[PATCH 05/10] net: Add skb_free_frag to replace use of put_page in freeing skb->head

Alexander Duyck
2015-05-07T04:12:03Z

This change adds a function called skb_free_frag which is meant to
compliment the function netdev_alloc_frag. The general idea is to enable a
more lightweight version of page freeing since we don't actually need all
the overhead of a put_page, and we don't quite fit the model of __free_pages.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
---
include/linux/skbuff.h | 5 +++++
net/core/skbuff.c | 10 ++++++----
2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 0039fcc45b3b..c0b574a414e7 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2182,6 +2182,11 @@ static inline struct sk_buff *netdev_alloc_skb_ip_align(struct net_device *dev,
return __netdev_alloc_skb_ip_align(dev, length, GFP_ATOMIC);
}

+static inline void skb_free_frag(void *addr)
+{
+ __free_page_frag(addr);
+}
+
void *napi_alloc_frag(unsigned int fragsz);
struct sk_buff *__napi_alloc_skb(struct napi_struct *napi,
unsigned int length, gfp_t gfp_mask);
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index dcc0e07abf47..d67e612bf0ef 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -436,7 +436,7 @@ struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int len,

skb = __build_skb(data, len);
if (unlikely(!skb)) {
- put_page(virt_to_head_page(data));
+ skb_free_frag(data);
return NULL;
}

@@ -490,7 +490,7 @@ struct sk_buff *__napi_alloc_skb(struct napi_struct *napi, unsigned int len,

skb = __build_skb(data, len);
if (unlikely(!skb)) {
- put_page(virt_to_head_page(data));
+ skb_free_frag(data);
return NULL;
}

@@ -549,10 +549,12 @@ static void skb_clone_fraglist(struct sk_buff *skb)

static void skb_free_head(struct sk_buff *skb)
{
+ unsigned char *head = skb->head;
+
if (skb->head_frag)
- put_page(virt_to_head_page(skb->head));
+ skb_free_frag(head);
else
- kfree(skb->head);
+ kfree(head);
}

static void skb_release_data(struct sk_buff *skb)

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