From db82476f37413eaeff5f836a9d8b022d6544accf Mon Sep 17 00:00:00 2001 From: =?utf8?q?H=C3=A5kon=20Bugge?= Date: Wed, 18 Apr 2018 16:24:50 +0200 Subject: [PATCH] IB/core: Make ib_mad_client_id atomic MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Currently, the kernel protects access to the agent ID allocator on a per port basis using a spinlock, so it is impossible for two apps/threads on the same port to get the same TID, but it is entirely possible for two threads on different ports to end up with the same TID. As this can be confusing (regardless of it being legal according to the IB Spec 1.3, C13-18.1.1, in section 13.4.6.4 - TransactionID usage), and as the rdma-core user space API for /dev/umad devices implies unique TIDs even across ports, make the TID an atomic type so that no two allocations, regardless of port number, will be the same. Signed-off-by: HÃ¥kon Bugge Reviewed-by: Jack Morgenstein Reviewed-by: Ira Weiny Reviewed-by: Zhu Yanjun Signed-off-by: Doug Ledford --- drivers/infiniband/core/mad.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/infiniband/core/mad.c b/drivers/infiniband/core/mad.c index c50596f7f98a..b28452a55a08 100644 --- a/drivers/infiniband/core/mad.c +++ b/drivers/infiniband/core/mad.c @@ -59,7 +59,7 @@ module_param_named(recv_queue_size, mad_recvq_size, int, 0444); MODULE_PARM_DESC(recv_queue_size, "Size of receive queue in number of work requests"); static struct list_head ib_mad_port_list; -static u32 ib_mad_client_id = 0; +static atomic_t ib_mad_client_id = ATOMIC_INIT(0); /* Port list lock */ static DEFINE_SPINLOCK(ib_mad_port_list_lock); @@ -377,7 +377,7 @@ struct ib_mad_agent *ib_register_mad_agent(struct ib_device *device, } spin_lock_irqsave(&port_priv->reg_lock, flags); - mad_agent_priv->agent.hi_tid = ++ib_mad_client_id; + mad_agent_priv->agent.hi_tid = atomic_inc_return(&ib_mad_client_id); /* * Make sure MAD registration (if supplied) -- 2.30.2