From: Willem de Bruijn <willemb@xxxxxxxxxx>
Add sock_omalloc and sock_ofree to be able to allocate control skbs,
for instance for looping errors onto sk_error_queue.
The transmit budget (sk_wmem_alloc) is involved in transmit skb
shaping, most notably in TCP Small Queues. Using this budget for
control packets would impact transmission.
Signed-off-by: Willem de Bruijn <willemb@xxxxxxxxxx>
---
include/net/sock.h | 2 ++
net/core/sock.c | 27 +++++++++++++++++++++++++++
2 files changed, 29 insertions(+)
diff --git a/include/net/sock.h b/include/net/sock.h
index 858891c36f94..6ab68442ceb9 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1524,6 +1524,8 @@ struct sk_buff *sock_wmalloc(struct sock *sk, unsigned long size, int force,
gfp_t priority);
void __sock_wfree(struct sk_buff *skb);
void sock_wfree(struct sk_buff *skb);
+struct sk_buff *sock_omalloc(struct sock *sk, unsigned long size,
+ gfp_t priority);
void skb_orphan_partial(struct sk_buff *skb);
void sock_rfree(struct sk_buff *skb);
void sock_efree(struct sk_buff *skb);
diff --git a/net/core/sock.c b/net/core/sock.c
index ad8a4bc84126..03261563f6a9 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1890,6 +1890,33 @@ struct sk_buff *sock_wmalloc(struct sock *sk, unsigned long size, int force,
}
EXPORT_SYMBOL(sock_wmalloc);
+static void sock_ofree(struct sk_buff *skb)
+{
+ struct sock *sk = skb->sk;
+
+ atomic_sub(skb->truesize, &sk->sk_omem_alloc);
+}
+
+struct sk_buff *sock_omalloc(struct sock *sk, unsigned long size,
+ gfp_t priority)
+{
+ struct sk_buff *skb;
+
+ /* small safe race: SKB_TRUESIZE may differ from final skb->truesize */
+ if (atomic_read(&sk->sk_omem_alloc) + SKB_TRUESIZE(size) >
+ sysctl_optmem_max)
+ return NULL;
+
+ skb = alloc_skb(size, priority);
+ if (!skb)
+ return NULL;
+
+ atomic_add(skb->truesize, &sk->sk_omem_alloc);
+ skb->sk = sk;
+ skb->destructor = sock_ofree;
+ return skb;
+}
+
/*
* Allocate a memory block from the socket's option memory buffer.
*/
--
2.13.1.518.g3df882009-goog
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