linux-kernel - [PATCH 07/12] KVM: X86/MMU: Remove the useless struct mmu_page

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Date:   Sun,  5 Jun 2022 14:43:37 +0800
From:   Lai Jiangshan <jiangshanlai@...il.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Maxim Levitsky <mlevitsk@...hat.com>,
        Lai Jiangshan <jiangshan.ljs@...group.com>
Subject: [PATCH 07/12] KVM: X86/MMU: Remove the useless struct mmu_page_path

From: Lai Jiangshan <jiangshan.ljs@...group.com>

struct mmu_page_path is set and updated but never used since
mmu_pages_clear_parents() is removed.

Remove it.

Signed-off-by: Lai Jiangshan <jiangshan.ljs@...group.com>
---
 arch/x86/kvm/mmu/mmu.c | 37 +++++++++----------------------------
 1 file changed, 9 insertions(+), 28 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index a56d328365e4..65a2f4a2ce25 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1897,39 +1897,28 @@ static bool is_obsolete_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
 	       unlikely(sp->mmu_valid_gen != kvm->arch.mmu_valid_gen);
 }
 
-struct mmu_page_path {
-	struct kvm_mmu_page *parent[PT64_ROOT_MAX_LEVEL];
-	unsigned int idx[PT64_ROOT_MAX_LEVEL];
-};
-
-#define for_each_sp(pvec, sp, parents, i)			\
-		for (i = mmu_pages_first(&pvec, &parents);	\
+#define for_each_sp(pvec, sp, i)					\
+		for (i = mmu_pages_first(&pvec);			\
 			i < pvec.nr && ({ sp = pvec.page[i].sp; 1;});	\
-			i = mmu_pages_next(&pvec, &parents, i))
+			i = mmu_pages_next(&pvec, i))
 
-static int mmu_pages_next(struct kvm_mmu_pages *pvec,
-			  struct mmu_page_path *parents,
-			  int i)
+static int mmu_pages_next(struct kvm_mmu_pages *pvec, int i)
 {
 	int n;
 
 	for (n = i+1; n < pvec->nr; n++) {
 		struct kvm_mmu_page *sp = pvec->page[n].sp;
-		unsigned idx = pvec->page[n].idx;
 		int level = sp->role.level;
 
-		parents->idx[level-1] = idx;
 		if (level == PG_LEVEL_4K)
 			break;
 
-		parents->parent[level-2] = sp;
 	}
 
 	return n;
 }
 
-static int mmu_pages_first(struct kvm_mmu_pages *pvec,
-			   struct mmu_page_path *parents)
+static int mmu_pages_first(struct kvm_mmu_pages *pvec)
 {
 	struct kvm_mmu_page *sp;
 	int level;
@@ -1943,13 +1932,7 @@ static int mmu_pages_first(struct kvm_mmu_pages *pvec,
 	level = sp->role.level;
 	WARN_ON(level == PG_LEVEL_4K);
 
-	parents->parent[level-2] = sp;
-
-	/* Also set up a sentinel.  Further entries in pvec are all
-	 * children of sp, so this element is never overwritten.
-	 */
-	parents->parent[level-1] = NULL;
-	return mmu_pages_next(pvec, parents, 0);
+	return mmu_pages_next(pvec, 0);
 }
 
 static int mmu_sync_children(struct kvm_vcpu *vcpu,
@@ -1957,7 +1940,6 @@ static int mmu_sync_children(struct kvm_vcpu *vcpu,
 {
 	int i;
 	struct kvm_mmu_page *sp;
-	struct mmu_page_path parents;
 	struct kvm_mmu_pages pages;
 	LIST_HEAD(invalid_list);
 	bool flush = false;
@@ -1965,7 +1947,7 @@ static int mmu_sync_children(struct kvm_vcpu *vcpu,
 	while (mmu_unsync_walk_and_clear(parent, &pages)) {
 		bool protected = false;
 
-		for_each_sp(pages, sp, parents, i)
+		for_each_sp(pages, sp, i)
 			protected |= kvm_vcpu_write_protect_gfn(vcpu, sp->gfn);
 
 		if (protected) {
@@ -1973,7 +1955,7 @@ static int mmu_sync_children(struct kvm_vcpu *vcpu,
 			flush = false;
 		}
 
-		for_each_sp(pages, sp, parents, i) {
+		for_each_sp(pages, sp, i) {
 			kvm_mmu_page_clear_unsync(vcpu->kvm, sp);
 			flush |= kvm_sync_page(vcpu, sp, &invalid_list) > 0;
 		}
@@ -2273,7 +2255,6 @@ static int mmu_zap_unsync_children(struct kvm *kvm,
 				   struct list_head *invalid_list)
 {
 	int i, zapped = 0;
-	struct mmu_page_path parents;
 	struct kvm_mmu_pages pages;
 
 	if (parent->role.level == PG_LEVEL_4K)
@@ -2282,7 +2263,7 @@ static int mmu_zap_unsync_children(struct kvm *kvm,
 	while (mmu_unsync_walk_and_clear(parent, &pages)) {
 		struct kvm_mmu_page *sp;
 
-		for_each_sp(pages, sp, parents, i) {
+		for_each_sp(pages, sp, i) {
 			kvm_mmu_prepare_zap_page(kvm, sp, invalid_list);
 			zapped++;
 		}
-- 
2.19.1.6.gb485710b