diff options
| -rw-r--r-- | drivers/hv/channel_mgmt.c | 46 |
1 files changed, 18 insertions, 28 deletions
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c index fde806d6525b..89eaacf069a8 100644 --- a/drivers/hv/channel_mgmt.c +++ b/drivers/hv/channel_mgmt.c @@ -554,26 +554,34 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel) bool fnew = true; /* - * Initialize the target_CPU before inserting the channel in - * the chn_list and sc_list lists, within the channel_mutex - * critical section: + * Synchronize vmbus_process_offer() and CPU hotplugging: * * CPU1 CPU2 * - * [vmbus_process_offer()] [hv_syninc_cleanup()] + * [vmbus_process_offer()] [Hot removal of the CPU] * - * STORE target_cpu LOCK channel_mutex - * LOCK channel_mutex SEARCH chn_list - * INSERT chn_list LOAD target_cpu - * UNLOCK channel_mutex UNLOCK channel_mutex + * CPU_READ_LOCK CPUS_WRITE_LOCK + * LOAD cpu_online_mask SEARCH chn_list + * STORE target_cpu LOAD target_cpu + * INSERT chn_list STORE cpu_online_mask + * CPUS_READ_UNLOCK CPUS_WRITE_UNLOCK + * + * Forbids: CPU1's LOAD from *not* seing CPU2's STORE && + * CPU2's SEARCH from *not* seeing CPU1's INSERT * * Forbids: CPU2's SEARCH from seeing CPU1's INSERT && * CPU2's LOAD from *not* seing CPU1's STORE */ - init_vp_index(newchannel, hv_get_dev_type(newchannel)); + cpus_read_lock(); + /* + * Serializes the modifications of the chn_list list as well as + * the accesses to next_numa_node_id in init_vp_index(). + */ mutex_lock(&vmbus_connection.channel_mutex); + init_vp_index(newchannel, hv_get_dev_type(newchannel)); + /* Remember the channels that should be cleaned up upon suspend. */ if (is_hvsock_channel(newchannel) || is_sub_channel(newchannel)) atomic_inc(&vmbus_connection.nr_chan_close_on_suspend); @@ -623,6 +631,7 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel) vmbus_channel_map_relid(newchannel); mutex_unlock(&vmbus_connection.channel_mutex); + cpus_read_unlock(); /* * vmbus_process_offer() mustn't call channel->sc_creation_callback() @@ -655,13 +664,6 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel) * We use this state to statically distribute the channel interrupt load. */ static int next_numa_node_id; -/* - * init_vp_index() accesses global variables like next_numa_node_id, and - * it can run concurrently for primary channels and sub-channels: see - * vmbus_process_offer(), so we need the lock to protect the global - * variables. - */ -static DEFINE_SPINLOCK(bind_channel_to_cpu_lock); /* * Starting with Win8, we can statically distribute the incoming @@ -700,15 +702,6 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type) return; } - /* No CPUs can come up or down during this. */ - cpus_read_lock(); - - /* - * Serializes the accesses to the global variable next_numa_node_id. - * See also the header comment of the spin lock declaration. - */ - spin_lock(&bind_channel_to_cpu_lock); - while (true) { numa_node = next_numa_node_id++; if (numa_node == nr_node_ids) { @@ -739,9 +732,6 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type) channel->target_cpu = target_cpu; channel->target_vp = hv_cpu_number_to_vp_number(target_cpu); - spin_unlock(&bind_channel_to_cpu_lock); - cpus_read_unlock(); - free_cpumask_var(available_mask); } |