commit c6170b81e7b78942cb4b36fc72cbd75145fd08d5
author Junaid Shahid <junaids@google.com> Thu Jan 03 17:14:28 2019 -0800
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> Sat Nov 16 10:29:49 2019 +0100
tree e45a4c8fb8dc8357dc6ee8d5995d7f8de71fd10e
parent 61524f1bccc041b7871a21984b69b8e538f446c0

kvm: Convert kvm_lock to a mutex

commit 0d9ce162cf46c99628cc5da9510b959c7976735b upstream.

It doesn't seem as if there is any particular need for kvm_lock to be a
spinlock, so convert the lock to a mutex so that sleepable functions (in
particular cond_resched()) can be called while holding it.

Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[bwh: Backported to 4.9:
 - Drop changes in kvm_hyperv_tsc_notifier(), vm_stat_clear(),
   vcpu_stat_clear(), kvm_uevent_notify_change()
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

virt/kvm/kvm_main.c

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c72586a..7af67b2 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -87,7 +87,7 @@
  *	kvm->lock --> kvm->slots_lock --> kvm->irq_lock
  */
 
-DEFINE_SPINLOCK(kvm_lock);
+DEFINE_MUTEX(kvm_lock);
 static DEFINE_RAW_SPINLOCK(kvm_count_lock);
 LIST_HEAD(vm_list);
 
@@ -666,9 +666,9 @@
 	if (r)
 		goto out_err;
 
-	spin_lock(&kvm_lock);
+	mutex_lock(&kvm_lock);
 	list_add(&kvm->vm_list, &vm_list);
-	spin_unlock(&kvm_lock);
+	mutex_unlock(&kvm_lock);
 
 	preempt_notifier_inc();
 
@@ -724,9 +724,9 @@
 
 	kvm_destroy_vm_debugfs(kvm);
 	kvm_arch_sync_events(kvm);
-	spin_lock(&kvm_lock);
+	mutex_lock(&kvm_lock);
 	list_del(&kvm->vm_list);
-	spin_unlock(&kvm_lock);
+	mutex_unlock(&kvm_lock);
 	kvm_free_irq_routing(kvm);
 	for (i = 0; i < KVM_NR_BUSES; i++) {
 		if (kvm->buses[i])
@@ -3752,13 +3752,13 @@
 	u64 tmp_val;
 
 	*val = 0;
-	spin_lock(&kvm_lock);
+	mutex_lock(&kvm_lock);
 	list_for_each_entry(kvm, &vm_list, vm_list) {
 		stat_tmp.kvm = kvm;
 		vm_stat_get_per_vm((void *)&stat_tmp, &tmp_val);
 		*val += tmp_val;
 	}
-	spin_unlock(&kvm_lock);
+	mutex_unlock(&kvm_lock);
 	return 0;
 }
 
@@ -3772,13 +3772,13 @@
 	u64 tmp_val;
 
 	*val = 0;
-	spin_lock(&kvm_lock);
+	mutex_lock(&kvm_lock);
 	list_for_each_entry(kvm, &vm_list, vm_list) {
 		stat_tmp.kvm = kvm;
 		vcpu_stat_get_per_vm((void *)&stat_tmp, &tmp_val);
 		*val += tmp_val;
 	}
-	spin_unlock(&kvm_lock);
+	mutex_unlock(&kvm_lock);
 	return 0;
 }