293 lines
7.2 KiB
C
293 lines
7.2 KiB
C
/*
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* SUCS NET3:
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*
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* Generic stream handling routines. These are generic for most
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* protocols. Even IP. Tonight 8-).
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* This is used because TCP, LLC (others too) layer all have mostly
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* identical sendmsg() and recvmsg() code.
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* So we (will) share it here.
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*
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* Authors: Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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* (from old tcp.c code)
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* Alan Cox <alan@redhat.com> (Borrowed comments 8-))
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*/
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#include <linux/module.h>
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#include <linux/net.h>
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#include <linux/signal.h>
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#include <linux/tcp.h>
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#include <linux/wait.h>
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#include <net/sock.h>
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/**
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* sk_stream_write_space - stream socket write_space callback.
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* @sk: socket
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*
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* FIXME: write proper description
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*/
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void sk_stream_write_space(struct sock *sk)
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{
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struct socket *sock = sk->sk_socket;
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if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk) && sock) {
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clear_bit(SOCK_NOSPACE, &sock->flags);
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if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
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wake_up_interruptible(sk->sk_sleep);
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if (sock->fasync_list && !(sk->sk_shutdown & SEND_SHUTDOWN))
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sock_wake_async(sock, 2, POLL_OUT);
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}
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}
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EXPORT_SYMBOL(sk_stream_write_space);
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/**
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* sk_stream_wait_connect - Wait for a socket to get into the connected state
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* @sk: sock to wait on
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* @timeo_p: for how long to wait
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*
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* Must be called with the socket locked.
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*/
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int sk_stream_wait_connect(struct sock *sk, long *timeo_p)
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{
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struct task_struct *tsk = current;
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DEFINE_WAIT(wait);
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int done;
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do {
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int err = sock_error(sk);
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if (err)
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return err;
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if ((1 << sk->sk_state) & ~(TCPF_SYN_SENT | TCPF_SYN_RECV))
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return -EPIPE;
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if (!*timeo_p)
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return -EAGAIN;
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if (signal_pending(tsk))
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return sock_intr_errno(*timeo_p);
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prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
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sk->sk_write_pending++;
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done = sk_wait_event(sk, timeo_p,
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!sk->sk_err &&
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!((1 << sk->sk_state) &
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~(TCPF_ESTABLISHED | TCPF_CLOSE_WAIT)));
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finish_wait(sk->sk_sleep, &wait);
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sk->sk_write_pending--;
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} while (!done);
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return 0;
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}
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EXPORT_SYMBOL(sk_stream_wait_connect);
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/**
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* sk_stream_closing - Return 1 if we still have things to send in our buffers.
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* @sk: socket to verify
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*/
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static inline int sk_stream_closing(struct sock *sk)
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{
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return (1 << sk->sk_state) &
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(TCPF_FIN_WAIT1 | TCPF_CLOSING | TCPF_LAST_ACK);
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}
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void sk_stream_wait_close(struct sock *sk, long timeout)
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{
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if (timeout) {
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DEFINE_WAIT(wait);
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do {
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prepare_to_wait(sk->sk_sleep, &wait,
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TASK_INTERRUPTIBLE);
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if (sk_wait_event(sk, &timeout, !sk_stream_closing(sk)))
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break;
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} while (!signal_pending(current) && timeout);
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finish_wait(sk->sk_sleep, &wait);
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}
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}
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EXPORT_SYMBOL(sk_stream_wait_close);
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/**
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* sk_stream_wait_memory - Wait for more memory for a socket
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* @sk: socket to wait for memory
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* @timeo_p: for how long
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*/
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int sk_stream_wait_memory(struct sock *sk, long *timeo_p)
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{
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int err = 0;
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long vm_wait = 0;
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long current_timeo = *timeo_p;
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DEFINE_WAIT(wait);
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if (sk_stream_memory_free(sk))
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current_timeo = vm_wait = (net_random() % (HZ / 5)) + 2;
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while (1) {
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set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
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prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
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if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
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goto do_error;
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if (!*timeo_p)
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goto do_nonblock;
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if (signal_pending(current))
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goto do_interrupted;
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clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
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if (sk_stream_memory_free(sk) && !vm_wait)
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break;
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set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
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sk->sk_write_pending++;
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sk_wait_event(sk, ¤t_timeo, !sk->sk_err &&
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!(sk->sk_shutdown & SEND_SHUTDOWN) &&
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sk_stream_memory_free(sk) &&
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vm_wait);
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sk->sk_write_pending--;
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if (vm_wait) {
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vm_wait -= current_timeo;
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current_timeo = *timeo_p;
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if (current_timeo != MAX_SCHEDULE_TIMEOUT &&
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(current_timeo -= vm_wait) < 0)
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current_timeo = 0;
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vm_wait = 0;
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}
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*timeo_p = current_timeo;
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}
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out:
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finish_wait(sk->sk_sleep, &wait);
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return err;
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do_error:
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err = -EPIPE;
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goto out;
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do_nonblock:
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err = -EAGAIN;
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goto out;
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do_interrupted:
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err = sock_intr_errno(*timeo_p);
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goto out;
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}
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EXPORT_SYMBOL(sk_stream_wait_memory);
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void sk_stream_rfree(struct sk_buff *skb)
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{
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struct sock *sk = skb->sk;
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skb_truesize_check(skb);
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atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
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sk->sk_forward_alloc += skb->truesize;
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}
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EXPORT_SYMBOL(sk_stream_rfree);
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int sk_stream_error(struct sock *sk, int flags, int err)
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{
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if (err == -EPIPE)
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err = sock_error(sk) ? : -EPIPE;
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if (err == -EPIPE && !(flags & MSG_NOSIGNAL))
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send_sig(SIGPIPE, current, 0);
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return err;
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}
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EXPORT_SYMBOL(sk_stream_error);
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void __sk_stream_mem_reclaim(struct sock *sk)
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{
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if (sk->sk_forward_alloc >= SK_STREAM_MEM_QUANTUM) {
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atomic_sub(sk->sk_forward_alloc / SK_STREAM_MEM_QUANTUM,
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sk->sk_prot->memory_allocated);
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sk->sk_forward_alloc &= SK_STREAM_MEM_QUANTUM - 1;
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if (*sk->sk_prot->memory_pressure &&
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(atomic_read(sk->sk_prot->memory_allocated) <
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sk->sk_prot->sysctl_mem[0]))
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*sk->sk_prot->memory_pressure = 0;
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}
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}
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EXPORT_SYMBOL(__sk_stream_mem_reclaim);
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int sk_stream_mem_schedule(struct sock *sk, int size, int kind)
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{
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int amt = sk_stream_pages(size);
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sk->sk_forward_alloc += amt * SK_STREAM_MEM_QUANTUM;
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atomic_add(amt, sk->sk_prot->memory_allocated);
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/* Under limit. */
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if (atomic_read(sk->sk_prot->memory_allocated) < sk->sk_prot->sysctl_mem[0]) {
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if (*sk->sk_prot->memory_pressure)
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*sk->sk_prot->memory_pressure = 0;
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return 1;
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}
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/* Over hard limit. */
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if (atomic_read(sk->sk_prot->memory_allocated) > sk->sk_prot->sysctl_mem[2]) {
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sk->sk_prot->enter_memory_pressure();
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goto suppress_allocation;
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}
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/* Under pressure. */
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if (atomic_read(sk->sk_prot->memory_allocated) > sk->sk_prot->sysctl_mem[1])
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sk->sk_prot->enter_memory_pressure();
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if (kind) {
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if (atomic_read(&sk->sk_rmem_alloc) < sk->sk_prot->sysctl_rmem[0])
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return 1;
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} else if (sk->sk_wmem_queued < sk->sk_prot->sysctl_wmem[0])
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return 1;
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if (!*sk->sk_prot->memory_pressure ||
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sk->sk_prot->sysctl_mem[2] > atomic_read(sk->sk_prot->sockets_allocated) *
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sk_stream_pages(sk->sk_wmem_queued +
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atomic_read(&sk->sk_rmem_alloc) +
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sk->sk_forward_alloc))
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return 1;
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suppress_allocation:
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if (!kind) {
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sk_stream_moderate_sndbuf(sk);
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/* Fail only if socket is _under_ its sndbuf.
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* In this case we cannot block, so that we have to fail.
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*/
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if (sk->sk_wmem_queued + size >= sk->sk_sndbuf)
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return 1;
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}
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/* Alas. Undo changes. */
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sk->sk_forward_alloc -= amt * SK_STREAM_MEM_QUANTUM;
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atomic_sub(amt, sk->sk_prot->memory_allocated);
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return 0;
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}
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EXPORT_SYMBOL(sk_stream_mem_schedule);
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void sk_stream_kill_queues(struct sock *sk)
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{
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/* First the read buffer. */
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__skb_queue_purge(&sk->sk_receive_queue);
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/* Next, the error queue. */
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__skb_queue_purge(&sk->sk_error_queue);
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/* Next, the write queue. */
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BUG_TRAP(skb_queue_empty(&sk->sk_write_queue));
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/* Account for returned memory. */
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sk_stream_mem_reclaim(sk);
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BUG_TRAP(!sk->sk_wmem_queued);
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BUG_TRAP(!sk->sk_forward_alloc);
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/* It is _impossible_ for the backlog to contain anything
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* when we get here. All user references to this socket
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* have gone away, only the net layer knows can touch it.
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*/
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}
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EXPORT_SYMBOL(sk_stream_kill_queues);
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