[CORE] Stack changes to add multiqueue hardware support API

Add the multiqueue hardware device support API to the core network
stack.  Allow drivers to allocate multiple queues and manage them at
the netdev level if they choose to do so.

Added a new field to sk_buff, namely queue_mapping, for drivers to
know which tx_ring to select based on OS classification of the flow.

Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 99 insertions, 9 deletions

diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
index f48eb89efd0f..6cdb97365e47 100644
--- a/include/linux/etherdevice.h
+++ b/include/linux/etherdevice.h
@@ -39,7 +39,8 @@ extern void		eth_header_cache_update(struct hh_cache *hh, struct net_device *dev
 extern int              eth_header_cache(struct neighbour *neigh,
                                          struct hh_cache *hh);
 
-extern struct net_device *alloc_etherdev(int sizeof_priv);
+extern struct net_device *alloc_etherdev_mq(int sizeof_priv, unsigned int queue_count);
+#define alloc_etherdev(sizeof_priv) alloc_etherdev_mq(sizeof_priv, 1)
 
 /**
  * is_zero_ether_addr - Determine if give Ethernet address is all zeros.
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 2c0cc19edfb2..9817821729c4 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -108,6 +108,14 @@ struct wireless_dev;
 #define MAX_HEADER (LL_MAX_HEADER + 48)
 #endif
 
+struct net_device_subqueue
+{
+        /* Give a control state for each queue.  This struct may contain
+         * per-queue locks in the future.
+         */
+        unsigned long   state;
+};
+
 /*
  *      Network device statistics. Akin to the 2.0 ether stats but
  *      with byte counters.
@@ -331,6 +339,7 @@ struct net_device
 #define NETIF_F_VLAN_CHALLENGED 1024    /* Device cannot handle VLAN packets */
 #define NETIF_F_GSO             2048    /* Enable software GSO. */
 #define NETIF_F_LLTX            4096    /* LockLess TX */
+#define NETIF_F_MULTI_QUEUE     16384   /* Has multiple TX/RX queues */
 
         /* Segmentation offload features */
 #define NETIF_F_GSO_SHIFT       16
@@ -557,6 +566,10 @@ struct net_device
 
         /* rtnetlink link ops */
         const struct rtnl_link_ops *rtnl_link_ops;
+
+        /* The TX queue control structures */
+        unsigned int                    egress_subqueue_count;
+        struct net_device_subqueue      egress_subqueue[0];
 };
 #define to_net_dev(d) container_of(d, struct net_device, dev)
 
@@ -565,9 +578,7 @@ struct net_device
 
 static inline void *netdev_priv(const struct net_device *dev)
 {
-        return (char *)dev + ((sizeof(struct net_device)
-                                        + NETDEV_ALIGN_CONST)
-                                & ~NETDEV_ALIGN_CONST);
+        return dev->priv;
 }
 
 #define SET_MODULE_OWNER(dev) do { } while (0)
@@ -719,6 +730,62 @@ static inline int netif_running(const struct net_device *dev)
         return test_bit(__LINK_STATE_START, &dev->state);
 }
 
+/*
+ * Routines to manage the subqueues on a device.  We only need start
+ * stop, and a check if it's stopped.  All other device management is
+ * done at the overall netdevice level.
+ * Also test the device if we're multiqueue.
+ */
+static inline void netif_start_subqueue(struct net_device *dev, u16 queue_index)
+{
+#ifdef CONFIG_NETDEVICES_MULTIQUEUE
+        clear_bit(__LINK_STATE_XOFF, &dev->egress_subqueue[queue_index].state);
+#endif
+}
+
+static inline void netif_stop_subqueue(struct net_device *dev, u16 queue_index)
+{
+#ifdef CONFIG_NETDEVICES_MULTIQUEUE
+#ifdef CONFIG_NETPOLL_TRAP
+        if (netpoll_trap())
+                return;
+#endif
+        set_bit(__LINK_STATE_XOFF, &dev->egress_subqueue[queue_index].state);
+#endif
+}
+
+static inline int netif_subqueue_stopped(const struct net_device *dev,
+                                         u16 queue_index)
+{
+#ifdef CONFIG_NETDEVICES_MULTIQUEUE
+        return test_bit(__LINK_STATE_XOFF,
+                        &dev->egress_subqueue[queue_index].state);
+#else
+        return 0;
+#endif
+}
+
+static inline void netif_wake_subqueue(struct net_device *dev, u16 queue_index)
+{
+#ifdef CONFIG_NETDEVICES_MULTIQUEUE
+#ifdef CONFIG_NETPOLL_TRAP
+        if (netpoll_trap())
+                return;
+#endif
+        if (test_and_clear_bit(__LINK_STATE_XOFF,
+                               &dev->egress_subqueue[queue_index].state))
+                __netif_schedule(dev);
+#endif
+}
+
+static inline int netif_is_multiqueue(const struct net_device *dev)
+{
+#ifdef CONFIG_NETDEVICES_MULTIQUEUE
+        return (!!(NETIF_F_MULTI_QUEUE & dev->features));
+#else
+        return 0;
+#endif
+}
 
 /* Use this variant when it is known for sure that it
  * is executing from interrupt context.
@@ -1009,8 +1076,11 @@ static inline void netif_tx_disable(struct net_device *dev)
 extern void             ether_setup(struct net_device *dev);
 
 /* Support for loadable net-drivers */
-extern struct net_device *alloc_netdev(int sizeof_priv, const char *name,
-                                       void (*setup)(struct net_device *));
+extern struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,
+                                       void (*setup)(struct net_device *),
+                                       unsigned int queue_count);
+#define alloc_netdev(sizeof_priv, name, setup) \
+        alloc_netdev_mq(sizeof_priv, name, setup, 1)
 extern int              register_netdev(struct net_device *dev);
 extern void             unregister_netdev(struct net_device *dev);
 /* Functions used for secondary unicast and multicast support */
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 881fe80f01d0..2d6a14f5f2f1 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -196,7 +196,6 @@ typedef unsigned char *sk_buff_data_t;
  *      @sk: Socket we are owned by
  *      @tstamp: Time we arrived
  *      @dev: Device we arrived on/are leaving by
- *      @iif: ifindex of device we arrived on
  *      @transport_header: Transport layer header
  *      @network_header: Network layer header
  *      @mac_header: Link layer header
@@ -231,6 +230,8 @@ typedef unsigned char *sk_buff_data_t;
  *      @nfctinfo: Relationship of this skb to the connection
  *      @nfct_reasm: netfilter conntrack re-assembly pointer
  *      @nf_bridge: Saved data about a bridged frame - see br_netfilter.c
+ *      @iif: ifindex of device we arrived on
+ *      @queue_mapping: Queue mapping for multiqueue devices
  *      @tc_index: Traffic control index
  *      @tc_verd: traffic control verdict
  *      @dma_cookie: a cookie to one of several possible DMA operations
@@ -246,8 +247,6 @@ struct sk_buff {
         struct sock             *sk;
         ktime_t                 tstamp;
         struct net_device       *dev;
-        int                     iif;
-        /* 4 byte hole on 64 bit*/
 
         struct  dst_entry       *dst;
         struct  sec_path        *sp;
@@ -290,12 +289,18 @@ struct sk_buff {
 #ifdef CONFIG_BRIDGE_NETFILTER
         struct nf_bridge_info   *nf_bridge;
 #endif
+
+        int                     iif;
+        __u16                   queue_mapping;
+
 #ifdef CONFIG_NET_SCHED
         __u16                   tc_index;       /* traffic control index */
 #ifdef CONFIG_NET_CLS_ACT
         __u16                   tc_verd;        /* traffic control verdict */
 #endif
 #endif
+        /* 2 byte hole */
+
 #ifdef CONFIG_NET_DMA
         dma_cookie_t            dma_cookie;
 #endif
@@ -1725,6 +1730,20 @@ static inline void skb_init_secmark(struct sk_buff *skb)
 { }
 #endif
 
+static inline void skb_set_queue_mapping(struct sk_buff *skb, u16 queue_mapping)
+{
+#ifdef CONFIG_NETDEVICES_MULTIQUEUE
+        skb->queue_mapping = queue_mapping;
+#endif
+}
+
+static inline void skb_copy_queue_mapping(struct sk_buff *to, const struct sk_buff *from)
+{
+#ifdef CONFIG_NETDEVICES_MULTIQUEUE
+        to->queue_mapping = from->queue_mapping;
+#endif
+}
+
 static inline int skb_is_gso(const struct sk_buff *skb)
 {
         return skb_shinfo(skb)->gso_size;