On 1/19/23 10:00 PM, Matthew Wilcox wrote:
On Thu, Jan 19, 2023 at 01:14:41PM -0800, Sidhartha Kumar wrote:
@@ -5599,9 +5603,9 @@ static vm_fault_t hugetlb_wp(struct mm_struct *mm, struct vm_area_struct *vma,
goto out_release_all;
}
- copy_user_huge_page(new_page, old_page, address, vma,
+ copy_user_huge_page(&new_folio->page, old_page, address, vma,
pages_per_huge_page(h));
We have a folio_copy(), but it feels to me like we need a
folio_copy_user() so that we can use copy_user_page() on machines
with virtual caches.
@@ -6176,6 +6186,7 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
spinlock_t *ptl;
int ret = -ENOMEM;
struct page *page;
+ struct folio *folio = NULL;
int writable;
bool page_in_pagecache = false;
@@ -6251,12 +6262,15 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
*pagep = NULL;
}
+ if (page)
+ folio = page_folio(page);
+
/*
- * The memory barrier inside __SetPageUptodate makes sure that
+ * The memory barrier inside __folio_mark_uptodate makes sure that
* preceding stores to the page contents become visible before
* the set_pte_at() write.
*/
- __SetPageUptodate(page);
+ __folio_mark_uptodate(folio);
Hi Matthew,
In the snippet:
page = alloc_huge_page(dst_vma, dst_addr, 0);
if (IS_ERR(page)) {
put_page(*pagep);
ret = -ENOMEM;
*pagep = NULL;
goto out;
}
copy_user_huge_page(page, *pagep, dst_addr, dst_vma,
pages_per_huge_page(h));
I thought the IS_ERR() call does not handle the NULL case and is a check
for high memory addresses, and copy_user_huge_page() path does not seem
to handle the NULL case as well but alloc_huge_page() can possibly
return NULL so I was unsure about how to handle the folio conversion.
I suggest that "page" can never be NULL or __SetPageUptodate() would
have crashed.
