Commit ad6e519b authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds

[PATCH] mm: follow_page invalid pte_page

The follow_page write-access case is relying on pte_page before checking
pfn_valid: rearrange that - and we don't need three struct page *pages.

(I notice mempolicy.c's verify_pages is also relying on pte_page, but I'll
leave that to Andi: maybe it ought to be failing on, or skipping over, VM_IO
or VM_RESERVED vmas?)
Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent e11f2cc4
......@@ -637,15 +637,11 @@ follow_page(struct mm_struct *mm, unsigned long address, int write)
if (pte_present(pte)) {
if (write && !pte_write(pte))
goto out;
if (write && !pte_dirty(pte)) {
struct page *page = pte_page(pte);
if (!PageDirty(page))
set_page_dirty(page);
}
pfn = pte_pfn(pte);
if (pfn_valid(pfn)) {
struct page *page = pfn_to_page(pfn);
page = pfn_to_page(pfn);
if (write && !pte_dirty(pte) && !PageDirty(page))
set_page_dirty(page);
mark_page_accessed(page);
return page;
}
......
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