Merge "mm: remove gup_flags FOLL_WRITE games from __get_user_pages()" (35640cdd) · Commits · e / devices / android_kernel_sony_msm8998

include/linux/mm.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -2128,6 +2128,7 @@ static inline struct page follow_page(struct vm_area_struct vma,
		#define FOLL_MIGRATION 0x400 /* wait for page to replace migration entry */
		#define FOLL_TRIED 0x800 /* a retry, previous pass started an IO */
		#define FOLL_MLOCK 0x1000 /* lock present pages */
		#define FOLL_COW 0x4000 /* internal GUP flag */

		typedef int (pte_fn_t)(pte_t pte, pgtable_t token, unsigned long addr,
		void *data);

+12 −2

Original line number	Diff line number	Diff line
		@@ -58,6 +58,16 @@ static int follow_pfn_pte(struct vm_area_struct *vma, unsigned long address,
		return -EEXIST;
		}

		/*
		* FOLL_FORCE can write to even unwritable pte's, but only
		* after we've gone through a COW cycle and they are dirty.
		*/
		static inline bool can_follow_write_pte(pte_t pte, unsigned int flags)
		{
		return pte_write(pte) \|\|
		((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_dirty(pte));
		}

		static struct page follow_page_pte(struct vm_area_struct vma,
		unsigned long address, pmd_t *pmd, unsigned int flags)
		{
		@@ -92,7 +102,7 @@ retry:
		}
		if ((flags & FOLL_NUMA) && pte_protnone(pte))
		goto no_page;
		if ((flags & FOLL_WRITE) && !pte_write(pte)) {
		if ((flags & FOLL_WRITE) && !can_follow_write_pte(pte, flags)) {
		pte_unmap_unlock(ptep, ptl);
		return NULL;
		}
		@@ -352,7 +362,7 @@ static int faultin_page(struct task_struct tsk, struct vm_area_struct vma,
		* reCOWed by userspace write).
		*/
		if ((ret & VM_FAULT_WRITE) && !(vma->vm_flags & VM_WRITE))
		*flags &= ~FOLL_WRITE;
		*flags \|= FOLL_COW;
		return 0;
		}