From cba8d9e6d80634b4b586b3f695d2054a25d69509 Mon Sep 17 00:00:00 2001
From: Yifan Wu <shinbokuow@163.com>
Date: Thu, 13 Jan 2022 17:27:09 -0800
Subject: [PATCH] Now PageTable::unmap calls PageTable::find_pte instead of
 PageTable::find_pte_create.

---
 os/src/mm/page_table.rs | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/os/src/mm/page_table.rs b/os/src/mm/page_table.rs
index d1bc645f..0ce485ce 100644
--- a/os/src/mm/page_table.rs
+++ b/os/src/mm/page_table.rs
@@ -102,12 +102,12 @@ impl PageTable {
         }
         result
     }
-    fn find_pte(&self, vpn: VirtPageNum) -> Option<&PageTableEntry> {
+    fn find_pte(&self, vpn: VirtPageNum) -> Option<&mut PageTableEntry> {
         let idxs = vpn.indexes();
         let mut ppn = self.root_ppn;
-        let mut result: Option<&PageTableEntry> = None;
+        let mut result: Option<&mut PageTableEntry> = None;
         for i in 0..3 {
-            let pte = &ppn.get_pte_array()[idxs[i]];
+            let pte = &mut ppn.get_pte_array()[idxs[i]];
             if i == 2 {
                 result = Some(pte);
                 break;
@@ -127,7 +127,7 @@ impl PageTable {
     }
     #[allow(unused)]
     pub fn unmap(&mut self, vpn: VirtPageNum) {
-        let pte = self.find_pte_create(vpn).unwrap();
+        let pte = self.find_pte(vpn).unwrap();
         assert!(pte.is_valid(), "vpn {:?} is invalid before unmapping", vpn);
         *pte = PageTableEntry::empty();
     }