net: Don't write to current task flags on every packet received.
Even for non-pfmalloc SKBs, __netif_receive_skb() will do a tsk_restore_flags() on current unconditionally. Make __netif_receive_skb() a shim around the existing code, renamed to __netif_receive_skb_core(). Let __netif_receive_skb() wrap the __netif_receive_skb_core() call with the task flag modifications, if necessary. Signed-off-by: David S. Miller <firstname.lastname@example.org>