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net: fix sleeping while atomic problem in sock mem_cgroup. 

We can't scan the proto_list to initialize sock cgroups, as it
holds a rwlock, and we also want to keep the code generic enough to
avoid calling the initialization functions of protocols directly,

Convert proto_list_lock into a mutex, so we can sleep and do the
necessary allocations. This lock is seldom taken, so there shouldn't
be any performance penalties associated with that

Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Hiroyouki Kamezawa <kamezawa.hiroyu@jp.fujitsu.com>
CC: David S. Miller <davem@davemloft.net>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Stephen Rothwell <sfr@canb.auug.org.au>
CC: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Glauber Costa 2011-12-16 00:51:59 +00:00 committed by David S. Miller
parent cb9ffb7694
commit 36b77a5208
1 changed files with 14 additions and 14 deletions
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28
net/core/sock.c
View File

@ -136,7 +136,7 @@
#include <net/tcp.h>
#endif
static DEFINE_RWLOCK(proto_list_lock);
static DEFINE_MUTEX(proto_list_mutex);
static LIST_HEAD(proto_list);
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
@ -145,7 +145,7 @@ int mem_cgroup_sockets_init(struct cgroup *cgrp, struct cgroup_subsys *ss)
struct proto *proto;
int ret = 0;
read_lock(&proto_list_lock);
mutex_lock(&proto_list_mutex);
list_for_each_entry(proto, &proto_list, node) {
if (proto->init_cgroup) {
ret = proto->init_cgroup(cgrp, ss);
@ -154,13 +154,13 @@ int mem_cgroup_sockets_init(struct cgroup *cgrp, struct cgroup_subsys *ss)
}
}
read_unlock(&proto_list_lock);
mutex_unlock(&proto_list_mutex);
return ret;
out:
list_for_each_entry_continue_reverse(proto, &proto_list, node)
if (proto->destroy_cgroup)
proto->destroy_cgroup(cgrp, ss);
read_unlock(&proto_list_lock);
mutex_unlock(&proto_list_mutex);
return ret;
}
@ -168,11 +168,11 @@ void mem_cgroup_sockets_destroy(struct cgroup *cgrp, struct cgroup_subsys *ss)
{
struct proto *proto;
read_lock(&proto_list_lock);
mutex_lock(&proto_list_mutex);
list_for_each_entry_reverse(proto, &proto_list, node)
if (proto->destroy_cgroup)
proto->destroy_cgroup(cgrp, ss);
read_unlock(&proto_list_lock);
mutex_unlock(&proto_list_mutex);
}
#endif
@ -2479,10 +2479,10 @@ int proto_register(struct proto *prot, int alloc_slab)
}
}
write_lock(&proto_list_lock);
mutex_lock(&proto_list_mutex);
list_add(&prot->node, &proto_list);
assign_proto_idx(prot);
write_unlock(&proto_list_lock);
mutex_unlock(&proto_list_mutex);
return 0;
out_free_timewait_sock_slab_name:
@ -2505,10 +2505,10 @@ EXPORT_SYMBOL(proto_register);
void proto_unregister(struct proto *prot)
{
write_lock(&proto_list_lock);
mutex_lock(&proto_list_mutex);
release_proto_idx(prot);
list_del(&prot->node);
write_unlock(&proto_list_lock);
mutex_unlock(&proto_list_mutex);
if (prot->slab != NULL) {
kmem_cache_destroy(prot->slab);
@ -2531,9 +2531,9 @@ EXPORT_SYMBOL(proto_unregister);
#ifdef CONFIG_PROC_FS
static void *proto_seq_start(struct seq_file *seq, loff_t *pos)
__acquires(proto_list_lock)
__acquires(proto_list_mutex)
{
read_lock(&proto_list_lock);
mutex_lock(&proto_list_mutex);
return seq_list_start_head(&proto_list, *pos);
}
@ -2543,9 +2543,9 @@ static void *proto_seq_next(struct seq_file *seq, void *v, loff_t *pos)
}
static void proto_seq_stop(struct seq_file *seq, void *v)
__releases(proto_list_lock)
__releases(proto_list_mutex)
{
read_unlock(&proto_list_lock);
mutex_unlock(&proto_list_mutex);
}
static char proto_method_implemented(const void *method)