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>
diff --git a/net/core/sock.c b/net/core/sock.c
index 5a6a906..0c67fac 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -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 @@
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 @@
}
}
- 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 @@
{
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 @@
}
}
- 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 @@
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 @@
#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_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)