!1251 [sync] PR-1191: fix memory reliable related issues

Merge Pull Request from: @openeuler-sync-bot 
 

Origin pull request: 
https://gitee.com/openeuler/kernel/pulls/1191 
 
PR sync from: Wupeng Ma <mawupeng1@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/DBYQ7YX2NZXNZFVXLHOUZRNTPCMRY75Q/ 
From: Ma Wupeng <mawupeng1@huawei.com>

Fix memory reliable related issues.

Ma Wupeng (3):
  mm: mem_reliable: Fix reliable page counter mismatch problem
  mm: mem_reliable: Update reliable page counter to zero if underflows
  efi: Disable mirror feature during crashkernel


-- 
2.25.1
 
 
Link:https://gitee.com/openeuler/kernel/pulls/1251 

Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> 
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com> 

drivers/firmware/efi/efi.c

@@ -31,6 +31,7 @@
 #include <linux/ucs2_string.h>
 #include <linux/memblock.h>
 #include <linux/security.h>
+#include <linux/crash_dump.h>
 
 #include <asm/early_ioremap.h>
 
@@ -446,6 +447,11 @@ void __init efi_find_mirror(void)
 	if (!mirrored_kernelcore)
 		return;
 
+	if (is_kdump_kernel()) {
+		mirrored_kernelcore = false;
+		return;
+	}
+
 	for_each_efi_memory_desc(md) {
 		unsigned long long start = md->phys_addr;
 		unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;

include/linux/mem_reliable.h

@@ -132,8 +132,19 @@ static inline bool reliable_allow_fb_enabled(void)
 static inline void reliable_page_counter(struct page *page,
 		struct mm_struct *mm, int val)
 {
-	if (page_reliable(page))
-		atomic_long_add(val, &mm->reliable_nr_page);
+	if (!page_reliable(page))
+		return;
+
+	atomic_long_add(val, &mm->reliable_nr_page);
+
+	/*
+	 * Update reliable page counter to zero if underflows.
+	 *
+	 * Since reliable page counter is used for debug purpose only,
+	 * there is no real function problem by doing this.
+	 */
+	if (unlikely(atomic_long_read(&mm->reliable_nr_page) < 0))
+		atomic_long_set(&mm->reliable_nr_page, 0);
 }
 
 static inline void reliable_clear_page_counter(struct mm_struct *mm)

mm/memory.c

@@ -886,6 +886,7 @@ copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
 		get_page(page);
 		page_dup_rmap(page, false);
 		rss[mm_counter(page)]++;
+		reliable_page_counter(page, dst_vma->vm_mm, 1);
 	}
 
 	/*