1 files changed, 41 insertions, 4 deletions

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 44ac121cfccb..c02f0a507ba8 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2787,6 +2787,8 @@ done:
 		skb->data_len  = 0;
 		skb_set_tail_pointer(skb, len);
 	}
+	if (!skb_shinfo(skb)->nr_frags && !skb_has_frag_list(skb))
+		skb->unreadable = 0;
 
 	if (!skb->sk || skb->destructor == sock_edemux)
 		skb_condense(skb);
@@ -2794,16 +2796,37 @@ done:
 }
 EXPORT_SYMBOL(___pskb_trim);
 
+static int pskb_trim_rcsum_complete(struct sk_buff *skb, unsigned int len)
+{
+	int delta = skb->len - len;
+
+	if (skb_frags_readable(skb)) {
+		skb->csum = csum_block_sub(skb->csum,
+					   skb_checksum(skb, len, delta, 0),
+					   len);
+		return 0;
+	}
+
+	if (len > skb_headlen(skb))
+		return -EFAULT;
+
+	/* The trimmed bytes are unreadable, but the remaining packet can be
+	 * checksummed by software after trimming.
+	 */
+	skb->ip_summed = CHECKSUM_NONE;
+	return 0;
+}
+
 /* Note : use pskb_trim_rcsum() instead of calling this directly
  */
 int pskb_trim_rcsum_slow(struct sk_buff *skb, unsigned int len)
 {
 	if (skb->ip_summed == CHECKSUM_COMPLETE) {
-		int delta = skb->len - len;
+		int err;
 
-		skb->csum = csum_block_sub(skb->csum,
-					   skb_checksum(skb, len, delta, 0),
-					   len);
+		err = pskb_trim_rcsum_complete(skb, len);
+		if (err)
+			return err;
 	} else if (skb->ip_summed == CHECKSUM_PARTIAL) {
 		int hdlen = (len > skb_headlen(skb)) ? skb_headlen(skb) : len;
 		int offset = skb_checksum_start_offset(skb) + skb->csum_offset;
@@ -6800,6 +6823,11 @@ static int pskb_carve_inside_header(struct sk_buff *skb, const u32 off,
 	skb_copy_from_linear_data_offset(skb, off, data, new_hlen);
 	skb->len -= off;
 
+	/* Remove SKBFL_MANAGED_FRAG_REFS instead of trying to honour it
+	 * while refcounting frags below.
+	 */
+	skb_zcopy_downgrade_managed(skb);
+
 	memcpy((struct skb_shared_info *)(data + size),
 	       skb_shinfo(skb),
 	       offsetof(struct skb_shared_info,
@@ -6810,6 +6838,8 @@ static int pskb_carve_inside_header(struct sk_buff *skb, const u32 off,
 			skb_kfree_head(data);
 			return -ENOMEM;
 		}
+		if (skb_zcopy(skb))
+			net_zcopy_get(skb_zcopy(skb));
 		for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
 			skb_frag_ref(skb, i);
 		if (skb_has_frag_list(skb))
@@ -6911,6 +6941,11 @@ static int pskb_carve_inside_nonlinear(struct sk_buff *skb, const u32 off,
 		return -ENOMEM;
 	size = SKB_WITH_OVERHEAD(size);
 
+	/* Remove SKBFL_MANAGED_FRAG_REFS instead of trying to honour it
+	 * while refcounting frags below.
+	 */
+	skb_zcopy_downgrade_managed(skb);
+
 	memcpy((struct skb_shared_info *)(data + size),
 	       skb_shinfo(skb), offsetof(struct skb_shared_info, frags[0]));
 	if (skb_orphan_frags(skb, gfp_mask)) {
@@ -6953,6 +6988,8 @@ static int pskb_carve_inside_nonlinear(struct sk_buff *skb, const u32 off,
 		skb_kfree_head(data);
 		return -ENOMEM;
 	}
+	if (skb_zcopy(skb))
+		net_zcopy_get(skb_zcopy(skb));
 	skb_release_data(skb, SKB_CONSUMED);
 
 	skb->head = data;