SKBFL_SHARED_FRAG
skb_shinfo(skb)->flags & SKBFL_SHARED_FRAG;
#define SKBFL_ZEROCOPY_FRAG (SKBFL_ZEROCOPY_ENABLE | SKBFL_SHARED_FRAG)
const int zc_flags = SKBFL_SHARED_FRAG | SKBFL_PURE_ZEROCOPY;
SKBFL_SHARED_FRAG;
skb_shinfo(skb)->flags |= SKBFL_SHARED_FRAG;
skb_shinfo(skb)->flags |= SKBFL_SHARED_FRAG;