linux-kernel - [PATCH] Revert "KVM: Eliminate extra function calls in kvm_get_dirty_log

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Date:   Sat,  2 Feb 2019 17:20:27 +0800
From:   lantianyu1986@...il.com
To:     unlisted-recipients:; (no To-header on input)
Cc:     Lan Tianyu <Tianyu.Lan@...rosoft.com>, pbonzini@...hat.com,
        rkrcmar@...hat.com, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, sean.j.christopherson@...el.com
Subject: [PATCH] Revert "KVM: Eliminate extra function calls in kvm_get_dirty_log_protect()"

From: Lan Tianyu <Tianyu.Lan@...rosoft.com>

The value of "dirty_bitmap[i]" is already check before setting its value
to mask. The following check of "mask" is redundant. The check of "mask" was
introduced by commit 58d2930f4ee3(("KVM: Eliminate extra function calls in
kvm_get_dirty_log_protect()"). This patch is to revert the patch.

Signed-off-by: Lan Tianyu <Tianyu.Lan@...rosoft.com>
---
 virt/kvm/kvm_main.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 2bdc827b9ee9..ef06cfb9b52b 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1200,11 +1200,9 @@ int kvm_get_dirty_log_protect(struct kvm *kvm,
 			mask = xchg(&dirty_bitmap[i], 0);
 			dirty_bitmap_buffer[i] = mask;
 
-			if (mask) {
-				offset = i * BITS_PER_LONG;
-				kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot,
-									offset, mask);
-			}
+			offset = i * BITS_PER_LONG;
+			kvm_arch_mmu_enable_log_dirty_pt_masked(kvm, memslot,
+								offset, mask);
 		}
 		spin_unlock(&kvm->mmu_lock);
 	}
-- 
2.14.4