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-rw-r--r--net/core/skbuff.c22
1 files changed, 17 insertions, 5 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 27002df..387703f 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -611,8 +611,21 @@ struct sk_buff *skb_morph(struct sk_buff *dst, struct sk_buff *src)
}
EXPORT_SYMBOL_GPL(skb_morph);
-/* skb frags copy userspace buffers to kernel */
-static int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
+/* skb_copy_ubufs - copy userspace skb frags buffers to kernel
+ * @skb: the skb to modify
+ * @gfp_mask: allocation priority
+ *
+ * This must be called on SKBTX_DEV_ZEROCOPY skb.
+ * It will copy all frags into kernel and drop the reference
+ * to userspace pages.
+ *
+ * If this function is called from an interrupt gfp_mask() must be
+ * %GFP_ATOMIC.
+ *
+ * Returns 0 on success or a negative error code on failure
+ * to allocate kernel memory to copy to.
+ */
+int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
{
int i;
int num_frags = skb_shinfo(skb)->nr_frags;
@@ -652,6 +665,8 @@ static int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask)
skb_shinfo(skb)->frags[i - 1].page = head;
head = (struct page *)head->private;
}
+
+ skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY;
return 0;
}
@@ -677,7 +692,6 @@ struct sk_buff *skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
if (skb_copy_ubufs(skb, gfp_mask))
return NULL;
- skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY;
}
n = skb + 1;
@@ -803,7 +817,6 @@ struct sk_buff *pskb_copy(struct sk_buff *skb, gfp_t gfp_mask)
n = NULL;
goto out;
}
- skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY;
}
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
skb_shinfo(n)->frags[i] = skb_shinfo(skb)->frags[i];
@@ -896,7 +909,6 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
if (skb_shinfo(skb)->tx_flags & SKBTX_DEV_ZEROCOPY) {
if (skb_copy_ubufs(skb, gfp_mask))
goto nofrags;
- skb_shinfo(skb)->tx_flags &= ~SKBTX_DEV_ZEROCOPY;
}
for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
get_page(skb_shinfo(skb)->frags[i].page);

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