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authorSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>2014-03-11 02:09:39 +0530
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2014-03-20 13:43:44 +0100
commitbc0003c93f0e68b5383fb36579f7efa267b7dc16 (patch)
tree8f8434edd45a45109d4a2d7c8b9ca0c775895f3b /drivers/scsi
parent009f225ef050d231ebb7b87264a21a7daac0f175 (diff)
scsi, bnx2i: Fix CPU hotplug callback registration
Subsystems that want to register CPU hotplug callbacks, as well as perform initialization for the CPUs that are already online, often do it as shown below: get_online_cpus(); for_each_online_cpu(cpu) init_cpu(cpu); register_cpu_notifier(&foobar_cpu_notifier); put_online_cpus(); This is wrong, since it is prone to ABBA deadlocks involving the cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently with CPU hotplug operations). Instead, the correct and race-free way of performing the callback registration is: cpu_notifier_register_begin(); for_each_online_cpu(cpu) init_cpu(cpu); /* Note the use of the double underscored version of the API */ __register_cpu_notifier(&foobar_cpu_notifier); cpu_notifier_register_done(); Fix the bnx2i code in scsi by using this latter form of callback registration. Cc: Eddie Wai <eddie.wai@broadcom.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/scsi')
-rw-r--r--drivers/scsi/bnx2i/bnx2i_init.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/drivers/scsi/bnx2i/bnx2i_init.c b/drivers/scsi/bnx2i/bnx2i_init.c
index 34c294b42c84..80c03b452d61 100644
--- a/drivers/scsi/bnx2i/bnx2i_init.c
+++ b/drivers/scsi/bnx2i/bnx2i_init.c
@@ -537,11 +537,15 @@ static int __init bnx2i_mod_init(void)
p->iothread = NULL;
}
+ cpu_notifier_register_begin();
+
for_each_online_cpu(cpu)
bnx2i_percpu_thread_create(cpu);
/* Initialize per CPU interrupt thread */
- register_hotcpu_notifier(&bnx2i_cpu_notifier);
+ __register_hotcpu_notifier(&bnx2i_cpu_notifier);
+
+ cpu_notifier_register_done();
return 0;
@@ -581,11 +585,15 @@ static void __exit bnx2i_mod_exit(void)
}
mutex_unlock(&bnx2i_dev_lock);
- unregister_hotcpu_notifier(&bnx2i_cpu_notifier);
+ cpu_notifier_register_begin();
for_each_online_cpu(cpu)
bnx2i_percpu_thread_destroy(cpu);
+ __unregister_hotcpu_notifier(&bnx2i_cpu_notifier);
+
+ cpu_notifier_register_done();
+
iscsi_unregister_transport(&bnx2i_iscsi_transport);
cnic_unregister_driver(CNIC_ULP_ISCSI);
}