From c61dd61dec0b79fa22ded8b5caf2e817dc506c24 Mon Sep 17 00:00:00 2001 From: Ying Xue Date: Thu, 13 Feb 2014 17:29:09 -0500 Subject: tipc: remove 'links' list from tipc_bearer struct In our ongoing effort to simplify the TIPC locking structure, we see a need to remove the linked list for tipc_links in the bearer. This can be explained as follows. Currently, we have three different ways to access a link, via three different lists/tables: 1: Via a node hash table: Used by the time-critical outgoing/incoming data paths. (e.g. link_send_sections_fast() and tipc_recv_msg() ): grab net_lock(read) find node from node hash table grab node_lock select link grab bearer_lock send_msg() release bearer_lock release node lock release net_lock 2: Via a global linked list for nodes: Used by configuration commands (link_cmd_set_value()) grab net_lock(read) find node and link from global node list (using link name) grab node_lock update link release node lock release net_lock (Same locking order as above. No problem.) 3: Via the bearer's linked link list: Used by notifications from interface (e.g. tipc_disable_bearer() ) grab net_lock(write) grab bearer_lock get link ptr from bearer's link list get node from link grab node_lock delete link release node lock release bearer_lock release net_lock (Different order from above, but works because we grab the outer net_lock in write mode first, excluding all other access.) The first major goal in our simplification effort is to get rid of the "big" net_lock, replacing it with rcu-locks when accessing the node list and node hash array. This will come in a later patch series. But to get there we first need to rewrite access methods ##2 and 3, since removal of net_lock would introduce three major problems: a) In access method #2, we access the link before taking the protecting node_lock. This will not work once net_lock is gone, so we will have to change the access order. We will deal with this in a later commit in this series, "tipc: add node lock protection to link found by link_find_link()". b) When the outer protection from net_lock is gone, taking bearer_lock and node_lock in opposite order of method 1) and 2) will become an obvious deadlock hazard. This is fixed in the commit ("tipc: remove bearer_lock from tipc_bearer struct") later in this series. c) Similar to what is described in problem a), access method #3 starts with using a link pointer that is unprotected by node_lock, in order to via that pointer find the correct node struct and lock it. Before we remove net_lock, this access order must be altered. This is what we do with this commit. We can avoid introducing problem problem c) by even here using the global node list to find the node, before accessing its links. When we loop though the node list we use the own bearer identity as search criteria, thus easily finding the links that are associated to the resetting/disabling bearer. It should be noted that although this method is somewhat slower than the current list traversal, it is in no way time critical. This is only about resetting or deleting links, something that must be considered relatively infrequent events. As a bonus, we can get rid of the mutual pointers between links and bearers. After this commit, pointer dependency go in one direction only: from the link to the bearer. This commit pre-empts introduction of problem c) as described above. Signed-off-by: Ying Xue Reviewed-by: Paul Gortmaker Signed-off-by: Jon Maloy Signed-off-by: David S. Miller --- net/tipc/bearer.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'net/tipc/bearer.h') diff --git a/net/tipc/bearer.h b/net/tipc/bearer.h index 4f5db9ad5bf6..647cb1d2324a 100644 --- a/net/tipc/bearer.h +++ b/net/tipc/bearer.h @@ -120,7 +120,6 @@ struct tipc_media { * @tolerance: default link tolerance for bearer * @identity: array index of this bearer within TIPC bearer array * @link_req: ptr to (optional) structure making periodic link setup requests - * @links: list of non-congested links associated with bearer * @active: non-zero if bearer structure is represents a bearer * @net_plane: network plane ('A' through 'H') currently associated with bearer * @nodes: indicates which nodes in cluster can be reached through bearer @@ -142,7 +141,6 @@ struct tipc_bearer { u32 tolerance; u32 identity; struct tipc_link_req *link_req; - struct list_head links; int active; char net_plane; struct tipc_node_map nodes; -- cgit From a83045292daf9f07d0b103e5715ef527123d2fcc Mon Sep 17 00:00:00 2001 From: Ying Xue Date: Thu, 13 Feb 2014 17:29:17 -0500 Subject: tipc: remove bearer_lock from tipc_bearer struct MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit After the earlier commits ("tipc: remove 'links' list from tipc_bearer struct") and ("tipc: introduce new spinlock to protect struct link_req"), there is no longer any need to protect struct link_req or or any link list by use of bearer_lock. Furthermore, we have eliminated the need for using bearer_lock during downcalls (send) from the link to the bearer, since we have ensured that bearers always have a longer life cycle that their associated links, and always contain valid data. So, the only need now for a lock protecting bearers is for guaranteeing consistency of the bearer list itself. For this, it is sufficient, at least for the time being, to continue applying 'net_lock´ in write mode. By removing bearer_lock we also pre-empt introduction of issue b) descibed in the previous commit "tipc: remove 'links' list from tipc_bearer struct": "b) When the outer protection from net_lock is gone, taking bearer_lock and node_lock in opposite order of method 1) and 2) will become an obvious deadlock hazard". Therefore, we now eliminate the bearer_lock spinlock. Signed-off-by: Ying Xue Reviewed-by: Paul Gortmaker Signed-off-by: Jon Maloy Signed-off-by: David S. Miller --- net/tipc/bearer.h | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'net/tipc/bearer.h') diff --git a/net/tipc/bearer.h b/net/tipc/bearer.h index 647cb1d2324a..425dd8107a8f 100644 --- a/net/tipc/bearer.h +++ b/net/tipc/bearer.h @@ -107,10 +107,8 @@ struct tipc_media { /** * struct tipc_bearer - Generic TIPC bearer structure - * @dev: ptr to associated network device - * @usr_handle: pointer to additional media-specific information about bearer + * @media_ptr: pointer to additional media-specific information about bearer * @mtu: max packet size bearer can support - * @lock: spinlock for controlling access to bearer * @addr: media-specific address associated with bearer * @name: bearer name (format = media:interface) * @media: ptr to media structure associated with bearer @@ -133,7 +131,6 @@ struct tipc_bearer { u32 mtu; /* initalized by media */ struct tipc_media_addr addr; /* initalized by media */ char name[TIPC_MAX_BEARER_NAME]; - spinlock_t lock; struct tipc_media *media; struct tipc_media_addr bcast_addr; u32 priority; -- cgit From 3874ccbba80f3b3127e94b1e055fb3d502a44718 Mon Sep 17 00:00:00 2001 From: Ying Xue Date: Thu, 27 Mar 2014 12:54:33 +0800 Subject: tipc: convert tipc_bearers array to pointer list As part of the effort to introduce RCU protection for the bearer list, we first need to change it to a list of pointers. Signed-off-by: Ying Xue Reviewed-by: Erik Hugne Reviewed-by: Jon Maloy Signed-off-by: David S. Miller --- net/tipc/bearer.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/tipc/bearer.h') diff --git a/net/tipc/bearer.h b/net/tipc/bearer.h index 425dd8107a8f..f4e72caccb21 100644 --- a/net/tipc/bearer.h +++ b/net/tipc/bearer.h @@ -150,7 +150,7 @@ struct tipc_bearer_names { struct tipc_link; -extern struct tipc_bearer tipc_bearers[]; +extern struct tipc_bearer *bearer_list[]; /* * TIPC routines available to supported media types -- cgit From f47de12b06c95cfc38c1c79986210c7620f264c4 Mon Sep 17 00:00:00 2001 From: Ying Xue Date: Thu, 27 Mar 2014 12:54:34 +0800 Subject: tipc: remove active flag from tipc_bearer structure After the allocation of tipc_bearer structure instance is converted from statical way to dynamical way, we identify whether a certain tipc_bearer structure pointer is valid by checking whether the pointer is NULL or not. So the active flag in tipc_bearer structure becomes redundant. Signed-off-by: Ying Xue Reviewed-by: Erik Hugne Reviewed-by: Jon Maloy Signed-off-by: David S. Miller --- net/tipc/bearer.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'net/tipc/bearer.h') diff --git a/net/tipc/bearer.h b/net/tipc/bearer.h index f4e72caccb21..3f6d7d0f059b 100644 --- a/net/tipc/bearer.h +++ b/net/tipc/bearer.h @@ -118,7 +118,6 @@ struct tipc_media { * @tolerance: default link tolerance for bearer * @identity: array index of this bearer within TIPC bearer array * @link_req: ptr to (optional) structure making periodic link setup requests - * @active: non-zero if bearer structure is represents a bearer * @net_plane: network plane ('A' through 'H') currently associated with bearer * @nodes: indicates which nodes in cluster can be reached through bearer * @@ -138,7 +137,6 @@ struct tipc_bearer { u32 tolerance; u32 identity; struct tipc_link_req *link_req; - int active; char net_plane; struct tipc_node_map nodes; }; -- cgit From a21a584d6720ce349b05795b9bcfab3de8e58419 Mon Sep 17 00:00:00 2001 From: Erik Hugne Date: Fri, 28 Mar 2014 10:32:08 +0100 Subject: tipc: fix neighbor detection problem after hw address change If the hardware address of a underlying netdevice is changed, it is not enough to simply reset the bearer/links over this device. We also need to reflect this change in the TIPC bearer and node discovery structures aswell. This patch adds the necessary reinitialization of the node disovery mechanism following a hardware address change so that the correct originating media address is advertised in the discovery messages. Signed-off-by: Erik Hugne Reported-by: Dong Liu Reviewed-by: Ying Xue Signed-off-by: David S. Miller --- net/tipc/bearer.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/tipc/bearer.h') diff --git a/net/tipc/bearer.h b/net/tipc/bearer.h index 3f6d7d0f059b..ba48145e871d 100644 --- a/net/tipc/bearer.h +++ b/net/tipc/bearer.h @@ -116,6 +116,7 @@ struct tipc_media { * @priority: default link priority for bearer * @window: default window size for bearer * @tolerance: default link tolerance for bearer + * @domain: network domain to which links can be established * @identity: array index of this bearer within TIPC bearer array * @link_req: ptr to (optional) structure making periodic link setup requests * @net_plane: network plane ('A' through 'H') currently associated with bearer @@ -135,6 +136,7 @@ struct tipc_bearer { u32 priority; u32 window; u32 tolerance; + u32 domain; u32 identity; struct tipc_link_req *link_req; char net_plane; -- cgit