rps: cleanups

struct softnet_data holds many queues, so consistent use "sd" name
instead of "queue" is better.

Adds a rps_ipi_queued() helper to cleanup enqueue_to_backlog()

Adds a _and_irq_disable suffix to net_rps_action() name, as David
suggested.

incr_input_queue_head() becomes input_queue_head_incr()

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 80 insertions, 69 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 05a2b294906b..7f5755b0a57c 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -208,17 +208,17 @@ static inline struct hlist_head *dev_index_hash(struct net *net, int ifindex)
         return &net->dev_index_head[ifindex & (NETDEV_HASHENTRIES - 1)];
 }
 
-static inline void rps_lock(struct softnet_data *queue)
+static inline void rps_lock(struct softnet_data *sd)
 {
 #ifdef CONFIG_RPS
-        spin_lock(&queue->input_pkt_queue.lock);
+        spin_lock(&sd->input_pkt_queue.lock);
 #endif
 }
 
-static inline void rps_unlock(struct softnet_data *queue)
+static inline void rps_unlock(struct softnet_data *sd)
 {
 #ifdef CONFIG_RPS
-        spin_unlock(&queue->input_pkt_queue.lock);
+        spin_unlock(&sd->input_pkt_queue.lock);
 #endif
 }
 
@@ -2346,63 +2346,74 @@ done:
 }
 
 /* Called from hardirq (IPI) context */
-static void trigger_softirq(void *data)
+static void rps_trigger_softirq(void *data)
 {
-        struct softnet_data *queue = data;
-        __napi_schedule(&queue->backlog);
+        struct softnet_data *sd = data;
+
+        __napi_schedule(&sd->backlog);
         __get_cpu_var(netdev_rx_stat).received_rps++;
 }
+
 #endif /* CONFIG_RPS */
 
 /*
+ * Check if this softnet_data structure is another cpu one
+ * If yes, queue it to our IPI list and return 1
+ * If no, return 0
+ */
+static int rps_ipi_queued(struct softnet_data *sd)
+{
+#ifdef CONFIG_RPS
+        struct softnet_data *mysd = &__get_cpu_var(softnet_data);
+
+        if (sd != mysd) {
+                sd->rps_ipi_next = mysd->rps_ipi_list;
+                mysd->rps_ipi_list = sd;
+
+                __raise_softirq_irqoff(NET_RX_SOFTIRQ);
+                return 1;
+        }
+#endif /* CONFIG_RPS */
+        return 0;
+}
+
+/*
  * enqueue_to_backlog is called to queue an skb to a per CPU backlog
  * queue (may be a remote CPU queue).
  */
 static int enqueue_to_backlog(struct sk_buff *skb, int cpu,
                               unsigned int *qtail)
 {
-        struct softnet_data *queue;
+        struct softnet_data *sd;
         unsigned long flags;
 
-        queue = &per_cpu(softnet_data, cpu);
+        sd = &per_cpu(softnet_data, cpu);
 
         local_irq_save(flags);
         __get_cpu_var(netdev_rx_stat).total++;
 
-        rps_lock(queue);
-        if (queue->input_pkt_queue.qlen <= netdev_max_backlog) {
-                if (queue->input_pkt_queue.qlen) {
+        rps_lock(sd);
+        if (sd->input_pkt_queue.qlen <= netdev_max_backlog) {
+                if (sd->input_pkt_queue.qlen) {
 enqueue:
-                        __skb_queue_tail(&queue->input_pkt_queue, skb);
+                        __skb_queue_tail(&sd->input_pkt_queue, skb);
 #ifdef CONFIG_RPS
-                        *qtail = queue->input_queue_head +
-                            queue->input_pkt_queue.qlen;
+                        *qtail = sd->input_queue_head + sd->input_pkt_queue.qlen;
 #endif
-                        rps_unlock(queue);
+                        rps_unlock(sd);
                         local_irq_restore(flags);
                         return NET_RX_SUCCESS;
                 }
 
                 /* Schedule NAPI for backlog device */
-                if (napi_schedule_prep(&queue->backlog)) {
-#ifdef CONFIG_RPS
-                        if (cpu != smp_processor_id()) {
-                                struct softnet_data *myqueue;
-
-                                myqueue = &__get_cpu_var(softnet_data);
-                                queue->rps_ipi_next = myqueue->rps_ipi_list;
-                                myqueue->rps_ipi_list = queue;
-
-                                __raise_softirq_irqoff(NET_RX_SOFTIRQ);
-                                goto enqueue;
-                        }
-#endif
-                        __napi_schedule(&queue->backlog);
+                if (napi_schedule_prep(&sd->backlog)) {
+                        if (!rps_ipi_queued(sd))
+                                __napi_schedule(&sd->backlog);
                 }
                 goto enqueue;
         }
 
-        rps_unlock(queue);
+        rps_unlock(sd);
 
         __get_cpu_var(netdev_rx_stat).dropped++;
         local_irq_restore(flags);
@@ -2903,17 +2914,17 @@ EXPORT_SYMBOL(netif_receive_skb);
 static void flush_backlog(void *arg)
 {
         struct net_device *dev = arg;
-        struct softnet_data *queue = &__get_cpu_var(softnet_data);
+        struct softnet_data *sd = &__get_cpu_var(softnet_data);
         struct sk_buff *skb, *tmp;
 
-        rps_lock(queue);
-        skb_queue_walk_safe(&queue->input_pkt_queue, skb, tmp)
+        rps_lock(sd);
+        skb_queue_walk_safe(&sd->input_pkt_queue, skb, tmp)
                 if (skb->dev == dev) {
-                        __skb_unlink(skb, &queue->input_pkt_queue);
+                        __skb_unlink(skb, &sd->input_pkt_queue);
                         kfree_skb(skb);
-                        incr_input_queue_head(queue);
+                        input_queue_head_incr(sd);
                 }
-        rps_unlock(queue);
+        rps_unlock(sd);
 }
 
 static int napi_gro_complete(struct sk_buff *skb)
@@ -3219,23 +3230,23 @@ EXPORT_SYMBOL(napi_gro_frags);
 static int process_backlog(struct napi_struct *napi, int quota)
 {
         int work = 0;
-        struct softnet_data *queue = &__get_cpu_var(softnet_data);
+        struct softnet_data *sd = &__get_cpu_var(softnet_data);
 
         napi->weight = weight_p;
         do {
                 struct sk_buff *skb;
 
                 local_irq_disable();
-                rps_lock(queue);
-                skb = __skb_dequeue(&queue->input_pkt_queue);
+                rps_lock(sd);
+                skb = __skb_dequeue(&sd->input_pkt_queue);
                 if (!skb) {
                         __napi_complete(napi);
-                        rps_unlock(queue);
+                        rps_unlock(sd);
                         local_irq_enable();
                         break;
                 }
-                incr_input_queue_head(queue);
-                rps_unlock(queue);
+                input_queue_head_incr(sd);
+                rps_unlock(sd);
                 local_irq_enable();
 
                 __netif_receive_skb(skb);
@@ -3331,24 +3342,25 @@ EXPORT_SYMBOL(netif_napi_del);
  * net_rps_action sends any pending IPI's for rps.
  * Note: called with local irq disabled, but exits with local irq enabled.
  */
-static void net_rps_action(void)
+static void net_rps_action_and_irq_disable(void)
 {
 #ifdef CONFIG_RPS
-        struct softnet_data *locqueue = &__get_cpu_var(softnet_data);
-        struct softnet_data *remqueue = locqueue->rps_ipi_list;
+        struct softnet_data *sd = &__get_cpu_var(softnet_data);
+        struct softnet_data *remsd = sd->rps_ipi_list;
 
-        if (remqueue) {
-                locqueue->rps_ipi_list = NULL;
+        if (remsd) {
+                sd->rps_ipi_list = NULL;
 
                 local_irq_enable();
 
                 /* Send pending IPI's to kick RPS processing on remote cpus. */
-                while (remqueue) {
-                        struct softnet_data *next = remqueue->rps_ipi_next;
-                        if (cpu_online(remqueue->cpu))
-                                __smp_call_function_single(remqueue->cpu,
-                                                           &remqueue->csd, 0);
-                        remqueue = next;
+                while (remsd) {
+                        struct softnet_data *next = remsd->rps_ipi_next;
+
+                        if (cpu_online(remsd->cpu))
+                                __smp_call_function_single(remsd->cpu,
+                                                           &remsd->csd, 0);
+                        remsd = next;
                 }
         } else
 #endif
@@ -3423,7 +3435,7 @@ static void net_rx_action(struct softirq_action *h)
                 netpoll_poll_unlock(have);
         }
 out:
-        net_rps_action();
+        net_rps_action_and_irq_disable();
 
 #ifdef CONFIG_NET_DMA
         /*
@@ -5595,7 +5607,7 @@ static int dev_cpu_callback(struct notifier_block *nfb,
         /* Process offline CPU's input_pkt_queue */
         while ((skb = __skb_dequeue(&oldsd->input_pkt_queue))) {
                 netif_rx(skb);
-                incr_input_queue_head(oldsd);
+                input_queue_head_incr(oldsd);
         }
 
         return NOTIFY_OK;
@@ -5812,24 +5824,23 @@ static int __init net_dev_init(void)
          */
 
         for_each_possible_cpu(i) {
-                struct softnet_data *queue;
+                struct softnet_data *sd = &per_cpu(softnet_data, i);
 
-                queue = &per_cpu(softnet_data, i);
-                skb_queue_head_init(&queue->input_pkt_queue);
-                queue->completion_queue = NULL;
-                INIT_LIST_HEAD(&queue->poll_list);
+                skb_queue_head_init(&sd->input_pkt_queue);
+                sd->completion_queue = NULL;
+                INIT_LIST_HEAD(&sd->poll_list);
 
 #ifdef CONFIG_RPS
-                queue->csd.func = trigger_softirq;
-                queue->csd.info = queue;
-                queue->csd.flags = 0;
-                queue->cpu = i;
+                sd->csd.func = rps_trigger_softirq;
+                sd->csd.info = sd;
+                sd->csd.flags = 0;
+                sd->cpu = i;
 #endif
 
-                queue->backlog.poll = process_backlog;
-                queue->backlog.weight = weight_p;
-                queue->backlog.gro_list = NULL;
-                queue->backlog.gro_count = 0;
+                sd->backlog.poll = process_backlog;
+                sd->backlog.weight = weight_p;
+                sd->backlog.gro_list = NULL;
+                sd->backlog.gro_count = 0;
         }
 
         dev_boot_phase = 0;