Commit 58fa879e authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
Browse files

mm: FOLL flags for GUP flags 



__get_user_pages() has been taking its own GUP flags, then processing
them into FOLL flags for follow_page().  Though oddly named, the FOLL
flags are more widely used, so pass them to __get_user_pages() now.
Sorry, VM flags, VM_FAULT flags and FAULT_FLAGs are still distinct.

(The patch to __get_user_pages() looks peculiar, with both gup_flags
and foll_flags: the gup_flags remain constant; but as before there's
an exceptional case, out of scope of the patch, in which foll_flags
per page have FOLL_WRITE masked off.)

Signed-off-by: default avatarHugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a13ea5b7

include/linux/mm.h

+1 −0
Original line number Diff line number Diff line
@@ -1232,6 +1232,7 @@ struct page *follow_page(struct vm_area_struct *, unsigned long address, 
#define FOLL_TOUCH	0x02	/* mark page accessed */

#define FOLL_GET	0x04	/* do get_page on page */

#define FOLL_DUMP	0x08	/* give error on hole if it would be zero */

#define FOLL_FORCE	0x10	/* get_user_pages read/write w/o permission */



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

			void *data);

mm/internal.h

+1 −5
Original line number Diff line number Diff line
@@ -250,12 +250,8 @@ static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn, 
}

#endif /* CONFIG_SPARSEMEM */



#define GUP_FLAGS_WRITE		0x01

#define GUP_FLAGS_FORCE		0x02

#define GUP_FLAGS_DUMP		0x04



int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,

		     unsigned long start, int len, int flags,

		     unsigned long start, int len, unsigned int foll_flags,

		     struct page **pages, struct vm_area_struct **vmas);



#define ZONE_RECLAIM_NOSCAN	-2

mm/memory.c

+19 −25
Original line number Diff line number Diff line
@@ -1209,27 +1209,29 @@ no_page_table: 
}



int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,

		     unsigned long start, int nr_pages, int flags,

		     unsigned long start, int nr_pages, unsigned int gup_flags,

		     struct page **pages, struct vm_area_struct **vmas)

{

	int i;

	unsigned int vm_flags = 0;

	int write = !!(flags & GUP_FLAGS_WRITE);

	int force = !!(flags & GUP_FLAGS_FORCE);

	unsigned long vm_flags;



	if (nr_pages <= 0)

		return 0;



	VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));



	/* 

	 * Require read or write permissions.

	 * If 'force' is set, we only require the "MAY" flags.

	 * If FOLL_FORCE is set, we only require the "MAY" flags.

	 */

	vm_flags  = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);

	vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);

	vm_flags  = (gup_flags & FOLL_WRITE) ?

			(VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);

	vm_flags &= (gup_flags & FOLL_FORCE) ?

			(VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);

	i = 0;



	do {

		struct vm_area_struct *vma;

		unsigned int foll_flags;



		vma = find_extend_vma(mm, start);

		if (!vma && in_gate_area(tsk, start)) {
@@ -1241,7 +1243,7 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, 
			pte_t *pte;



			/* user gate pages are read-only */

			if (write)

			if (gup_flags & FOLL_WRITE)

				return i ? : -EFAULT;

			if (pg > TASK_SIZE)

				pgd = pgd_offset_k(pg);
@@ -1278,22 +1280,15 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, 
		    !(vm_flags & vma->vm_flags))

			return i ? : -EFAULT;



		foll_flags = FOLL_TOUCH;

		if (pages)

			foll_flags |= FOLL_GET;

		if (flags & GUP_FLAGS_DUMP)

			foll_flags |= FOLL_DUMP;

		if (write)

			foll_flags |= FOLL_WRITE;



		if (is_vm_hugetlb_page(vma)) {

			i = follow_hugetlb_page(mm, vma, pages, vmas,

					&start, &nr_pages, i, foll_flags);

					&start, &nr_pages, i, gup_flags);

			continue;

		}



		do {

			struct page *page;

			unsigned int foll_flags = gup_flags;



			/*

			 * If we have a pending SIGKILL, don't keep faulting
@@ -1302,9 +1297,6 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, 
			if (unlikely(fatal_signal_pending(current)))

				return i ? i : -ERESTARTSYS;



			if (write)

				foll_flags |= FOLL_WRITE;



			cond_resched();

			while (!(page = follow_page(vma, start, foll_flags))) {

				int ret;
@@ -1415,12 +1407,14 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, 
		unsigned long start, int nr_pages, int write, int force,

		struct page **pages, struct vm_area_struct **vmas)

{

	int flags = 0;

	int flags = FOLL_TOUCH;



	if (pages)

		flags |= FOLL_GET;

	if (write)

		flags |= GUP_FLAGS_WRITE;

		flags |= FOLL_WRITE;

	if (force)

		flags |= GUP_FLAGS_FORCE;

		flags |= FOLL_FORCE;



	return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);

}
@@ -1447,7 +1441,7 @@ struct page *get_dump_page(unsigned long addr) 
	struct page *page;



	if (__get_user_pages(current, current->mm, addr, 1,

			GUP_FLAGS_FORCE | GUP_FLAGS_DUMP, &page, &vma) < 1)

			FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma) < 1)

		return NULL;

	if (page == ZERO_PAGE(0)) {

		page_cache_release(page);

mm/mlock.c

+2 −2
Original line number Diff line number Diff line
@@ -166,9 +166,9 @@ static long __mlock_vma_pages_range(struct vm_area_struct *vma, 
	VM_BUG_ON(end   > vma->vm_end);

	VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem));



	gup_flags = 0;

	gup_flags = FOLL_TOUCH | FOLL_GET;

	if (vma->vm_flags & VM_WRITE)

		gup_flags = GUP_FLAGS_WRITE;

		gup_flags |= FOLL_WRITE;



	while (nr_pages > 0) {

		int i;

mm/nommu.c

+8 −8
Original line number Diff line number Diff line
@@ -168,20 +168,20 @@ unsigned int kobjsize(const void *objp) 
}



int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,

		     unsigned long start, int nr_pages, int flags,

		     unsigned long start, int nr_pages, int foll_flags,

		     struct page **pages, struct vm_area_struct **vmas)

{

	struct vm_area_struct *vma;

	unsigned long vm_flags;

	int i;

	int write = !!(flags & GUP_FLAGS_WRITE);

	int force = !!(flags & GUP_FLAGS_FORCE);



	/* calculate required read or write permissions.

	 * - if 'force' is set, we only require the "MAY" flags.

	 * If FOLL_FORCE is set, we only require the "MAY" flags.

	 */

	vm_flags  = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);

	vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);

	vm_flags  = (foll_flags & FOLL_WRITE) ?

			(VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);

	vm_flags &= (foll_flags & FOLL_FORCE) ?

			(VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);



	for (i = 0; i < nr_pages; i++) {

		vma = find_vma(mm, start);
@@ -223,9 +223,9 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, 
	int flags = 0;



	if (write)

		flags |= GUP_FLAGS_WRITE;

		flags |= FOLL_WRITE;

	if (force)

		flags |= GUP_FLAGS_FORCE;

		flags |= FOLL_FORCE;



	return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);

}

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