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net/socket: factor out helpers for memory and queue manipulation
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Basic sock operations that udp code can use with its own
memory accounting schema. No functional change is introduced
in the existing APIs.

v4 -> v5:
  - avoid whitespace changes

v2 -> v4:
  - avoid exporting __sock_enqueue_skb

v1 -> v2:
  - avoid export sock_rmem_free

Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Paolo Abeni authored and David S. Miller committed Oct 22, 2016
1 parent 8b1efc0 commit f8c3bf0
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Showing 3 changed files with 71 additions and 33 deletions.
4 changes: 4 additions & 0 deletions include/net/sock.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1274,7 +1274,9 @@ static inline struct inode *SOCK_INODE(struct socket *socket)
/*
* Functions for memory accounting
*/
int __sk_mem_raise_allocated(struct sock *sk, int size, int amt, int kind);
int __sk_mem_schedule(struct sock *sk, int size, int kind);
void __sk_mem_reduce_allocated(struct sock *sk, int amount);
void __sk_mem_reclaim(struct sock *sk, int amount);

#define SK_MEM_QUANTUM ((int)PAGE_SIZE)
Expand Down Expand Up @@ -1950,6 +1952,8 @@ void sk_reset_timer(struct sock *sk, struct timer_list *timer,

void sk_stop_timer(struct sock *sk, struct timer_list *timer);

int __sk_queue_drop_skb(struct sock *sk, struct sk_buff *skb,
unsigned int flags);
int __sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);

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36 changes: 22 additions & 14 deletions net/core/datagram.c
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Original file line number Diff line number Diff line change
Expand Up @@ -323,6 +323,27 @@ void __skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb, int len)
}
EXPORT_SYMBOL(__skb_free_datagram_locked);

int __sk_queue_drop_skb(struct sock *sk, struct sk_buff *skb,
unsigned int flags)
{
int err = 0;

if (flags & MSG_PEEK) {
err = -ENOENT;
spin_lock_bh(&sk->sk_receive_queue.lock);
if (skb == skb_peek(&sk->sk_receive_queue)) {
__skb_unlink(skb, &sk->sk_receive_queue);
atomic_dec(&skb->users);
err = 0;
}
spin_unlock_bh(&sk->sk_receive_queue.lock);
}

atomic_inc(&sk->sk_drops);
return err;
}
EXPORT_SYMBOL(__sk_queue_drop_skb);

/**
* skb_kill_datagram - Free a datagram skbuff forcibly
* @sk: socket
Expand All @@ -346,23 +367,10 @@ EXPORT_SYMBOL(__skb_free_datagram_locked);

int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags)
{
int err = 0;

if (flags & MSG_PEEK) {
err = -ENOENT;
spin_lock_bh(&sk->sk_receive_queue.lock);
if (skb == skb_peek(&sk->sk_receive_queue)) {
__skb_unlink(skb, &sk->sk_receive_queue);
atomic_dec(&skb->users);
err = 0;
}
spin_unlock_bh(&sk->sk_receive_queue.lock);
}
int err = __sk_queue_drop_skb(sk, skb, flags);

kfree_skb(skb);
atomic_inc(&sk->sk_drops);
sk_mem_reclaim_partial(sk);

return err;
}
EXPORT_SYMBOL(skb_kill_datagram);
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64 changes: 45 additions & 19 deletions net/core/sock.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2091,24 +2091,18 @@ int sk_wait_data(struct sock *sk, long *timeo, const struct sk_buff *skb)
EXPORT_SYMBOL(sk_wait_data);

/**
* __sk_mem_schedule - increase sk_forward_alloc and memory_allocated
* __sk_mem_raise_allocated - increase memory_allocated
* @sk: socket
* @size: memory size to allocate
* @amt: pages to allocate
* @kind: allocation type
*
* If kind is SK_MEM_SEND, it means wmem allocation. Otherwise it means
* rmem allocation. This function assumes that protocols which have
* memory_pressure use sk_wmem_queued as write buffer accounting.
* Similar to __sk_mem_schedule(), but does not update sk_forward_alloc
*/
int __sk_mem_schedule(struct sock *sk, int size, int kind)
int __sk_mem_raise_allocated(struct sock *sk, int size, int amt, int kind)
{
struct proto *prot = sk->sk_prot;
int amt = sk_mem_pages(size);
long allocated;

sk->sk_forward_alloc += amt * SK_MEM_QUANTUM;

allocated = sk_memory_allocated_add(sk, amt);
long allocated = sk_memory_allocated_add(sk, amt);

if (mem_cgroup_sockets_enabled && sk->sk_memcg &&
!mem_cgroup_charge_skmem(sk->sk_memcg, amt))
Expand Down Expand Up @@ -2169,28 +2163,47 @@ int __sk_mem_schedule(struct sock *sk, int size, int kind)

trace_sock_exceed_buf_limit(sk, prot, allocated);

/* Alas. Undo changes. */
sk->sk_forward_alloc -= amt * SK_MEM_QUANTUM;

sk_memory_allocated_sub(sk, amt);

if (mem_cgroup_sockets_enabled && sk->sk_memcg)
mem_cgroup_uncharge_skmem(sk->sk_memcg, amt);

return 0;
}
EXPORT_SYMBOL(__sk_mem_raise_allocated);

/**
* __sk_mem_schedule - increase sk_forward_alloc and memory_allocated
* @sk: socket
* @size: memory size to allocate
* @kind: allocation type
*
* If kind is SK_MEM_SEND, it means wmem allocation. Otherwise it means
* rmem allocation. This function assumes that protocols which have
* memory_pressure use sk_wmem_queued as write buffer accounting.
*/
int __sk_mem_schedule(struct sock *sk, int size, int kind)
{
int ret, amt = sk_mem_pages(size);

sk->sk_forward_alloc += amt << SK_MEM_QUANTUM_SHIFT;
ret = __sk_mem_raise_allocated(sk, size, amt, kind);
if (!ret)
sk->sk_forward_alloc -= amt << SK_MEM_QUANTUM_SHIFT;
return ret;
}
EXPORT_SYMBOL(__sk_mem_schedule);

/**
* __sk_mem_reclaim - reclaim memory_allocated
* __sk_mem_reduce_allocated - reclaim memory_allocated
* @sk: socket
* @amount: number of bytes (rounded down to a SK_MEM_QUANTUM multiple)
* @amount: number of quanta
*
* Similar to __sk_mem_reclaim(), but does not update sk_forward_alloc
*/
void __sk_mem_reclaim(struct sock *sk, int amount)
void __sk_mem_reduce_allocated(struct sock *sk, int amount)
{
amount >>= SK_MEM_QUANTUM_SHIFT;
sk_memory_allocated_sub(sk, amount);
sk->sk_forward_alloc -= amount << SK_MEM_QUANTUM_SHIFT;

if (mem_cgroup_sockets_enabled && sk->sk_memcg)
mem_cgroup_uncharge_skmem(sk->sk_memcg, amount);
Expand All @@ -2199,6 +2212,19 @@ void __sk_mem_reclaim(struct sock *sk, int amount)
(sk_memory_allocated(sk) < sk_prot_mem_limits(sk, 0)))
sk_leave_memory_pressure(sk);
}
EXPORT_SYMBOL(__sk_mem_reduce_allocated);

/**
* __sk_mem_reclaim - reclaim sk_forward_alloc and memory_allocated
* @sk: socket
* @amount: number of bytes (rounded down to a SK_MEM_QUANTUM multiple)
*/
void __sk_mem_reclaim(struct sock *sk, int amount)
{
amount >>= SK_MEM_QUANTUM_SHIFT;
sk->sk_forward_alloc -= amount << SK_MEM_QUANTUM_SHIFT;
__sk_mem_reduce_allocated(sk, amount);
}
EXPORT_SYMBOL(__sk_mem_reclaim);

int sk_set_peek_off(struct sock *sk, int val)
Expand Down

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