Skip to contentSkip to conversation

bonding: create bond_first_slave_rcu()

PATCH Superseded Ding Tianhong 2 participants 3 messages Nov 11, 2013 – Nov 12, 2013

Subsystems (3)

v3 of 6 Superseded Latest is v6 →

lore
Share & tools
lore
#0 lore raw

PATCH v3 5/10 bonding: create bond_first_slave_rcu()

The bond_first_slave_rcu() will be used to instead of bond_first_slave() in rcu_read_lock().

So move the struct netdev_adjacent to the netdevice.h and make the bond_first_slave_rcu() could use the struct.

---
 drivers/net/bonding/bonding.h |  9 +++++++++
 include/linux/netdevice.h     | 16 ++++++++++++++++
 net/core/dev.c                | 16 ----------------
 3 files changed, 25 insertions(+), 16 deletions(-)
drivers/net/bonding/bonding.h +9 -0
index 77a07a1..5d37606 100644
@@ -91,6 +91,15 @@
 		netdev_adjacent_get_private(bond_slave_list(bond)->prev) : \
 		NULL)
 
+/* Caller must have rcu_read_lock */
+#define bond_first_slave_rcu(bond) \
+	({struct list_head *__ptr = (bond_slave_list(bond)); \
+	 struct list_head *__next = ACCESS_ONCE(__ptr->next); \
+	 likely(__ptr != __next) ? \
+	 list_entry_rcu(__next, struct netdev_adjacent, list)->private : \
+		NULL; \
+	 })
+
 #define bond_is_first_slave(bond, pos) (pos == bond_first_slave(bond))
 #define bond_is_last_slave(bond, pos) (pos == bond_last_slave(bond))
 
include/linux/netdevice.h +16 -0
index 15fa01c..7ca0fc8 100644
@@ -2839,6 +2839,22 @@ extern int		netdev_tstamp_prequeue;
 extern int		weight_p;
 extern int		bpf_jit_enable;
 
+struct netdev_adjacent {
+	struct net_device *dev;
+
+	/* upper master flag, there can only be one master device per list */
+	bool master;
+
+	/* counter for the number of times this device was added to us */
+	u16 ref_nr;
+
+	/* private field for the users */
+	void *private;
+
+	struct list_head list;
+	struct rcu_head rcu;
+};
+
 bool netdev_has_upper_dev(struct net_device *dev, struct net_device *upper_dev);
 bool netdev_has_any_upper_dev(struct net_device *dev);
 struct net_device *netdev_all_upper_get_next_dev_rcu(struct net_device *dev,
net/core/dev.c +0 -16
index 8ffc52e..bcc5001 100644
@@ -4377,22 +4377,6 @@ softnet_break:
 	goto out;
 }
 
-struct netdev_adjacent {
-	struct net_device *dev;
-
-	/* upper master flag, there can only be one master device per list */
-	bool master;
-
-	/* counter for the number of times this device was added to us */
-	u16 ref_nr;
-
-	/* private field for the users */
-	void *private;
-
-	struct list_head list;
-	struct rcu_head rcu;
-};
-
 static struct netdev_adjacent *__netdev_find_adj_rcu(struct net_device *dev,
 						     struct net_device *adj_dev,
 						     struct list_head *adj_list)
Signature · 1 line
1.8.2.1
#1 lore raw
Quoted 5 lines · Ding Tianhong

The bond_first_slave_rcu() will be used to instead of bond_first_slave() in rcu_read_lock().

So move the struct netdev_adjacent to the netdevice.h and make the bond_first_slave_rcu() could use the struct.

The whole point in netdev_adjacent functions was to hide it from the users who wanted to use it directly. See

http://www.spinics.net/lists/netdev/msg248026.html

for reference. Please try to avoid that.

Quoted 89 lines

---

drivers/net/bonding/bonding.h |  9 +++++++++
include/linux/netdevice.h     | 16 ++++++++++++++++
net/core/dev.c                | 16 ----------------
3 files changed, 25 insertions(+), 16 deletions(-)
drivers/net/bonding/bonding.h +9 -0
index 77a07a1..5d37606 100644
@@ -91,6 +91,15 @@
 		netdev_adjacent_get_private(bond_slave_list(bond)->prev) : \
 		NULL)
 
+/* Caller must have rcu_read_lock */
+#define bond_first_slave_rcu(bond) \
+	({struct list_head *__ptr = (bond_slave_list(bond)); \
+	 struct list_head *__next = ACCESS_ONCE(__ptr->next); \
+	 likely(__ptr != __next) ? \
+	 list_entry_rcu(__next, struct netdev_adjacent, list)->private : \
+		NULL; \
+	 })
+
 #define bond_is_first_slave(bond, pos) (pos == bond_first_slave(bond))
 #define bond_is_last_slave(bond, pos) (pos == bond_last_slave(bond))
 
include/linux/netdevice.h +16 -0
index 15fa01c..7ca0fc8 100644
@@ -2839,6 +2839,22 @@ extern int		netdev_tstamp_prequeue;
 extern int		weight_p;
 extern int		bpf_jit_enable;
 
+struct netdev_adjacent {
+	struct net_device *dev;
+
+	/* upper master flag, there can only be one master device per list */
+	bool master;
+
+	/* counter for the number of times this device was added to us */
+	u16 ref_nr;
+
+	/* private field for the users */
+	void *private;
+
+	struct list_head list;
+	struct rcu_head rcu;
+};
+
 bool netdev_has_upper_dev(struct net_device *dev, struct net_device *upper_dev);
 bool netdev_has_any_upper_dev(struct net_device *dev);
 struct net_device *netdev_all_upper_get_next_dev_rcu(struct net_device *dev,
net/core/dev.c +0 -16
index 8ffc52e..bcc5001 100644
@@ -4377,22 +4377,6 @@ softnet_break:
 	goto out;
 }
 
-struct netdev_adjacent {
-	struct net_device *dev;
-
-	/* upper master flag, there can only be one master device per list */
-	bool master;
-
-	/* counter for the number of times this device was added to us */
-	u16 ref_nr;
-
-	/* private field for the users */
-	void *private;
-
-	struct list_head list;
-	struct rcu_head rcu;
-};
-
 static struct netdev_adjacent *__netdev_find_adj_rcu(struct net_device *dev,
 						     struct net_device *adj_dev,
 						     struct list_head *adj_list)
Signature · 1 line
1.8.2.1
#2 lore raw
Quoted 7 lines · Veaceslav Falico
Quoted 5 lines · Ding Tianhong

The bond_first_slave_rcu() will be used to instead of bond_first_slave() in rcu_read_lock().

So move the struct netdev_adjacent to the netdevice.h and make the bond_first_slave_rcu() could use the struct.

Quoted 7 lines

The whole point in netdev_adjacent functions was to hide it from the users who wanted to use it directly. See

http://www.spinics.net/lists/netdev/msg248026.html

for reference. Please try to avoid that.

Hi, Veaceslav
following the point, I rebuild the bond_first_slave_rcu(), if you have no comments, I will move it in the patch set.

Regards
Ding

+/* Caller must have rcu_read_lock */
+#define bond_first_slave_rcu(bond) \
+ netdev_lower_get_first_private_rcu(bond->dev)
+
#define bond_is_first_slave(bond, pos) (pos == bond_first_slave(bond)) #define bond_is_last_slave(bond, pos) (pos == bond_last_slave(bond))

include/linux/netdevice.h +1 -0
index 15fa01c..abfcfad 100644
@@ -2869,6 +2869,7 @@ void *netdev_lower_get_next_private_rcu(struct net_device *dev,
             priv = netdev_lower_get_next_private_rcu(dev, &(iter)))
 
 void *netdev_adjacent_get_private(struct list_head *adj_list);
+void *netdev_lower_get_first_private_rcu(struct net_device *dev);
 struct net_device *netdev_master_upper_dev_get(struct net_device *dev);
 struct net_device *netdev_master_upper_dev_get_rcu(struct net_device *dev);
 int netdev_upper_dev_link(struct net_device *dev, struct net_device *upper_dev);
net/core/dev.c +19 -0
index 8ffc52e..39bc202 100644
@@ -4570,6 +4570,27 @@ void *netdev_lower_get_next_private_rcu(struct net_device *dev,
 EXPORT_SYMBOL(netdev_lower_get_next_private_rcu);
 
 /**
+ * netdev_lower_get_first_private_rcu - Get the first ->private from the
+ *                                    lower neighbour list, RCU
+ *                                    variant
+ * @dev: device
+ *
+ * Gets the first netdev_adjacent->private from the dev's lower neighbour
+ * list. The caller must hold RCU read lock.
+ */
+void *netdev_lower_get_first_private_rcu(struct net_device *dev)
+{
+       struct netdev_adjacent *lower;
+
+       lower = list_first_or_null_rcu(&dev->adj_list.lower,
+                       struct netdev_adjacent, list);
+       if (lower)
+               return lower->private;
+       return NULL;
+}
+EXPORT_SYMBOL(netdev_lower_get_first_private_rcu);