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authorYing Xue <ying.xue@windriver.com>2014-04-28 18:00:10 +0800
committerDavid S. Miller <davem@davemloft.net>2014-04-28 14:49:54 -0400
commiteab8c045732635e3833a5d58b17c6da08ff71f9e (patch)
tree8bd9c3e5aaee575abef950d992e92511bdc5f2b8 /net/tipc
parentd7bb74c38cb3de40600dcbba50a4f84df290dc91 (diff)
tipc: move the delivery of named messages out of nametbl lock
Commit a89778d8baf19cd7e728d81121a294a06cedaad1 ("tipc: add support for link state subscriptions") introduced below possible deadlock scenario: CPU0 CPU1 T0: tipc_publish() link_timeout() T1: tipc_nametbl_publish() [grab node lock]* T2: [grab nametbl write lock]* link_state_event() T3: named_cluster_distribute() link_activate() T4: [grab node lock]* tipc_node_link_up() T5: tipc_nametbl_publish() T6: [grab nametble write lock]* The opposite order of holding nametbl write lock and node lock on above two different paths may result in a deadlock. If we move the the delivery of named messages via link out of name nametbl lock, the reverse order of holding locks will be eliminated, as a result, the deadlock will be killed as well. Signed-off-by: Ying Xue <ying.xue@windriver.com> Reviewed-by: Erik Hugne <erik.hugne@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tipc')
-rw-r--r--net/tipc/name_distr.c18
-rw-r--r--net/tipc/name_distr.h5
-rw-r--r--net/tipc/name_table.c12
3 files changed, 22 insertions, 13 deletions
diff --git a/net/tipc/name_distr.c b/net/tipc/name_distr.c
index 36a72822601c..974a73f3d876 100644
--- a/net/tipc/name_distr.c
+++ b/net/tipc/name_distr.c
@@ -127,7 +127,7 @@ static struct sk_buff *named_prepare_buf(u32 type, u32 size, u32 dest)
return buf;
}
-static void named_cluster_distribute(struct sk_buff *buf)
+void named_cluster_distribute(struct sk_buff *buf)
{
struct sk_buff *buf_copy;
struct tipc_node *n_ptr;
@@ -156,7 +156,7 @@ static void named_cluster_distribute(struct sk_buff *buf)
/**
* tipc_named_publish - tell other nodes about a new publication by this node
*/
-void tipc_named_publish(struct publication *publ)
+struct sk_buff *tipc_named_publish(struct publication *publ)
{
struct sk_buff *buf;
struct distr_item *item;
@@ -165,23 +165,23 @@ void tipc_named_publish(struct publication *publ)
publ_lists[publ->scope]->size++;
if (publ->scope == TIPC_NODE_SCOPE)
- return;
+ return NULL;
buf = named_prepare_buf(PUBLICATION, ITEM_SIZE, 0);
if (!buf) {
pr_warn("Publication distribution failure\n");
- return;
+ return NULL;
}
item = (struct distr_item *)msg_data(buf_msg(buf));
publ_to_item(item, publ);
- named_cluster_distribute(buf);
+ return buf;
}
/**
* tipc_named_withdraw - tell other nodes about a withdrawn publication by this node
*/
-void tipc_named_withdraw(struct publication *publ)
+struct sk_buff *tipc_named_withdraw(struct publication *publ)
{
struct sk_buff *buf;
struct distr_item *item;
@@ -190,17 +190,17 @@ void tipc_named_withdraw(struct publication *publ)
publ_lists[publ->scope]->size--;
if (publ->scope == TIPC_NODE_SCOPE)
- return;
+ return NULL;
buf = named_prepare_buf(WITHDRAWAL, ITEM_SIZE, 0);
if (!buf) {
pr_warn("Withdrawal distribution failure\n");
- return;
+ return NULL;
}
item = (struct distr_item *)msg_data(buf_msg(buf));
publ_to_item(item, publ);
- named_cluster_distribute(buf);
+ return buf;
}
/*
diff --git a/net/tipc/name_distr.h b/net/tipc/name_distr.h
index 9b312ccfd43e..47ff829f9361 100644
--- a/net/tipc/name_distr.h
+++ b/net/tipc/name_distr.h
@@ -39,8 +39,9 @@
#include "name_table.h"
-void tipc_named_publish(struct publication *publ);
-void tipc_named_withdraw(struct publication *publ);
+struct sk_buff *tipc_named_publish(struct publication *publ);
+struct sk_buff *tipc_named_withdraw(struct publication *publ);
+void named_cluster_distribute(struct sk_buff *buf);
void tipc_named_node_up(unsigned long node);
void tipc_named_rcv(struct sk_buff *buf);
void tipc_named_reinit(void);
diff --git a/net/tipc/name_table.c b/net/tipc/name_table.c
index 042e8e3cabc0..9bcf4b58853f 100644
--- a/net/tipc/name_table.c
+++ b/net/tipc/name_table.c
@@ -664,6 +664,7 @@ struct publication *tipc_nametbl_publish(u32 type, u32 lower, u32 upper,
u32 scope, u32 port_ref, u32 key)
{
struct publication *publ;
+ struct sk_buff *buf = NULL;
if (table.local_publ_count >= TIPC_MAX_PUBLICATIONS) {
pr_warn("Publication failed, local publication limit reached (%u)\n",
@@ -676,9 +677,12 @@ struct publication *tipc_nametbl_publish(u32 type, u32 lower, u32 upper,
tipc_own_addr, port_ref, key);
if (likely(publ)) {
table.local_publ_count++;
- tipc_named_publish(publ);
+ buf = tipc_named_publish(publ);
}
write_unlock_bh(&tipc_nametbl_lock);
+
+ if (buf)
+ named_cluster_distribute(buf);
return publ;
}
@@ -688,15 +692,19 @@ struct publication *tipc_nametbl_publish(u32 type, u32 lower, u32 upper,
int tipc_nametbl_withdraw(u32 type, u32 lower, u32 ref, u32 key)
{
struct publication *publ;
+ struct sk_buff *buf;
write_lock_bh(&tipc_nametbl_lock);
publ = tipc_nametbl_remove_publ(type, lower, tipc_own_addr, ref, key);
if (likely(publ)) {
table.local_publ_count--;
- tipc_named_withdraw(publ);
+ buf = tipc_named_withdraw(publ);
write_unlock_bh(&tipc_nametbl_lock);
list_del_init(&publ->pport_list);
kfree(publ);
+
+ if (buf)
+ named_cluster_distribute(buf);
return 1;
}
write_unlock_bh(&tipc_nametbl_lock);