static void trim_sg(struct sock *sk, struct scatterlist *sg,
int *sg_num_elem, unsigned int *sg_size, int target_size)
{
int i = *sg_num_elem - 1;
int trim = *sg_size - target_size;
if (trim <= 0) {
WARN_ON(trim < 0);
return;
}
*sg_size = target_size;
while (trim >= sg[i].length) {
trim -= sg[i].length;
sk_mem_uncharge(sk, sg[i].length);
put_page(sg_page(&sg[i]));
i--;
if (i < 0)
goto out;
}
sg[i].length -= trim;
sk_mem_uncharge(sk, trim);
out:
*sg_num_elem = i + 1;
}
static void free_sg(struct sock *sk, struct scatterlist *sg,
int *sg_num_elem, unsigned int *sg_size)
{
int i, n = *sg_num_elem;
for (i = 0; i < n; ++i) {
sk_mem_uncharge(sk, sg[i].length);
put_page(sg_page(&sg[i]));
}
*sg_num_elem = 0;
*sg_size = 0;
}
static void kcm_rfree(struct sk_buff *skb)
{
struct sock *sk = skb->sk;
struct kcm_sock *kcm = kcm_sk(sk);
struct kcm_mux *mux = kcm->mux;
unsigned int len = skb->truesize;
sk_mem_uncharge(sk, len);
atomic_sub(len, &sk->sk_rmem_alloc);
/* For reading rx_wait and rx_psock without holding lock */
smp_mb__after_atomic();
if (!kcm->rx_wait && !kcm->rx_psock &&
sk_rmem_alloc_get(sk) < sk->sk_rcvlowat) {
spin_lock_bh(&mux->rx_lock);
kcm_rcv_ready(kcm);
spin_unlock_bh(&mux->rx_lock);
}
}