4 files changed, 164 insertions, 8 deletions

diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt
index d5181ce9ff62..61f516b135b4 100644
--- a/Documentation/networking/bonding.txt
+++ b/Documentation/networking/bonding.txt
@@ -1,7 +1,7 @@
 
                 Linux Ethernet Bonding Driver HOWTO
 
-                Latest update: 12 November 2007
+                Latest update: 23 September 2009
 
 Initial release : Thomas Davis <tadavis at lbl.gov>
 Corrections, HA extensions : 2000/10/03-15 :
@@ -614,6 +614,46 @@ primary
 
         The primary option is only valid for active-backup mode.
 
+primary_reselect
+
+        Specifies the reselection policy for the primary slave.  This
+        affects how the primary slave is chosen to become the active slave
+        when failure of the active slave or recovery of the primary slave
+        occurs.  This option is designed to prevent flip-flopping between
+        the primary slave and other slaves.  Possible values are:
+
+        always or 0 (default)
+
+                The primary slave becomes the active slave whenever it
+                comes back up.
+
+        better or 1
+
+                The primary slave becomes the active slave when it comes
+                back up, if the speed and duplex of the primary slave is
+                better than the speed and duplex of the current active
+                slave.
+
+        failure or 2
+
+                The primary slave becomes the active slave only if the
+                current active slave fails and the primary slave is up.
+
+        The primary_reselect setting is ignored in two cases:
+
+                If no slaves are active, the first slave to recover is
+                made the active slave.
+
+                When initially enslaved, the primary slave is always made
+                the active slave.
+
+        Changing the primary_reselect policy via sysfs will cause an
+        immediate selection of the best active slave according to the new
+        policy.  This may or may not result in a change of the active
+        slave, depending upon the circumstances.
+
+        This option was added for bonding version 3.6.0.
+
 updelay
 
         Specifies the time, in milliseconds, to wait before enabling a
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 69c5b15e22da..19d57d537ec1 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -94,6 +94,7 @@ static int downdelay;
 static int use_carrier  = 1;
 static char *mode;
 static char *primary;
+static char *primary_reselect;
 static char *lacp_rate;
 static char *ad_select;
 static char *xmit_hash_policy;
@@ -126,6 +127,14 @@ MODULE_PARM_DESC(mode, "Mode of operation : 0 for balance-rr, "
                        "6 for balance-alb");
 module_param(primary, charp, 0);
 MODULE_PARM_DESC(primary, "Primary network device to use");
+module_param(primary_reselect, charp, 0);
+MODULE_PARM_DESC(primary_reselect, "Reselect primary slave "
+                                   "once it comes up; "
+                                   "0 for always (default), "
+                                   "1 for only if speed of primary is "
+                                   "better, "
+                                   "2 for only on active slave "
+                                   "failure");
 module_param(lacp_rate, charp, 0);
 MODULE_PARM_DESC(lacp_rate, "LACPDU tx rate to request from 802.3ad partner "
                             "(slow/fast)");
@@ -200,6 +209,13 @@ const struct bond_parm_tbl fail_over_mac_tbl[] = {
 {       NULL,                   -1},
 };
 
+const struct bond_parm_tbl pri_reselect_tbl[] = {
+{       "always",               BOND_PRI_RESELECT_ALWAYS},
+{       "better",               BOND_PRI_RESELECT_BETTER},
+{       "failure",              BOND_PRI_RESELECT_FAILURE},
+{       NULL,                   -1},
+};
+
 struct bond_parm_tbl ad_select_tbl[] = {
 {       "stable",       BOND_AD_STABLE},
 {       "bandwidth",    BOND_AD_BANDWIDTH},
@@ -1070,6 +1086,25 @@ out:
 
 }
 
+static bool bond_should_change_active(struct bonding *bond)
+{
+        struct slave *prim = bond->primary_slave;
+        struct slave *curr = bond->curr_active_slave;
+
+        if (!prim || !curr || curr->link != BOND_LINK_UP)
+                return true;
+        if (bond->force_primary) {
+                bond->force_primary = false;
+                return true;
+        }
+        if (bond->params.primary_reselect == BOND_PRI_RESELECT_BETTER &&
+            (prim->speed < curr->speed ||
+             (prim->speed == curr->speed && prim->duplex <= curr->duplex)))
+                return false;
+        if (bond->params.primary_reselect == BOND_PRI_RESELECT_FAILURE)
+                return false;
+        return true;
+}
 
 /**
  * find_best_interface - select the best available slave to be the active one
@@ -1094,7 +1129,8 @@ static struct slave *bond_find_best_slave(struct bonding *bond)
         }
 
         if ((bond->primary_slave) &&
-            bond->primary_slave->link == BOND_LINK_UP) {
+            bond->primary_slave->link == BOND_LINK_UP &&
+            bond_should_change_active(bond)) {
                 new_active = bond->primary_slave;
         }
 
@@ -1678,8 +1714,10 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 
         if (USES_PRIMARY(bond->params.mode) && bond->params.primary[0]) {
                 /* if there is a primary slave, remember it */
-                if (strcmp(bond->params.primary, new_slave->dev->name) == 0)
+                if (strcmp(bond->params.primary, new_slave->dev->name) == 0) {
                         bond->primary_slave = new_slave;
+                        bond->force_primary = true;
+                }
         }
 
         write_lock_bh(&bond->curr_slave_lock);
@@ -3201,11 +3239,14 @@ static void bond_info_show_master(struct seq_file *seq)
         }
 
         if (USES_PRIMARY(bond->params.mode)) {
-                seq_printf(seq, "Primary Slave: %s\n",
+                seq_printf(seq, "Primary Slave: %s",
                            (bond->primary_slave) ?
                            bond->primary_slave->dev->name : "None");
+                if (bond->primary_slave)
+                        seq_printf(seq, " (primary_reselect %s)",
+                   pri_reselect_tbl[bond->params.primary_reselect].modename);
 
-                seq_printf(seq, "Currently Active Slave: %s\n",
+                seq_printf(seq, "\nCurrently Active Slave: %s\n",
                            (curr) ? curr->dev->name : "None");
         }
 
@@ -4646,7 +4687,7 @@ int bond_parse_parm(const char *buf, const struct bond_parm_tbl *tbl)
 
 static int bond_check_params(struct bond_params *params)
 {
-        int arp_validate_value, fail_over_mac_value;
+        int arp_validate_value, fail_over_mac_value, primary_reselect_value;
 
         /*
          * Convert string parameters.
@@ -4945,6 +4986,20 @@ static int bond_check_params(struct bond_params *params)
                 primary = NULL;
         }
 
+        if (primary && primary_reselect) {
+                primary_reselect_value = bond_parse_parm(primary_reselect,
+                                                         pri_reselect_tbl);
+                if (primary_reselect_value == -1) {
+                        pr_err(DRV_NAME
+                               ": Error: Invalid primary_reselect \"%s\"\n",
+                               primary_reselect ==
+                                        NULL ? "NULL" : primary_reselect);
+                        return -EINVAL;
+                }
+        } else {
+                primary_reselect_value = BOND_PRI_RESELECT_ALWAYS;
+        }
+
         if (fail_over_mac) {
                 fail_over_mac_value = bond_parse_parm(fail_over_mac,
                                                       fail_over_mac_tbl);
@@ -4976,6 +5031,7 @@ static int bond_check_params(struct bond_params *params)
         params->use_carrier = use_carrier;
         params->lacp_fast = lacp_fast;
         params->primary[0] = 0;
+        params->primary_reselect = primary_reselect_value;
         params->fail_over_mac = fail_over_mac_value;
 
         if (primary) {
diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index ff449de6f3c0..dca7d82f7b97 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -1213,6 +1213,58 @@ static DEVICE_ATTR(primary, S_IRUGO | S_IWUSR,
                    bonding_show_primary, bonding_store_primary);
 
 /*
+ * Show and set the primary_reselect flag.
+ */
+static ssize_t bonding_show_primary_reselect(struct device *d,
+                                             struct device_attribute *attr,
+                                             char *buf)
+{
+        struct bonding *bond = to_bond(d);
+
+        return sprintf(buf, "%s %d\n",
+                       pri_reselect_tbl[bond->params.primary_reselect].modename,
+                       bond->params.primary_reselect);
+}
+
+static ssize_t bonding_store_primary_reselect(struct device *d,
+                                              struct device_attribute *attr,
+                                              const char *buf, size_t count)
+{
+        int new_value, ret = count;
+        struct bonding *bond = to_bond(d);
+
+        if (!rtnl_trylock())
+                return restart_syscall();
+
+        new_value = bond_parse_parm(buf, pri_reselect_tbl);
+        if (new_value < 0)  {
+                pr_err(DRV_NAME
+                       ": %s: Ignoring invalid primary_reselect value %.*s.\n",
+                       bond->dev->name,
+                       (int) strlen(buf) - 1, buf);
+                ret = -EINVAL;
+                goto out;
+        }
+
+        bond->params.primary_reselect = new_value;
+        pr_info(DRV_NAME ": %s: setting primary_reselect to %s (%d).\n",
+                bond->dev->name, pri_reselect_tbl[new_value].modename,
+                new_value);
+
+        read_lock(&bond->lock);
+        write_lock_bh(&bond->curr_slave_lock);
+        bond_select_active_slave(bond);
+        write_unlock_bh(&bond->curr_slave_lock);
+        read_unlock(&bond->lock);
+out:
+        rtnl_unlock();
+        return ret;
+}
+static DEVICE_ATTR(primary_reselect, S_IRUGO | S_IWUSR,
+                   bonding_show_primary_reselect,
+                   bonding_store_primary_reselect);
+
+/*
  * Show and set the use_carrier flag.
  */
 static ssize_t bonding_show_carrier(struct device *d,
@@ -1501,6 +1553,7 @@ static struct attribute *per_bond_attrs[] = {
         &dev_attr_num_unsol_na.attr,
         &dev_attr_miimon.attr,
         &dev_attr_primary.attr,
+        &dev_attr_primary_reselect.attr,
         &dev_attr_use_carrier.attr,
         &dev_attr_active_slave.attr,
         &dev_attr_mii_status.attr,
diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index 68247714466f..9c03c2ee074d 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -23,8 +23,8 @@
 #include "bond_3ad.h"
 #include "bond_alb.h"
 
-#define DRV_VERSION     "3.5.0"
-#define DRV_RELDATE     "November 4, 2008"
+#define DRV_VERSION     "3.6.0"
+#define DRV_RELDATE     "September 26, 2009"
 #define DRV_NAME        "bonding"
 #define DRV_DESCRIPTION "Ethernet Channel Bonding Driver"
 
@@ -131,6 +131,7 @@ struct bond_params {
         int lacp_fast;
         int ad_select;
         char primary[IFNAMSIZ];
+        int primary_reselect;
         __be32 arp_targets[BOND_MAX_ARP_TARGETS];
 };
 
@@ -190,6 +191,7 @@ struct bonding {
         struct   slave *curr_active_slave;
         struct   slave *current_arp_slave;
         struct   slave *primary_slave;
+        bool     force_primary;
         s32      slave_cnt; /* never change this value outside the attach/detach wrappers */
         rwlock_t lock;
         rwlock_t curr_slave_lock;
@@ -258,6 +260,10 @@ static inline bool bond_is_lb(const struct bonding *bond)
                 || bond->params.mode == BOND_MODE_ALB;
 }
 
+#define BOND_PRI_RESELECT_ALWAYS        0
+#define BOND_PRI_RESELECT_BETTER        1
+#define BOND_PRI_RESELECT_FAILURE       2
+
 #define BOND_FOM_NONE                   0
 #define BOND_FOM_ACTIVE                 1
 #define BOND_FOM_FOLLOW                 2
@@ -348,6 +354,7 @@ extern const struct bond_parm_tbl bond_mode_tbl[];
 extern const struct bond_parm_tbl xmit_hashtype_tbl[];
 extern const struct bond_parm_tbl arp_validate_tbl[];
 extern const struct bond_parm_tbl fail_over_mac_tbl[];
+extern const struct bond_parm_tbl pri_reselect_tbl[];
 extern struct bond_parm_tbl ad_select_tbl[];
 
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)