[ovs-dev] [mii 1/2] netdev: Take responsibility for polling MII registers.

Ethan Jackson ethan at nicira.com
Fri May 20 00:10:20 UTC 2011


This patch moves miimon logic from the bond module to netdev-linux.
This greatly simplifies the bonding code while adding minimal
complexity to netdev-linux.  The bonding code is so high level, it
really has no business worrying about how precisely slave status is
determined.
---
 lib/bond.c            |  101 ++++--------------------------------------------
 lib/bond.h            |   11 -----
 lib/netdev-linux.c    |  100 ++++++++++++++++++++++++++++++++++++++++++++----
 lib/netdev-provider.h |   14 ++++--
 lib/netdev.c          |   39 +++++++------------
 lib/netdev.h          |    2 +-
 vswitchd/bridge.c     |   24 +++++++-----
 7 files changed, 138 insertions(+), 153 deletions(-)

diff --git a/lib/bond.c b/lib/bond.c
index 5cb218d..f5d0110 100644
--- a/lib/bond.c
+++ b/lib/bond.c
@@ -105,10 +105,7 @@ struct bond {
     tag_type stb_tag;               /* Tag associated with this bond. */
 
     /* Monitoring. */
-    enum bond_detect_mode detect;     /* Link status mode, one of BLSM_*. */
     struct netdev_monitor *monitor;   /* detect == BLSM_CARRIER only. */
-    long long int miimon_interval;    /* Miimon status refresh interval. */
-    long long int miimon_next_update; /* Time of next miimon update. */
 
     /* Legacy compatibility. */
     long long int next_fake_iface_update; /* LLONG_MAX if disabled. */
@@ -123,7 +120,6 @@ static struct hmap all_bonds = HMAP_INITIALIZER(&all_bonds);
 
 static void bond_entry_reset(struct bond *);
 static struct bond_slave *bond_slave_lookup(struct bond *, const void *slave_);
-static bool bond_is_link_up(struct bond *, struct netdev *);
 static void bond_enable_slave(struct bond_slave *, bool enable,
                               struct tag_set *);
 static void bond_link_status_update(struct bond_slave *, struct tag_set *);
@@ -178,34 +174,6 @@ bond_mode_to_string(enum bond_mode balance) {
     NOT_REACHED();
 }
 
-/* Attempts to parse 's' as the name of a bond link status detection mode.  If
- * successful, stores the mode in '*detect' and returns true.  Otherwise
- * returns false without modifying '*detect'. */
-bool
-bond_detect_mode_from_string(enum bond_detect_mode *detect, const char *s)
-{
-    if (!strcmp(s, bond_detect_mode_to_string(BLSM_CARRIER))) {
-        *detect = BLSM_CARRIER;
-    } else if (!strcmp(s, bond_detect_mode_to_string(BLSM_MIIMON))) {
-        *detect = BLSM_MIIMON;
-    } else {
-        return false;
-    }
-    return true;
-}
-
-/* Returns a string representing 'detect'. */
-const char *
-bond_detect_mode_to_string(enum bond_detect_mode detect)
-{
-    switch (detect) {
-    case BLSM_CARRIER:
-        return "carrier";
-    case BLSM_MIIMON:
-        return "miimon";
-    }
-    NOT_REACHED();
-}
 
 /* Creates and returns a new bond whose configuration is initially taken from
  * 's'.
@@ -221,8 +189,8 @@ bond_create(const struct bond_settings *s)
     hmap_init(&bond->slaves);
     bond->no_slaves_tag = tag_create_random();
     bond->stb_tag = tag_create_random();
-    bond->miimon_next_update = LLONG_MAX;
     bond->next_fake_iface_update = LLONG_MAX;
+    bond->monitor = netdev_monitor_create();
 
     bond_reconfigure(bond, s);
 
@@ -282,8 +250,6 @@ bond_reconfigure(struct bond *bond, const struct bond_settings *s)
         hmap_insert(&all_bonds, &bond->hmap_node, hash_string(bond->name, 0));
     }
 
-    bond->detect = s->detect;
-    bond->miimon_interval = s->miimon_interval;
     bond->updelay = s->up_delay;
     bond->downdelay = s->down_delay;
     bond->rebalance_interval = s->rebalance_interval;
@@ -298,25 +264,6 @@ bond_reconfigure(struct bond *bond, const struct bond_settings *s)
         revalidate = true;
     }
 
-    if (bond->detect == BLSM_CARRIER) {
-        struct bond_slave *slave;
-
-        if (!bond->monitor) {
-            bond->monitor = netdev_monitor_create();
-        }
-
-        HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
-            netdev_monitor_add(bond->monitor, slave->netdev);
-        }
-    } else {
-        netdev_monitor_destroy(bond->monitor);
-        bond->monitor = NULL;
-
-        if (bond->miimon_next_update == LLONG_MAX) {
-            bond->miimon_next_update = time_msec() + bond->miimon_interval;
-        }
-    }
-
     if (s->fake_iface) {
         if (bond->next_fake_iface_update == LLONG_MAX) {
             bond->next_fake_iface_update = time_msec();
@@ -342,12 +289,10 @@ bond_slave_set_netdev__(struct bond *bond, struct bond_slave *slave,
                         struct netdev *netdev)
 {
     if (slave->netdev != netdev) {
-        if (bond->monitor) {
-            if (slave->netdev) {
-                netdev_monitor_remove(bond->monitor, slave->netdev);
-            }
-            netdev_monitor_add(bond->monitor, netdev);
+        if (slave->netdev) {
+            netdev_monitor_remove(bond->monitor, slave->netdev);
         }
+        netdev_monitor_add(bond->monitor, netdev);
         slave->netdev = netdev;
     }
 }
@@ -378,7 +323,7 @@ bond_slave_register(struct bond *bond, void *slave_, uint32_t stb_id,
         slave->bond = bond;
         slave->aux = slave_;
         slave->delay_expires = LLONG_MAX;
-        slave->up = bond_is_link_up(bond, netdev);
+        slave->up = netdev_get_carrier(netdev);
         slave->name = xstrdup(netdev_get_name(netdev));
         bond->bond_revalidate = true;
 
@@ -425,10 +370,7 @@ bond_slave_unregister(struct bond *bond, const void *slave_)
         return;
     }
 
-    if (bond->monitor) {
-        netdev_monitor_remove(bond->monitor, slave->netdev);
-    }
-
+    netdev_monitor_remove(bond->monitor, slave->netdev);
     bond_enable_slave(slave, false, NULL);
 
     del_active = bond->active_slave == slave;
@@ -478,13 +420,8 @@ bond_run(struct bond *bond, struct tag_set *tags, bool lacp_negotiated)
     bond->lacp_negotiated = lacp_negotiated;
 
     /* Update link status. */
-    if (bond->detect == BLSM_CARRIER
-        || time_msec() >= bond->miimon_next_update)
-    {
-        HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
-            slave->up = bond_is_link_up(bond, slave->netdev);
-        }
-        bond->miimon_next_update = time_msec() + bond->miimon_interval;
+    HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
+        slave->up = netdev_get_carrier(slave->netdev);
     }
 
     if (bond->monitor) {
@@ -536,11 +473,7 @@ bond_wait(struct bond *bond)
 {
     struct bond_slave *slave;
 
-    if (bond->detect == BLSM_CARRIER) {
-        netdev_monitor_poll_wait(bond->monitor);
-    } else {
-        poll_timer_wait_until(bond->miimon_next_update);
-    }
+    netdev_monitor_poll_wait(bond->monitor);
 
     HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
         if (slave->delay_expires != LLONG_MAX) {
@@ -1012,14 +945,6 @@ bond_unixctl_show(struct unixctl_conn *conn,
 
     ds_put_format(&ds, "bond-hash-basis: %"PRIu32"\n", bond->basis);
 
-    ds_put_format(&ds, "bond-detect-mode: %s\n",
-                  bond->monitor ? "carrier" : "miimon");
-
-    if (!bond->monitor) {
-        ds_put_format(&ds, "bond-miimon-interval: %lld\n",
-                      bond->miimon_interval);
-    }
-
     ds_put_format(&ds, "updelay: %d ms\n", bond->updelay);
     ds_put_format(&ds, "downdelay: %d ms\n", bond->downdelay);
 
@@ -1324,14 +1249,6 @@ bond_slave_lookup(struct bond *bond, const void *slave_)
     return NULL;
 }
 
-static bool
-bond_is_link_up(struct bond *bond, struct netdev *netdev)
-{
-    return (bond->detect == BLSM_CARRIER
-            ? netdev_get_carrier(netdev)
-            : netdev_get_miimon(netdev));
-}
-
 static void
 bond_enable_slave(struct bond_slave *slave, bool enable, struct tag_set *tags)
 {
diff --git a/lib/bond.h b/lib/bond.h
index fe58792..56ca5b9 100644
--- a/lib/bond.h
+++ b/lib/bond.h
@@ -38,15 +38,6 @@ enum bond_mode {
 bool bond_mode_from_string(enum bond_mode *, const char *);
 const char *bond_mode_to_string(enum bond_mode);
 
-/* How to detect link status. */
-enum bond_detect_mode {
-    BLSM_CARRIER,               /* Use carrier. */
-    BLSM_MIIMON                 /* Poll MII status. */
-};
-
-bool bond_detect_mode_from_string(enum bond_detect_mode *, const char *);
-const char *bond_detect_mode_to_string(enum bond_detect_mode);
-
 /* Configuration for a bond as a whole. */
 struct bond_settings {
     char *name;                 /* Bond's name, for log messages. */
@@ -57,8 +48,6 @@ struct bond_settings {
     int rebalance_interval;     /* Milliseconds between rebalances. */
 
     /* Link status detection. */
-    enum bond_detect_mode detect; /* BLSM_CARRIER or BLSM_MIIMON. */
-    int miimon_interval;        /* Used only for BLSM_MIIMON. */
     int up_delay;               /* ms before enabling an up slave. */
     int down_delay;             /* ms before disabling a down slave. */
 
diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
index a401c60..79451c7 100644
--- a/lib/netdev-linux.c
+++ b/lib/netdev-linux.c
@@ -68,6 +68,7 @@
 #include "socket-util.h"
 #include "shash.h"
 #include "sset.h"
+#include "timer.h"
 #include "vlog.h"
 
 VLOG_DEFINE_THIS_MODULE(netdev_linux);
@@ -346,6 +347,10 @@ struct netdev_dev_linux {
     struct shash_node *shash_node;
     unsigned int cache_valid;
 
+    bool miimon;                    /* Link status of last poll. */
+    long long int miimon_interval;  /* Miimon Poll rate. Disabled if <= 0. */
+    struct timer miimon_timer;
+
     /* The following are figured out "on demand" only.  They are only valid
      * when the corresponding VALID_* bit in 'cache_valid' is set. */
     int ifindex;
@@ -411,6 +416,9 @@ static int set_etheraddr(const char *netdev_name, int hwaddr_family,
 static int get_stats_via_netlink(int ifindex, struct netdev_stats *stats);
 static int get_stats_via_proc(const char *netdev_name, struct netdev_stats *stats);
 static int af_packet_sock(void);
+static void poll_notify(struct list *);
+static void netdev_linux_miimon_run(void);
+static void netdev_linux_miimon_wait(void);
 
 static bool
 is_netdev_linux_class(const struct netdev_class *netdev_class)
@@ -465,12 +473,14 @@ static void
 netdev_linux_run(void)
 {
     rtnetlink_link_notifier_run();
+    netdev_linux_miimon_run();
 }
 
 static void
 netdev_linux_wait(void)
 {
     rtnetlink_link_notifier_wait();
+    netdev_linux_miimon_wait();
 }
 
 static void
@@ -1004,6 +1014,11 @@ netdev_linux_get_carrier(const struct netdev *netdev_, bool *carrier)
     char *fn = NULL;
     int fd = -1;
 
+    if (netdev_dev->miimon_interval > 0) {
+        *carrier = netdev_dev->miimon;
+        return 0;
+    }
+
     if (!(netdev_dev->cache_valid & VALID_CARRIER)) {
         char line[8];
         int retval;
@@ -1054,36 +1069,34 @@ exit:
 }
 
 static int
-netdev_linux_do_miimon(const struct netdev *netdev, int cmd,
-                       const char *cmd_name, struct mii_ioctl_data *data)
+netdev_linux_do_miimon(const char *name, int cmd, const char *cmd_name,
+                       struct mii_ioctl_data *data)
 {
     struct ifreq ifr;
     int error;
 
     memset(&ifr, 0, sizeof ifr);
     memcpy(&ifr.ifr_data, data, sizeof *data);
-    error = netdev_linux_do_ioctl(netdev_get_name(netdev),
-                                  &ifr, cmd, cmd_name);
+    error = netdev_linux_do_ioctl(name, &ifr, cmd, cmd_name);
     memcpy(data, &ifr.ifr_data, sizeof *data);
 
     return error;
 }
 
 static int
-netdev_linux_get_miimon(const struct netdev *netdev, bool *miimon)
+netdev_linux_get_miimon(const char *name, bool *miimon)
 {
-    const char *name = netdev_get_name(netdev);
     struct mii_ioctl_data data;
     int error;
 
     *miimon = false;
 
     memset(&data, 0, sizeof data);
-    error = netdev_linux_do_miimon(netdev, SIOCGMIIPHY, "SIOCGMIIPHY", &data);
+    error = netdev_linux_do_miimon(name, SIOCGMIIPHY, "SIOCGMIIPHY", &data);
     if (!error) {
         /* data.phy_id is filled out by previous SIOCGMIIPHY miimon call. */
         data.reg_num = MII_BMSR;
-        error = netdev_linux_do_miimon(netdev, SIOCGMIIREG, "SIOCGMIIREG",
+        error = netdev_linux_do_miimon(name, SIOCGMIIREG, "SIOCGMIIREG",
                                        &data);
 
         if (!error) {
@@ -1113,6 +1126,75 @@ netdev_linux_get_miimon(const struct netdev *netdev, bool *miimon)
     return error;
 }
 
+static int
+netdev_linux_set_miimon_interval(struct netdev *netdev_,
+                                 long long int interval)
+{
+    struct netdev_dev_linux *netdev_dev;
+
+    netdev_dev = netdev_dev_linux_cast(netdev_get_dev(netdev_));
+
+    netdev_dev->miimon_interval = interval;
+    if (netdev_dev->miimon_interval > 0) {
+        netdev_dev->miimon_interval = MAX(interval, 100);
+        timer_set_expired(&netdev_dev->miimon_timer);
+    }
+
+    return 0;
+}
+
+static void
+netdev_linux_miimon_run(void)
+{
+    struct shash device_shash;
+    struct shash_node *node;
+
+    shash_init(&device_shash);
+    netdev_dev_get_devices(&netdev_linux_class, &device_shash);
+    SHASH_FOR_EACH (node, &device_shash) {
+        struct netdev_dev_linux *dev = node->data;
+        bool miimon;
+
+        if (dev->miimon_interval <= 0 || !timer_expired(&dev->miimon_timer)) {
+            continue;
+        }
+
+        netdev_linux_get_miimon(dev->netdev_dev.name, &miimon);
+        if (miimon != dev->miimon) {
+            struct list *list;
+
+            dev->miimon = miimon;
+            list = shash_find_data(&netdev_linux_notifiers,
+                                   dev->netdev_dev.name);
+            if (list) {
+                poll_notify(list);
+            }
+        }
+
+        timer_set_duration(&dev->miimon_timer, dev->miimon_interval);
+    }
+
+    shash_destroy(&device_shash);
+}
+
+static void
+netdev_linux_miimon_wait(void)
+{
+    struct shash device_shash;
+    struct shash_node *node;
+
+    shash_init(&device_shash);
+    netdev_dev_get_devices(&netdev_linux_class, &device_shash);
+    SHASH_FOR_EACH (node, &device_shash) {
+        struct netdev_dev_linux *dev = node->data;
+
+        if (dev->miimon_interval > 0) {
+            timer_wait(&dev->miimon_timer);
+        }
+    }
+    shash_destroy(&device_shash);
+}
+
 /* Check whether we can we use RTM_GETLINK to get network device statistics.
  * In pre-2.6.19 kernels, this was only available if wireless extensions were
  * enabled. */
@@ -2265,7 +2347,7 @@ netdev_linux_poll_remove(struct netdev_notifier *notifier_)
     netdev_linux_get_mtu,                                       \
     netdev_linux_get_ifindex,                                   \
     netdev_linux_get_carrier,                                   \
-    netdev_linux_get_miimon,                                    \
+    netdev_linux_set_miimon_interval,                           \
     netdev_linux_get_stats,                                     \
     SET_STATS,                                                  \
                                                                 \
diff --git a/lib/netdev-provider.h b/lib/netdev-provider.h
index 6887e7f..23de420 100644
--- a/lib/netdev-provider.h
+++ b/lib/netdev-provider.h
@@ -263,13 +263,17 @@ struct netdev_class {
      */
     int (*get_carrier)(const struct netdev *netdev, bool *carrier);
 
-    /* Sets 'miimon' to true if 'netdev' is up according to its MII.  If
-     * 'netdev' does not support MII, may fall back to another method or return
-     * EOPNOTSUPP.
+    /* Forces ->get_carrier() to poll 'netdev''s MII registers for link status
+     * instead of checking 'netdev''s carrier.  'netdev''s MII registers will
+     * be polled once ever 'interval' milliseconds.  If 'netdev' does not
+     * support MII, another method may be used as a fallback.  If 'interval' is
+     * less than or equal to zero, reverts ->get_carrier() to its normal
+     * behavior.
      *
-     * This function may be set to null if it would always return EOPNOTSUPP.
+     * Most network devices won't support this feature and will set this
+     * function pointer to NULL, which is equivalent to returning EOPNOTSUPP.
      */
-    int (*get_miimon)(const struct netdev *netdev, bool *miimon);
+    int (*set_miimon_interval)(struct netdev *netdev, long long int interval);
 
     /* Retrieves current device stats for 'netdev' into 'stats'.
      *
diff --git a/lib/netdev.c b/lib/netdev.c
index 01d91db..27ef0c3 100644
--- a/lib/netdev.c
+++ b/lib/netdev.c
@@ -886,32 +886,21 @@ netdev_get_carrier(const struct netdev *netdev)
     return carrier;
 }
 
-/* Returns true if 'netdev' is up according to its MII. */
-bool
-netdev_get_miimon(const struct netdev *netdev)
+/* Attempts to force netdev_get_carrier() to poll 'netdev''s MII registers for
+ * link status instead of checking 'netdev''s carrier.  'netdev''s MII
+ * registers will be polled once ever 'interval' milliseconds.  If 'netdev'
+ * does not support MII, another method may be used as a fallback.  If
+ * 'interval' is less than or equal to zero, reverts netdev_get_carrier() to
+ * its normal behavior.
+ *
+ * Returns 0 if successful, otherwise a positive errno value. */
+int
+netdev_set_miimon_interval(struct netdev *netdev, long long int interval)
 {
-    int error;
-    enum netdev_flags flags;
-    bool miimon;
-
-    netdev_get_flags(netdev, &flags);
-    if (!(flags & NETDEV_UP)) {
-        return false;
-    }
-
-    if (!netdev_get_dev(netdev)->netdev_class->get_miimon) {
-        return true;
-    }
-
-    error = netdev_get_dev(netdev)->netdev_class->get_miimon(netdev, &miimon);
-
-    if (error) {
-        VLOG_DBG("%s: failed to get network device MII status, assuming "
-                 "down: %s", netdev_get_name(netdev), strerror(error));
-        miimon = false;
-    }
-
-    return miimon;
+    struct netdev_dev *netdev_dev = netdev_get_dev(netdev);
+    return (netdev_dev->netdev_class->set_miimon_interval
+            ? netdev_dev->netdev_class->set_miimon_interval(netdev, interval)
+            : EOPNOTSUPP);
 }
 
 /* Retrieves current device stats for 'netdev'. */
diff --git a/lib/netdev.h b/lib/netdev.h
index 81d74ae..cc81e6c 100644
--- a/lib/netdev.h
+++ b/lib/netdev.h
@@ -130,7 +130,7 @@ int netdev_get_etheraddr(const struct netdev *, uint8_t mac[6]);
 
 /* PHY interface. */
 bool netdev_get_carrier(const struct netdev *);
-bool netdev_get_miimon(const struct netdev *);
+int netdev_set_miimon_interval(struct netdev *, long long int interval);
 int netdev_get_features(const struct netdev *,
                         uint32_t *current, uint32_t *advertised,
                         uint32_t *supported, uint32_t *peer);
diff --git a/vswitchd/bridge.c b/vswitchd/bridge.c
index 3faeee1..c3fb919 100644
--- a/vswitchd/bridge.c
+++ b/vswitchd/bridge.c
@@ -2226,6 +2226,7 @@ port_configure_bond(struct port *port, struct bond_settings *s,
 {
     const char *detect_s;
     struct iface *iface;
+    int miimon_interval;
     size_t i;
 
     s->name = port->name;
@@ -2237,18 +2238,19 @@ port_configure_bond(struct port *port, struct bond_settings *s,
                   bond_mode_to_string(s->balance));
     }
 
-    s->detect = BLSM_CARRIER;
-    detect_s = get_port_other_config(port->cfg, "bond-detect-mode", NULL);
-    if (detect_s && !bond_detect_mode_from_string(&s->detect, detect_s)) {
-        VLOG_WARN("port %s: unsupported bond-detect-mode %s, "
-                  "defaulting to %s",
-                  port->name, detect_s, bond_detect_mode_to_string(s->detect));
+    miimon_interval = atoi(get_port_other_config(port->cfg,
+                                                 "bond-miimon-interval", "0"));
+    if (miimon_interval <= 0) {
+        miimon_interval = 200;
     }
 
-    s->miimon_interval = atoi(
-        get_port_other_config(port->cfg, "bond-miimon-interval", "200"));
-    if (s->miimon_interval < 100) {
-        s->miimon_interval = 100;
+    detect_s = get_port_other_config(port->cfg, "bond-detect-mode", "carrier");
+    if (!strcmp(detect_s, "carrier")) {
+        miimon_interval = 0;
+    } else if (strcmp(detect_s, "miimon")) {
+        VLOG_WARN("port %s: unsupported bond-detect-mode %s, "
+                  "defaulting to carrier", port->name, detect_s);
+        miimon_interval = 0;
     }
 
     s->up_delay = MAX(0, port->cfg->bond_updelay);
@@ -2272,6 +2274,8 @@ port_configure_bond(struct port *port, struct bond_settings *s,
             stable_id = iface->ofp_port;
         }
         bond_stable_ids[i++] = stable_id;
+
+        netdev_set_miimon_interval(iface->netdev, miimon_interval);
     }
 }
 
-- 
1.7.4.4




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