1 files changed, 28 insertions, 9 deletions

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 857e4e6f751a..1bca1e0fc8f7 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -77,8 +77,8 @@
 #include <linux/capability.h>
 #include <linux/user_namespace.h>
 
-struct kmem_cache *skbuff_head_cache __read_mostly;
-static struct kmem_cache *skbuff_fclone_cache __read_mostly;
+struct kmem_cache *skbuff_head_cache __ro_after_init;
+static struct kmem_cache *skbuff_fclone_cache __ro_after_init;
 int sysctl_max_skb_frags __read_mostly = MAX_SKB_FRAGS;
 EXPORT_SYMBOL(sysctl_max_skb_frags);
 
@@ -890,7 +890,7 @@ struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src)
 }
 EXPORT_SYMBOL_GPL(skb_morph);
 
-static int mm_account_pinned_pages(struct mmpin *mmp, size_t size)
+int mm_account_pinned_pages(struct mmpin *mmp, size_t size)
 {
 	unsigned long max_pg, num_pg, new_pg, old_pg;
 	struct user_struct *user;
@@ -919,14 +919,16 @@ static int mm_account_pinned_pages(struct mmpin *mmp, size_t size)
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(mm_account_pinned_pages);
 
-static void mm_unaccount_pinned_pages(struct mmpin *mmp)
+void mm_unaccount_pinned_pages(struct mmpin *mmp)
 {
 	if (mmp->user) {
 		atomic_long_sub(mmp->num_pg, &mmp->user->locked_vm);
 		free_uid(mmp->user);
 	}
 }
+EXPORT_SYMBOL_GPL(mm_unaccount_pinned_pages);
 
 struct ubuf_info *sock_zerocopy_alloc(struct sock *sk, size_t size)
 {
@@ -3458,6 +3460,19 @@ void *skb_pull_rcsum(struct sk_buff *skb, unsigned int len)
 }
 EXPORT_SYMBOL_GPL(skb_pull_rcsum);
 
+static inline skb_frag_t skb_head_frag_to_page_desc(struct sk_buff *frag_skb)
+{
+	skb_frag_t head_frag;
+	struct page *page;
+
+	page = virt_to_head_page(frag_skb->head);
+	head_frag.page.p = page;
+	head_frag.page_offset = frag_skb->data -
+		(unsigned char *)page_address(page);
+	head_frag.size = skb_headlen(frag_skb);
+	return head_frag;
+}
+
 /**
  *	skb_segment - Perform protocol segmentation on skb.
  *	@head_skb: buffer to segment
@@ -3662,15 +3677,19 @@ normal:
 
 		while (pos < offset + len) {
 			if (i >= nfrags) {
-				BUG_ON(skb_headlen(list_skb));
-
 				i = 0;
 				nfrags = skb_shinfo(list_skb)->nr_frags;
 				frag = skb_shinfo(list_skb)->frags;
 				frag_skb = list_skb;
+				if (!skb_headlen(list_skb)) {
+					BUG_ON(!nfrags);
+				} else {
+					BUG_ON(!list_skb->head_frag);
 
-				BUG_ON(!nfrags);
-
+					/* to make room for head_frag. */
+					i--;
+					frag--;
+				}
 				if (skb_orphan_frags(frag_skb, GFP_ATOMIC) ||
 				    skb_zerocopy_clone(nskb, frag_skb,
 						       GFP_ATOMIC))
@@ -3687,7 +3706,7 @@ normal:
 				goto err;
 			}
 
-			*nskb_frag = *frag;
+			*nskb_frag = (i < 0) ? skb_head_frag_to_page_desc(frag_skb) : *frag;
 			__skb_frag_ref(nskb_frag);
 			size = skb_frag_size(nskb_frag);