Commit e96f78ab authored Oct 03, 2015 by Eric Dumazet Committed by David S. Miller Oct 03, 2015

tcp/dccp: add SLAB_DESTROY_BY_RCU flag for request sockets



Before letting request sockets being put in TCP/DCCP regular
ehash table, we need to add either :

- SLAB_DESTROY_BY_RCU flag to their kmem_cache
- add RCU grace period before freeing them.

Since we carefully respected the SLAB_DESTROY_BY_RCU protocol
like ESTABLISH and TIMEWAIT sockets, use it here.

req_prot_init() being only used by TCP and DCCP, I did not add
a new slab_flags into their rsk_prot, but reuse prot->slab_flags

Since all reqsk_alloc() users are correctly dealing with a failure,
add the __GFP_NOWARN flag to avoid traces under pressure.

Fixes: 079096f1 ("tcp/dccp: install syn_recv requests into ehash table")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 4236e2a1

include/net/request_sock.h

+3 −1

Original line number	Diff line number	Diff line
		@@ -82,7 +82,9 @@ static inline struct sock req_to_sk(struct request_sock req)
		static inline struct request_sock *
		reqsk_alloc(const struct request_sock_ops ops, struct sock sk_listener)
		{
		struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC);
		struct request_sock *req;

		req = kmem_cache_alloc(ops->slab, GFP_ATOMIC \| __GFP_NOWARN);

		if (req) {
		req->rsk_ops = ops;

net/core/sock.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -2758,7 +2758,7 @@ static int req_prot_init(const struct proto *prot)

		rsk_prot->slab = kmem_cache_create(rsk_prot->slab_name,
		rsk_prot->obj_size, 0,
		0, NULL);
		prot->slab_flags, NULL);

		if (!rsk_prot->slab) {
		pr_crit("%s: Can't create request sock SLAB cache!\n",