From a83045292daf9f07d0b103e5715ef527123d2fcc Mon Sep 17 00:00:00 2001 From: Ying Xue Date: Thu, 13 Feb 2014 17:29:17 -0500 Subject: [PATCH] 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/bcast.c | 1 - net/tipc/bearer.c | 16 +++------------- net/tipc/bearer.h | 5 +---- 3 files changed, 4 insertions(+), 18 deletions(-) diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c index af35f76c6b29..06a639c375f0 100644 --- a/net/tipc/bcast.c +++ b/net/tipc/bcast.c @@ -785,7 +785,6 @@ void tipc_bclink_init(void) bcl->owner = &bclink->node; bcl->max_pkt = MAX_PKT_DEFAULT_MCAST; tipc_link_set_queue_limits(bcl, BCLINK_WIN_DEFAULT); - spin_lock_init(&bcbearer->bearer.lock); bcl->b_ptr = &bcbearer->bearer; bcl->state = WORKING_WORKING; strlcpy(bcl->name, tipc_bclink_name, TIPC_MAX_LINK_NAME); diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c index 60caa45e5a41..242cddd35a47 100644 --- a/net/tipc/bearer.c +++ b/net/tipc/bearer.c @@ -327,7 +327,6 @@ restart: b_ptr->net_plane = bearer_id + 'A'; b_ptr->active = 1; b_ptr->priority = priority; - spin_lock_init(&b_ptr->lock); res = tipc_disc_create(b_ptr, &b_ptr->bcast_addr, disc_domain); if (res) { @@ -351,9 +350,7 @@ static int tipc_reset_bearer(struct tipc_bearer *b_ptr) { read_lock_bh(&tipc_net_lock); pr_info("Resetting bearer <%s>\n", b_ptr->name); - spin_lock_bh(&b_ptr->lock); tipc_link_reset_list(b_ptr->identity); - spin_unlock_bh(&b_ptr->lock); read_unlock_bh(&tipc_net_lock); return 0; } @@ -365,19 +362,12 @@ static int tipc_reset_bearer(struct tipc_bearer *b_ptr) */ static void bearer_disable(struct tipc_bearer *b_ptr, bool shutting_down) { - struct tipc_link_req *temp_req; - pr_info("Disabling bearer <%s>\n", b_ptr->name); - spin_lock_bh(&b_ptr->lock); b_ptr->media->disable_media(b_ptr); + tipc_link_delete_list(b_ptr->identity, shutting_down); - temp_req = b_ptr->link_req; - b_ptr->link_req = NULL; - spin_unlock_bh(&b_ptr->lock); - - if (temp_req) - tipc_disc_delete(temp_req); - + if (b_ptr->link_req) + tipc_disc_delete(b_ptr->link_req); memset(b_ptr, 0, sizeof(struct tipc_bearer)); } 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;