1 files changed, 105 insertions, 8 deletions

diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c
index e1d85137f086..10ea71905c1f 100644
--- a/mm/hwpoison-inject.c
+++ b/mm/hwpoison-inject.c
@@ -3,18 +3,68 @@
 #include <linux/debugfs.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/pagemap.h>
+#include "internal.h"
 
-static struct dentry *hwpoison_dir, *corrupt_pfn;
+static struct dentry *hwpoison_dir;
 
 static int hwpoison_inject(void *data, u64 val)
 {
+        unsigned long pfn = val;
+        struct page *p;
+        int err;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+
+        if (!hwpoison_filter_enable)
+                goto inject;
+        if (!pfn_valid(pfn))
+                return -ENXIO;
+
+        p = pfn_to_page(pfn);
+        /*
+         * This implies unable to support free buddy pages.
+         */
+        if (!get_page_unless_zero(p))
+                return 0;
+
+        if (!PageLRU(p))
+                shake_page(p, 0);
+        /*
+         * This implies unable to support non-LRU pages.
+         */
+        if (!PageLRU(p))
+                return 0;
+
+        /*
+         * do a racy check with elevated page count, to make sure PG_hwpoison
+         * will only be set for the targeted owner (or on a free page).
+         * We temporarily take page lock for try_get_mem_cgroup_from_page().
+         * __memory_failure() will redo the check reliably inside page lock.
+         */
+        lock_page(p);
+        err = hwpoison_filter(p);
+        unlock_page(p);
+        if (err)
+                return 0;
+
+inject:
+        printk(KERN_INFO "Injecting memory failure at pfn %lx\n", pfn);
+        return __memory_failure(pfn, 18, MF_COUNT_INCREASED);
+}
+
+static int hwpoison_unpoison(void *data, u64 val)
+{
         if (!capable(CAP_SYS_ADMIN))
                 return -EPERM;
-        printk(KERN_INFO "Injecting memory failure at pfn %Lx\n", val);
-        return __memory_failure(val, 18, 0);
+
+        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 +74,63 @@ 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;
+
+        dentry = debugfs_create_u32("corrupt-filter-enable", 0600,
+                                    hwpoison_dir, &hwpoison_filter_enable);
+        if (!dentry)
+                goto fail;
+
+        dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600,
+                                    hwpoison_dir, &hwpoison_filter_dev_major);
+        if (!dentry)
+                goto fail;
+
+        dentry = debugfs_create_u32("corrupt-filter-dev-minor", 0600,
+                                    hwpoison_dir, &hwpoison_filter_dev_minor);
+        if (!dentry)
+                goto fail;
+
+        dentry = debugfs_create_u64("corrupt-filter-flags-mask", 0600,
+                                    hwpoison_dir, &hwpoison_filter_flags_mask);
+        if (!dentry)
+                goto fail;
+
+        dentry = debugfs_create_u64("corrupt-filter-flags-value", 0600,
+                                    hwpoison_dir, &hwpoison_filter_flags_value);
+        if (!dentry)
+                goto fail;
+
+#ifdef  CONFIG_CGROUP_MEM_RES_CTLR_SWAP
+        dentry = debugfs_create_u64("corrupt-filter-memcg", 0600,
+                                    hwpoison_dir, &hwpoison_filter_memcg);
+        if (!dentry)
+                goto fail;
+#endif
+
         return 0;
+fail:
+        pfn_inject_exit();
+        return -ENOMEM;
 }
 
 module_init(pfn_inject_init);