If hardware errors are encountered during page copying, returning the bytes
not copied is not meaningful, and the caller cannot do any processing on
the remaining data. Returning -EFAULT is more reasonable, which represents
a hardware error encountered during the copying.
Signed-off-by: Tong Tiangen <tongtiangen@xxxxxxxxxx>
---
include/linux/highmem.h | 8 ++++----
mm/khugepaged.c | 4 ++--
2 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index 451c1dff0e87..c5ca1a1fc4f5 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -335,8 +335,8 @@ static inline void copy_highpage(struct page *to, struct page *from)
/*
* If architecture supports machine check exception handling, define the
* #MC versions of copy_user_highpage and copy_highpage. They copy a memory
- * page with #MC in source page (@from) handled, and return the number
- * of bytes not copied if there was a #MC, otherwise 0 for success.
+ * page with #MC in source page (@from) handled, and return -EFAULT if there
+ * was a #MC, otherwise 0 for success.
*/
static inline int copy_mc_user_highpage(struct page *to, struct page *from,
unsigned long vaddr, struct vm_area_struct *vma)
@@ -352,7 +352,7 @@ static inline int copy_mc_user_highpage(struct page *to, struct page *from,
kunmap_local(vto);
kunmap_local(vfrom);
- return ret;
+ return ret ? -EFAULT : 0;
}
static inline int copy_mc_highpage(struct page *to, struct page *from)
@@ -368,7 +368,7 @@ static inline int copy_mc_highpage(struct page *to, struct page *from)
kunmap_local(vto);
kunmap_local(vfrom);
- return ret;
+ return ret ? -EFAULT : 0;
}
#else
static inline int copy_mc_user_highpage(struct page *to, struct page *from,
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 2b219acb528e..ba6743a54c86 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -797,7 +797,7 @@ static int __collapse_huge_page_copy(pte_t *pte,
continue;
}
src_page = pte_page(pteval);
- if (copy_mc_user_highpage(page, src_page, _address, vma) > 0) {
+ if (copy_mc_user_highpage(page, src_page, _address, vma)) {
result = SCAN_COPY_MC;
break;
}
@@ -2053,7 +2053,7 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr,
clear_highpage(hpage + (index % HPAGE_PMD_NR));
index++;
}
- if (copy_mc_highpage(hpage + (page->index % HPAGE_PMD_NR), page) > 0) {
+ if (copy_mc_highpage(hpage + (page->index % HPAGE_PMD_NR), page)) {
result = SCAN_COPY_MC;
goto rollback;
}
--
2.25.1
