  * hwtstamps can only be compared against other hwtstamps from
  * the same device.
@@ -233,7 +222,6 @@ static inline void skb_frag_size_sub(skb_frag_t *frag, int delta)
  */
 struct skb_shared_hwtstamps {
        ktime_t hwtstamp;
-       ktime_t syststamp;
 };
 
 /* Definitions for tx_flags in struct skb_shared_info */

diff --git a/include/net/sock.h b/include/net/sock.h
index 720773304a85d45b28e3a3b3ffff1a7e998247c5..b91c8868ab8d66e173f7695d36e2c6aef1ce75dc 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -707,7 +707,6 @@ enum sock_flags {
        SOCK_TIMESTAMPING_RX_SOFTWARE,  /* %SOF_TIMESTAMPING_RX_SOFTWARE */
        SOCK_TIMESTAMPING_SOFTWARE,     /* %SOF_TIMESTAMPING_SOFTWARE */
        SOCK_TIMESTAMPING_RAW_HARDWARE, /* %SOF_TIMESTAMPING_RAW_HARDWARE */
-       SOCK_TIMESTAMPING_SYS_HARDWARE, /* %SOF_TIMESTAMPING_SYS_HARDWARE */
        SOCK_FASYNC, /* fasync() active */
        SOCK_RXQ_OVFL,
        SOCK_ZEROCOPY, /* buffers from userspace */
@@ -2166,16 +2165,13 @@ sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
         * - software time stamp available and wanted
         *   (SOCK_TIMESTAMPING_SOFTWARE)
         * - hardware time stamps available and wanted
-        *   (SOCK_TIMESTAMPING_SYS_HARDWARE or
-        *   SOCK_TIMESTAMPING_RAW_HARDWARE)
+        *   SOCK_TIMESTAMPING_RAW_HARDWARE
         */
        if (sock_flag(sk, SOCK_RCVTSTAMP) ||
            sock_flag(sk, SOCK_TIMESTAMPING_RX_SOFTWARE) ||
            (kt.tv64 && sock_flag(sk, SOCK_TIMESTAMPING_SOFTWARE)) ||
            (hwtstamps->hwtstamp.tv64 &&
-            sock_flag(sk, SOCK_TIMESTAMPING_RAW_HARDWARE)) ||
-           (hwtstamps->syststamp.tv64 &&
-            sock_flag(sk, SOCK_TIMESTAMPING_SYS_HARDWARE)))
+            sock_flag(sk, SOCK_TIMESTAMPING_RAW_HARDWARE)))
                __sock_recv_timestamp(msg, sk, skb);
        else
                sk->sk_stamp = kt;
@@ -2193,8 +2189,7 @@ static inline void sock_recv_ts_and_drops(struct msghdr *msg, struct sock *sk,
 #define FLAGS_TS_OR_DROPS ((1UL << SOCK_RXQ_OVFL)                      | \
                           (1UL << SOCK_RCVTSTAMP)                      | \
                           (1UL << SOCK_TIMESTAMPING_SOFTWARE)          | \
-                          (1UL << SOCK_TIMESTAMPING_RAW_HARDWARE)      | \
-                          (1UL << SOCK_TIMESTAMPING_SYS_HARDWARE))
+                          (1UL << SOCK_TIMESTAMPING_RAW_HARDWARE))
 
        if (sk->sk_flags & FLAGS_TS_OR_DROPS)
                __sock_recv_ts_and_drops(msg, sk, skb);

diff --git a/net/core/sock.c b/net/core/sock.c
index ca9b65199d281342f5ae4671ddd3a44476083319..134291d73fcd2852b864663d96e5f142b6fd7d31 100644 (file)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -862,8 +862,6 @@ set_rcvbuf:
                                               (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE));
                sock_valbool_flag(sk, SOCK_TIMESTAMPING_SOFTWARE,
                                  val & SOF_TIMESTAMPING_SOFTWARE);
-               sock_valbool_flag(sk, SOCK_TIMESTAMPING_SYS_HARDWARE,
-                                 val & SOF_TIMESTAMPING_SYS_HARDWARE);
                sock_valbool_flag(sk, SOCK_TIMESTAMPING_RAW_HARDWARE,
                                  val & SOF_TIMESTAMPING_RAW_HARDWARE);
                break;
@@ -1102,8 +1100,6 @@ int sock_getsockopt(struct socket *sock, int level, int optname,
                        v.val |= SOF_TIMESTAMPING_RX_SOFTWARE;
                if (sock_flag(sk, SOCK_TIMESTAMPING_SOFTWARE))
                        v.val |= SOF_TIMESTAMPING_SOFTWARE;
-               if (sock_flag(sk, SOCK_TIMESTAMPING_SYS_HARDWARE))
-                       v.val |= SOF_TIMESTAMPING_SYS_HARDWARE;
                if (sock_flag(sk, SOCK_TIMESTAMPING_RAW_HARDWARE))
                        v.val |= SOF_TIMESTAMPING_RAW_HARDWARE;
                break;

diff --git a/net/socket.c b/net/socket.c
index abf56b2a14f9bc0a9f7c83fbcabaa2e97b3eca37..d8222c0250618a64197d5a4aba89313859b8d4eb 100644 (file)
--- a/net/socket.c
+++ b/net/socket.c
@@ -725,14 +725,10 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk,
        if (sock_flag(sk, SOCK_TIMESTAMPING_SOFTWARE) &&
            ktime_to_timespec_cond(skb->tstamp, ts + 0))
                empty = 0;
-       if (shhwtstamps) {
-               if (sock_flag(sk, SOCK_TIMESTAMPING_SYS_HARDWARE) &&
-                   ktime_to_timespec_cond(shhwtstamps->syststamp, ts + 1))
-                       empty = 0;
-               if (sock_flag(sk, SOCK_TIMESTAMPING_RAW_HARDWARE) &&
-                   ktime_to_timespec_cond(shhwtstamps->hwtstamp, ts + 2))
-                       empty = 0;
-       }
+       if (shhwtstamps &&
+           sock_flag(sk, SOCK_TIMESTAMPING_RAW_HARDWARE) &&
+           ktime_to_timespec_cond(shhwtstamps->hwtstamp, ts + 2))
+               empty = 0;
        if (!empty)
                put_cmsg(msg, SOL_SOCKET,
                         SCM_TIMESTAMPING, sizeof(ts), &ts);