ftgmac100: Disable HW checksum generation on AST2400, enable on others

[karo-tx-linux.git] / fs / eventpoll.c

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 341251421ced00ab1be854c4145cf408cfc93c2f..5420767c9b686a7a9db30bbf932e85071c83c9f6 100644 (file)
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -42,6 +42,7 @@
 #include <linux/seq_file.h>
 #include <linux/compat.h>
 #include <linux/rculist.h>
+#include <net/busy_poll.h>
 
 /*
  * LOCKING:
@@ -224,6 +225,11 @@ struct eventpoll {
        /* used to optimize loop detection check */
        int visited;
        struct list_head visited_list_link;
+
+#ifdef CONFIG_NET_RX_BUSY_POLL
+       /* used to track busy poll napi_id */
+       unsigned int napi_id;
+#endif
 };
 
 /* Wait structure used by the poll hooks */
@@ -384,6 +390,77 @@ static inline int ep_events_available(struct eventpoll *ep)
        return !list_empty(&ep->rdllist) || ep->ovflist != EP_UNACTIVE_PTR;
 }
 
+#ifdef CONFIG_NET_RX_BUSY_POLL
+static bool ep_busy_loop_end(void *p, unsigned long start_time)
+{
+       struct eventpoll *ep = p;
+
+       return ep_events_available(ep) || busy_loop_timeout(start_time);
+}
+#endif /* CONFIG_NET_RX_BUSY_POLL */
+
+/*
+ * Busy poll if globally on and supporting sockets found && no events,
+ * busy loop will return if need_resched or ep_events_available.
+ *
+ * we must do our busy polling with irqs enabled
+ */
+static void ep_busy_loop(struct eventpoll *ep, int nonblock)
+{
+#ifdef CONFIG_NET_RX_BUSY_POLL
+       unsigned int napi_id = READ_ONCE(ep->napi_id);
+
+       if ((napi_id >= MIN_NAPI_ID) && net_busy_loop_on())
+               napi_busy_loop(napi_id, nonblock ? NULL : ep_busy_loop_end, ep);
+#endif
+}
+
+static inline void ep_reset_busy_poll_napi_id(struct eventpoll *ep)
+{
+#ifdef CONFIG_NET_RX_BUSY_POLL
+       if (ep->napi_id)
+               ep->napi_id = 0;
+#endif
+}
+
+/*
+ * Set epoll busy poll NAPI ID from sk.
+ */
+static inline void ep_set_busy_poll_napi_id(struct epitem *epi)
+{
+#ifdef CONFIG_NET_RX_BUSY_POLL
+       struct eventpoll *ep;
+       unsigned int napi_id;
+       struct socket *sock;
+       struct sock *sk;
+       int err;
+
+       if (!net_busy_loop_on())
+               return;
+
+       sock = sock_from_file(epi->ffd.file, &err);
+       if (!sock)
+               return;
+
+       sk = sock->sk;
+       if (!sk)
+               return;
+
+       napi_id = READ_ONCE(sk->sk_napi_id);
+       ep = epi->ep;
+
+       /* Non-NAPI IDs can be rejected
+        *      or
+        * Nothing to do if we already have this ID
+        */
+       if (napi_id < MIN_NAPI_ID || napi_id == ep->napi_id)
+               return;
+
+       /* record NAPI ID for use in next busy poll */
+       ep->napi_id = napi_id;
+#endif
+}
+
 /**
  * ep_call_nested - Perform a bound (possibly) nested call, by checking
  *                  that the recursion limit is not exceeded, and that
@@ -1022,6 +1099,8 @@ static int ep_poll_callback(wait_queue_t *wait, unsigned mode, int sync, void *k
 
        spin_lock_irqsave(&ep->lock, flags);
 
+       ep_set_busy_poll_napi_id(epi);
+
        /*
         * If the event mask does not contain any poll(2) event, we consider the
         * descriptor to be disabled. This condition is likely the effect of the
@@ -1363,6 +1442,9 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event,
        /* We have to drop the new item inside our item list to keep track of it */
        spin_lock_irqsave(&ep->lock, flags);
 
+       /* record NAPI ID of new item if present */
+       ep_set_busy_poll_napi_id(epi);
+
        /* If the file is already "ready" we drop it inside the ready list */
        if ((revents & event->events) && !ep_is_linked(&epi->rdllink)) {
                list_add_tail(&epi->rdllink, &ep->rdllist);
@@ -1637,9 +1719,20 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
        }
 
 fetch_events:
+
+       if (!ep_events_available(ep))
+               ep_busy_loop(ep, timed_out);
+
        spin_lock_irqsave(&ep->lock, flags);
 
        if (!ep_events_available(ep)) {
+               /*
+                * Busy poll timed out.  Drop NAPI ID for now, we can add
+                * it back in when we have moved a socket with a valid NAPI
+                * ID onto the ready list.
+                */
+               ep_reset_busy_poll_napi_id(ep);
+
                /*
                 * We don't have any available event to return to the caller.
                 * We need to sleep here, and we will be wake up by