[patch V2 07/24] KVM/PPC/Book3S HV: Use cpuhp_setup_state_nocalls_cpuslocked()

Thomas Gleixner
2017-04-18T19:53:38Z

[-- Attachment #1: KVMPPCBook3S_HV_Use_cpuhp_setup_state_nocalls_locked.patch --]
[-- Type: text/plain, Size: 1310 bytes --]

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

kvmppc_alloc_host_rm_ops() holds get_online_cpus() while invoking
cpuhp_setup_state_nocalls().

cpuhp_setup_state_nocalls() invokes get_online_cpus() as well. This is
correct, but prevents the conversion of the hotplug locking to a percpu
rwsem.

Use cpuhp_setup_state_nocalls_cpuslocked() to avoid the nested call.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexander Graf <agraf@suse.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: kvm@vger.kernel.org
Cc: kvm-ppc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org

---
arch/powerpc/kvm/book3s_hv.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -3336,10 +3336,10 @@ void kvmppc_alloc_host_rm_ops(void)
return;
}

- cpuhp_setup_state_nocalls(CPUHP_KVM_PPC_BOOK3S_PREPARE,
- "ppc/kvm_book3s:prepare",
- kvmppc_set_host_core,
- kvmppc_clear_host_core);
+ cpuhp_setup_state_nocalls_cpuslocked(CPUHP_KVM_PPC_BOOK3S_PREPARE,
+ "ppc/kvm_book3s:prepare",
+ kvmppc_set_host_core,
+ kvmppc_clear_host_core);
put_online_cpus();
}