KVM: x86: MMU: Add helper function to clear a bit in unsync child bitmap

Both __mmu_unsync_walk() and mmu_pages_clear_parents() have three line
code which clears a bit in the unsync child bitmap; the former places it
inside a loop block and uses a few goto statements to jump to it.

A new helper function, clear_unsync_child_bit(), makes the code cleaner.

Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 18 insertions, 18 deletions

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 8a1593f985df..9832bc9e937e 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1809,6 +1809,13 @@ static int mmu_pages_add(struct kvm_mmu_pages *pvec, struct kvm_mmu_page *sp,
         return (pvec->nr == KVM_PAGE_ARRAY_NR);
 }
 
+static inline void clear_unsync_child_bit(struct kvm_mmu_page *sp, int idx)
+{
+        --sp->unsync_children;
+        WARN_ON((int)sp->unsync_children < 0);
+        __clear_bit(idx, sp->unsync_child_bitmap);
+}
+
 static int __mmu_unsync_walk(struct kvm_mmu_page *sp,
                            struct kvm_mmu_pages *pvec)
 {
@@ -1818,8 +1825,10 @@ static int __mmu_unsync_walk(struct kvm_mmu_page *sp,
                 struct kvm_mmu_page *child;
                 u64 ent = sp->spt[i];
 
-                if (!is_shadow_present_pte(ent) || is_large_pte(ent))
-                        goto clear_child_bitmap;
+                if (!is_shadow_present_pte(ent) || is_large_pte(ent)) {
+                        clear_unsync_child_bit(sp, i);
+                        continue;
+                }
 
                 child = page_header(ent & PT64_BASE_ADDR_MASK);
 
@@ -1828,28 +1837,21 @@ static int __mmu_unsync_walk(struct kvm_mmu_page *sp,
                                 return -ENOSPC;
 
                         ret = __mmu_unsync_walk(child, pvec);
-                        if (!ret)
-                                goto clear_child_bitmap;
-                        else if (ret > 0)
+                        if (!ret) {
+                                clear_unsync_child_bit(sp, i);
+                                continue;
+                        } else if (ret > 0) {
                                 nr_unsync_leaf += ret;
-                        else
+                        } else
                                 return ret;
                 } else if (child->unsync) {
                         nr_unsync_leaf++;
                         if (mmu_pages_add(pvec, child, i))
                                 return -ENOSPC;
                 } else
-                         goto clear_child_bitmap;
-
-                continue;
-
-clear_child_bitmap:
-                __clear_bit(i, sp->unsync_child_bitmap);
-                sp->unsync_children--;
-                WARN_ON((int)sp->unsync_children < 0);
+                        clear_unsync_child_bit(sp, i);
         }
 
-
         return nr_unsync_leaf;
 }
 
@@ -2012,9 +2014,7 @@ static void mmu_pages_clear_parents(struct mmu_page_path *parents)
                 if (!sp)
                         return;
 
-                --sp->unsync_children;
-                WARN_ON((int)sp->unsync_children < 0);
-                __clear_bit(idx, sp->unsync_child_bitmap);
+                clear_unsync_child_bit(sp, idx);
                 level++;
         } while (level < PT64_ROOT_LEVEL-1 && !sp->unsync_children);
 }