From: Marcelo Tosatti <mtosatti@redhat.com>
Date: Tue, 8 Sep 2009 17:47:38 +0000 (-0300)
Subject: KVM: SVM: remove needless mmap_sem acquision from nested_svm_map
X-Git-Tag: v2.6.33-rc1~387^2~61
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=e8b3433a5c062e94e34cadb6144c10689a497bc3;p=linux-2.6-block.git

KVM: SVM: remove needless mmap_sem acquision from nested_svm_map

nested_svm_map unnecessarily takes mmap_sem around gfn_to_page, since
gfn_to_page / get_user_pages are responsible for it.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Acked-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
---

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 92048a626d4e..f54c4f9d2865 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1396,10 +1396,7 @@ static void *nested_svm_map(struct vcpu_svm *svm, u64 gpa, enum km_type idx)
 {
 	struct page *page;
 
-	down_read(&current->mm->mmap_sem);
 	page = gfn_to_page(svm->vcpu.kvm, gpa >> PAGE_SHIFT);
-	up_read(&current->mm->mmap_sem);
-
 	if (is_error_page(page))
 		goto error;