af_packet: eliminate pgv_to_page on some arches

Some arches don't need flush_dcache_page(), and don't implement it, so
we can eliminate pgv_to_page() calls on those arches.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 17eafe5b48c6e9ea446a4fc8bb2ca2fa2bd13fa5..9292ec93eb52048e92ec0fd68568b5594130c804 100644 (file)
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -223,7 +223,7 @@ struct packet_skb_cb {
 
 #define PACKET_SKB_CB(__skb)   ((struct packet_skb_cb *)((__skb)->cb))
 
-static inline struct page *pgv_to_page(void *addr)
+static inline __pure struct page *pgv_to_page(void *addr)
 {
        if (is_vmalloc_addr(addr))
                return vmalloc_to_page(addr);
@@ -806,6 +806,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
 
        __packet_set_status(po, h.raw, status);
        smp_mb();
+#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
        {
                u8 *start, *end;
 
@@ -813,6 +814,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
                for (start = h.raw; start < end; start += PAGE_SIZE)
                        flush_dcache_page(pgv_to_page(start));
        }
+#endif
 
        sk->sk_data_ready(sk, 0);