From: Florian Westphal <fw@strlen.de>
Date: Sat, 16 May 2020 08:46:23 +0000 (+0200)
Subject: net: allow __skb_ext_alloc to sleep
X-Git-Tag: v5.8-rc1~165^2~164^2
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=4930f4831b1547b52c5968e9307fe3d840d7fba0;p=linux-2.6-block.git

net: allow __skb_ext_alloc to sleep

mptcp calls this from the transmit side, from process context.
Allow a sleeping allocation instead of unconditional GFP_ATOMIC.

Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 3000c526f552..531843952809 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -4165,7 +4165,7 @@ struct skb_ext {
 	char data[] __aligned(8);
 };
 
-struct skb_ext *__skb_ext_alloc(void);
+struct skb_ext *__skb_ext_alloc(gfp_t flags);
 void *__skb_ext_set(struct sk_buff *skb, enum skb_ext_id id,
 		    struct skb_ext *ext);
 void *skb_ext_add(struct sk_buff *skb, enum skb_ext_id id);
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 1bf0c3d278e7..35a133c6d13b 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -6087,13 +6087,15 @@ static void *skb_ext_get_ptr(struct skb_ext *ext, enum skb_ext_id id)
 /**
  * __skb_ext_alloc - allocate a new skb extensions storage
  *
+ * @flags: See kmalloc().
+ *
  * Returns the newly allocated pointer. The pointer can later attached to a
  * skb via __skb_ext_set().
  * Note: caller must handle the skb_ext as an opaque data.
  */
-struct skb_ext *__skb_ext_alloc(void)
+struct skb_ext *__skb_ext_alloc(gfp_t flags)
 {
-	struct skb_ext *new = kmem_cache_alloc(skbuff_ext_cache, GFP_ATOMIC);
+	struct skb_ext *new = kmem_cache_alloc(skbuff_ext_cache, flags);
 
 	if (new) {
 		memset(new->offset, 0, sizeof(new->offset));
@@ -6188,7 +6190,7 @@ void *skb_ext_add(struct sk_buff *skb, enum skb_ext_id id)
 	} else {
 		newoff = SKB_EXT_CHUNKSIZEOF(*new);
 
-		new = __skb_ext_alloc();
+		new = __skb_ext_alloc(GFP_ATOMIC);
 		if (!new)
 			return NULL;
 	}
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index bc950cf818f7..e3a628bea2b8 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -367,8 +367,10 @@ static void mptcp_stop_timer(struct sock *sk)
 
 static bool mptcp_ext_cache_refill(struct mptcp_sock *msk)
 {
+	const struct sock *sk = (const struct sock *)msk;
+
 	if (!msk->cached_ext)
-		msk->cached_ext = __skb_ext_alloc();
+		msk->cached_ext = __skb_ext_alloc(sk->sk_allocation);
 
 	return !!msk->cached_ext;
 }