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Commit 7b3b9aa4 authored by Omkar Savagaonkar's avatar Omkar Savagaonkar Committed by Gerrit - the friendly Code Review server
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Hibernate: Add check for pte_valid in saveable page 



Add check for pte_valid in saveable page after being checked for
the rest. This is required as PTE is removed for pages allocated
with __dma_alloc_coherent with DMA_ATTR_NO_KERNEL_MAPPING flag set.
This patch makes sure that these pages are not considered for
snapshot.

Change-Id: Idc7dede2d45be0a8e19899004b5277e5aba24db8
Signed-off-by: default avatarOmkar Savagaonkar <omkars@codeaurora.org>
parent 13a99086

kernel/power/snapshot.c

+35 −0
Original line number Diff line number Diff line
@@ -1257,6 +1257,33 @@ static inline void *saveable_highmem_page(struct zone *z, unsigned long p) 
}

#endif /* CONFIG_HIGHMEM */



static bool kernel_pte_present(struct page *page)

{

	pgd_t *pgd;

	pud_t *pud;

	pmd_t *pmd;

	pte_t *pte;

	unsigned long addr = (unsigned long)page_address(page);



	pgd = pgd_offset_k(addr);

	if (pgd_none(*pgd))

		return false;



	pud = pud_offset(pgd, addr);

	if (pud_none(*pud))

		return false;

	if (pud_sect(*pud))

		return true;



	pmd = pmd_offset(pud, addr);

	if (pmd_none(*pmd))

		return false;

	if (pmd_sect(*pmd))

		return true;



	pte = pte_offset_kernel(pmd, addr);

	return pte_valid(*pte);

}

/**

 * saveable_page - Check if the given page is saveable.

 *
@@ -1287,6 +1314,14 @@ static struct page *saveable_page(struct zone *zone, unsigned long pfn) 
	    && (!kernel_page_present(page) || pfn_is_nosave(pfn)))

		return NULL;



	/*

	 * Even if page is not reserved and if it's not present in kernel PTE;

	 * don't snapshot it ! This happens to the pages allocated using

	 * __dma_alloc_coherent with DMA_ATTR_NO_KERNEL_MAPPING flag set.

	 */

	if (!kernel_pte_present(page))

		return NULL;



	if (page_is_guard(page))

		return NULL;