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| author | Ying Xue <ying.xue@windriver.com> | 2014-04-28 18:00:10 +0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-04-28 14:49:54 -0400 |
| commit | eab8c045732635e3833a5d58b17c6da08ff71f9e (patch) | |
| tree | 8bd9c3e5aaee575abef950d992e92511bdc5f2b8 /net/tipc/name_distr.c | |
| parent | d7bb74c38cb3de40600dcbba50a4f84df290dc91 (diff) | |
| download | linux-eab8c045732635e3833a5d58b17c6da08ff71f9e.tar.gz linux-eab8c045732635e3833a5d58b17c6da08ff71f9e.tar.bz2 linux-eab8c045732635e3833a5d58b17c6da08ff71f9e.zip | |
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/name_distr.c')
| -rw-r--r-- | net/tipc/name_distr.c | 18 |
1 files changed, 9 insertions, 9 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; } /* |