1 files changed, 30 insertions, 6 deletions

diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c
index e1d85137f086..6e35e563bf50 100644
--- a/mm/hwpoison-inject.c
+++ b/mm/hwpoison-inject.c
@@ -4,7 +4,7 @@
 #include <linux/kernel.h>
 #include <linux/mm.h>
 
-static struct dentry *hwpoison_dir, *corrupt_pfn;
+static struct dentry *hwpoison_dir;
 
 static int hwpoison_inject(void *data, u64 val)
 {
@@ -14,7 +14,16 @@ static int hwpoison_inject(void *data, u64 val)
         return __memory_failure(val, 18, 0);
 }
 
+static int hwpoison_unpoison(void *data, u64 val)
+{
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+
+        return unpoison_memory(val);
+}
+
 DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
+DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
 
 static void pfn_inject_exit(void)
 {
@@ -24,16 +33,31 @@ static void pfn_inject_exit(void)
 
 static int pfn_inject_init(void)
 {
+        struct dentry *dentry;
+
         hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
         if (hwpoison_dir == NULL)
                 return -ENOMEM;
-        corrupt_pfn = debugfs_create_file("corrupt-pfn", 0600, hwpoison_dir,
+
+        /*
+         * Note that the below poison/unpoison interfaces do not involve
+         * hardware status change, hence do not require hardware support.
+         * They are mainly for testing hwpoison in software level.
+         */
+        dentry = debugfs_create_file("corrupt-pfn", 0600, hwpoison_dir,
                                           NULL, &hwpoison_fops);
-        if (corrupt_pfn == NULL) {
-                pfn_inject_exit();
-                return -ENOMEM;
-        }
+        if (!dentry)
+                goto fail;
+
+        dentry = debugfs_create_file("unpoison-pfn", 0600, hwpoison_dir,
+                                     NULL, &unpoison_fops);
+        if (!dentry)
+                goto fail;
+
         return 0;
+fail:
+        pfn_inject_exit();
+        return -ENOMEM;
 }
 
 module_init(pfn_inject_init);