[mirror_ubuntu-zesty-kernel.git] / mm / madvise.c

/*
 *	linux/mm/madvise.c
 *
 * Copyright (C) 1999  Linus Torvalds
 * Copyright (C) 2002  Christoph Hellwig
 */

#include <linux/mman.h>
#include <linux/pagemap.h>
#include <linux/syscalls.h>
#include <linux/mempolicy.h>
#include <linux/hugetlb.h>
#include <linux/sched.h>

/*
 * Any behaviour which results in changes to the vma->vm_flags needs to
 * take mmap_sem for writing. Others, which simply traverse vmas, need
 * to only take it for reading.
 */
static int madvise_need_mmap_write(int behavior)
{
	switch (behavior) {
	case MADV_REMOVE:
	case MADV_WILLNEED:
	case MADV_DONTNEED:
		return 0;
	default:
		/* be safe, default to 1. list exceptions explicitly */
		return 1;
	}
}

/*
 * We can potentially split a vm area into separate
 * areas, each area with its own behavior.
 */
static long madvise_behavior(struct vm_area_struct * vma,
		     struct vm_area_struct **prev,
		     unsigned long start, unsigned long end, int behavior)
{
	struct mm_struct * mm = vma->vm_mm;
	int error = 0;
	pgoff_t pgoff;
	int new_flags = vma->vm_flags;

	switch (behavior) {
	case MADV_NORMAL:
		new_flags = new_flags & ~VM_RAND_READ & ~VM_SEQ_READ;
		break;
	case MADV_SEQUENTIAL:
		new_flags = (new_flags & ~VM_RAND_READ) | VM_SEQ_READ;
		break;
	case MADV_RANDOM:
		new_flags = (new_flags & ~VM_SEQ_READ) | VM_RAND_READ;
		break;
	case MADV_DONTFORK:
		new_flags |= VM_DONTCOPY;
		break;
	case MADV_DOFORK:
		new_flags &= ~VM_DONTCOPY;
		break;
	}

	if (new_flags == vma->vm_flags) {
		*prev = vma;
		goto out;
	}

	pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
	*prev = vma_merge(mm, *prev, start, end, new_flags, vma->anon_vma,
				vma->vm_file, pgoff, vma_policy(vma));
	if (*prev) {
		vma = *prev;
		goto success;
	}

	*prev = vma;

	if (start != vma->vm_start) {
		error = split_vma(mm, vma, start, 1);
		if (error)
			goto out;
	}

	if (end != vma->vm_end) {
		error = split_vma(mm, vma, end, 0);
		if (error)
			goto out;
	}

success:
	/*
	 * vm_flags is protected by the mmap_sem held in write mode.
	 */
	vma->vm_flags = new_flags;

out:
	if (error == -ENOMEM)
		error = -EAGAIN;
	return error;
}

/*
 * Schedule all required I/O operations.  Do not wait for completion.
 */
static long madvise_willneed(struct vm_area_struct * vma,
			     struct vm_area_struct ** prev,
			     unsigned long start, unsigned long end)
{
	struct file *file = vma->vm_file;

	if (!file)
		return -EBADF;

	if (file->f_mapping->a_ops->get_xip_page) {
		/* no bad return value, but ignore advice */
		return 0;
	}

	*prev = vma;
	start = ((start - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
	if (end > vma->vm_end)
		end = vma->vm_end;
	end = ((end - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;

	force_page_cache_readahead(file->f_mapping,
			file, start, max_sane_readahead(end - start));
	return 0;
}

/*
 * Application no longer needs these pages.  If the pages are dirty,
 * it's OK to just throw them away.  The app will be more careful about
 * data it wants to keep.  Be sure to free swap resources too.  The
 * zap_page_range call sets things up for refill_inactive to actually free
 * these pages later if no one else has touched them in the meantime,
 * although we could add these pages to a global reuse list for
 * refill_inactive to pick up before reclaiming other pages.
 *
 * NB: This interface discards data rather than pushes it out to swap,
 * as some implementations do.  This has performance implications for
 * applications like large transactional databases which want to discard
 * pages in anonymous maps after committing to backing store the data
 * that was kept in them.  There is no reason to write this data out to
 * the swap area if the application is discarding it.
 *
 * An interface that causes the system to free clean pages and flush
 * dirty pages is already available as msync(MS_INVALIDATE).
 */
static long madvise_dontneed(struct vm_area_struct * vma,
			     struct vm_area_struct ** prev,
			     unsigned long start, unsigned long end)
{
	*prev = vma;
	if (vma->vm_flags & (VM_LOCKED|VM_HUGETLB|VM_PFNMAP))
		return -EINVAL;

	if (unlikely(vma->vm_flags & VM_NONLINEAR)) {
		struct zap_details details = {
			.nonlinear_vma = vma,
			.last_index = ULONG_MAX,
		};
		zap_page_range(vma, start, end - start, &details);
	} else
		zap_page_range(vma, start, end - start, NULL);
	return 0;
}

/*
 * Application wants to free up the pages and associated backing store.
 * This is effectively punching a hole into the middle of a file.
 *
 * NOTE: Currently, only shmfs/tmpfs is supported for this operation.
 * Other filesystems return -ENOSYS.
 */
static long madvise_remove(struct vm_area_struct *vma,
				struct vm_area_struct **prev,
				unsigned long start, unsigned long end)
{
	struct address_space *mapping;
	loff_t offset, endoff;
	int error;

	*prev = NULL;	/* tell sys_madvise we drop mmap_sem */

	if (vma->vm_flags & (VM_LOCKED|VM_NONLINEAR|VM_HUGETLB))
		return -EINVAL;

	if (!vma->vm_file || !vma->vm_file->f_mapping
		|| !vma->vm_file->f_mapping->host) {
			return -EINVAL;
	}

	if ((vma->vm_flags & (VM_SHARED|VM_WRITE)) != (VM_SHARED|VM_WRITE))
		return -EACCES;

	mapping = vma->vm_file->f_mapping;

	offset = (loff_t)(start - vma->vm_start)
			+ ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
	endoff = (loff_t)(end - vma->vm_start - 1)
			+ ((loff_t)vma->vm_pgoff << PAGE_SHIFT);

	/* vmtruncate_range needs to take i_mutex and i_alloc_sem */
	up_read(&current->mm->mmap_sem);
	error = vmtruncate_range(mapping->host, offset, endoff);
	down_read(&current->mm->mmap_sem);
	return error;
}

static long
madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
		unsigned long start, unsigned long end, int behavior)
{
	long error;

	switch (behavior) {
	case MADV_DOFORK:
		if (vma->vm_flags & VM_IO) {
			error = -EINVAL;
			break;
		}
	case MADV_DONTFORK:
	case MADV_NORMAL:
	case MADV_SEQUENTIAL:
	case MADV_RANDOM:
		error = madvise_behavior(vma, prev, start, end, behavior);
		break;
	case MADV_REMOVE:
		error = madvise_remove(vma, prev, start, end);
		break;

	case MADV_WILLNEED:
		error = madvise_willneed(vma, prev, start, end);
		break;

	case MADV_DONTNEED:
		error = madvise_dontneed(vma, prev, start, end);
		break;

	default:
		error = -EINVAL;
		break;
	}
	return error;
}

/*
 * The madvise(2) system call.
 *
 * Applications can use madvise() to advise the kernel how it should
 * handle paging I/O in this VM area.  The idea is to help the kernel
 * use appropriate read-ahead and caching techniques.  The information
 * provided is advisory only, and can be safely disregarded by the
 * kernel without affecting the correct operation of the application.
 *
 * behavior values:
 *  MADV_NORMAL - the default behavior is to read clusters.  This
 *		results in some read-ahead and read-behind.
 *  MADV_RANDOM - the system should read the minimum amount of data
 *		on any access, since it is unlikely that the appli-
 *		cation will need more than what it asks for.
 *  MADV_SEQUENTIAL - pages in the given range will probably be accessed
 *		once, so they can be aggressively read ahead, and
 *		can be freed soon after they are accessed.
 *  MADV_WILLNEED - the application is notifying the system to read
 *		some pages ahead.
 *  MADV_DONTNEED - the application is finished with the given range,
 *		so the kernel can free resources associated with it.
 *  MADV_REMOVE - the application wants to free up the given range of
 *		pages and associated backing store.
 *
 * return values:
 *  zero    - success
 *  -EINVAL - start + len < 0, start is not page-aligned,
 *		"behavior" is not a valid value, or application
 *		is attempting to release locked or shared pages.
 *  -ENOMEM - addresses in the specified range are not currently
 *		mapped, or are outside the AS of the process.
 *  -EIO    - an I/O error occurred while paging in data.
 *  -EBADF  - map exists, but area maps something that isn't a file.
 *  -EAGAIN - a kernel resource was temporarily unavailable.
 */
asmlinkage long sys_madvise(unsigned long start, size_t len_in, int behavior)
{
	unsigned long end, tmp;
	struct vm_area_struct * vma, *prev;
	int unmapped_error = 0;
	int error = -EINVAL;
	size_t len;

	if (madvise_need_mmap_write(behavior))
		down_write(&current->mm->mmap_sem);
	else
		down_read(&current->mm->mmap_sem);

	if (start & ~PAGE_MASK)
		goto out;
	len = (len_in + ~PAGE_MASK) & PAGE_MASK;

	/* Check to see whether len was rounded up from small -ve to zero */
	if (len_in && !len)
		goto out;

	end = start + len;
	if (end < start)
		goto out;

	error = 0;
	if (end == start)
		goto out;

	/*
	 * If the interval [start,end) covers some unmapped address
	 * ranges, just ignore them, but return -ENOMEM at the end.
	 * - different from the way of handling in mlock etc.
	 */
	vma = find_vma_prev(current->mm, start, &prev);
	if (vma && start > vma->vm_start)
		prev = vma;

	for (;;) {
		/* Still start < end. */
		error = -ENOMEM;
		if (!vma)
			goto out;

		/* Here start < (end|vma->vm_end). */
		if (start < vma->vm_start) {
			unmapped_error = -ENOMEM;
			start = vma->vm_start;
			if (start >= end)
				goto out;
		}

		/* Here vma->vm_start <= start < (end|vma->vm_end) */
		tmp = vma->vm_end;
		if (end < tmp)
			tmp = end;

		/* Here vma->vm_start <= start < tmp <= (end|vma->vm_end). */
		error = madvise_vma(vma, &prev, start, tmp, behavior);
		if (error)
			goto out;
		start = tmp;
		if (prev && start < prev->vm_end)
			start = prev->vm_end;
		error = unmapped_error;
		if (start >= end)
			goto out;
		if (prev)
			vma = prev->vm_next;
		else	/* madvise_remove dropped mmap_sem */
			vma = find_vma(current->mm, start);
	}
out:
	if (madvise_need_mmap_write(behavior))
		up_write(&current->mm->mmap_sem);
	else
		up_read(&current->mm->mmap_sem);

	return error;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/mm/madvise.c
	3	*
	4	* Copyright (C) 1999 Linus Torvalds
	5	* Copyright (C) 2002 Christoph Hellwig
	6	*/
	7
	8	#include <linux/mman.h>
	9	#include <linux/pagemap.h>
	10	#include <linux/syscalls.h>
05b74384	11	#include <linux/mempolicy.h>
1da177e4	12	#include <linux/hugetlb.h>
e8edc6e0	13	#include <linux/sched.h>
1da177e4	14
0a27a14a NP	15	/*
	16	* Any behaviour which results in changes to the vma->vm_flags needs to
	17	* take mmap_sem for writing. Others, which simply traverse vmas, need
	18	* to only take it for reading.
	19	*/
	20	static int madvise_need_mmap_write(int behavior)
	21	{
	22	switch (behavior) {
	23	case MADV_REMOVE:
	24	case MADV_WILLNEED:
	25	case MADV_DONTNEED:
	26	return 0;
	27	default:
	28	/* be safe, default to 1. list exceptions explicitly */
	29	return 1;
	30	}
	31	}
	32
1da177e4 LT	33	/*
	34	* We can potentially split a vm area into separate
	35	* areas, each area with its own behavior.
	36	*/
05b74384 PM	37	static long madvise_behavior(struct vm_area_struct * vma,
	38	struct vm_area_struct **prev,
	39	unsigned long start, unsigned long end, int behavior)
1da177e4 LT	40	{
	41	struct mm_struct * mm = vma->vm_mm;
	42	int error = 0;
05b74384	43	pgoff_t pgoff;
f8225661	44	int new_flags = vma->vm_flags;
e798c6e8 PM	45
e798c6e8 PM	46	switch (behavior) {
f8225661 MT	47	case MADV_NORMAL:
	48	new_flags = new_flags & ~VM_RAND_READ & ~VM_SEQ_READ;
	49	break;
e798c6e8	50	case MADV_SEQUENTIAL:
f8225661	51	new_flags = (new_flags & ~VM_RAND_READ) \| VM_SEQ_READ;
e798c6e8 PM	52	break;
e798c6e8 PM	53	case MADV_RANDOM:
f8225661	54	new_flags = (new_flags & ~VM_SEQ_READ) \| VM_RAND_READ;
e798c6e8	55	break;
f8225661 MT	56	case MADV_DONTFORK:
	57	new_flags \|= VM_DONTCOPY;
	58	break;
	59	case MADV_DOFORK:
	60	new_flags &= ~VM_DONTCOPY;
e798c6e8 PM	61	break;
	62	}
	63
05b74384 PM	64	if (new_flags == vma->vm_flags) {
05b74384 PM	65	*prev = vma;
836d5ffd	66	goto out;
05b74384 PM	67	}
	68
	69	pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
	70	prev = vma_merge(mm, prev, start, end, new_flags, vma->anon_vma,
	71	vma->vm_file, pgoff, vma_policy(vma));
	72	if (*prev) {
	73	vma = *prev;
	74	goto success;
	75	}
	76
	77	*prev = vma;
1da177e4 LT	78
	79	if (start != vma->vm_start) {
	80	error = split_vma(mm, vma, start, 1);
	81	if (error)
	82	goto out;
	83	}
	84
	85	if (end != vma->vm_end) {
	86	error = split_vma(mm, vma, end, 0);
	87	if (error)
	88	goto out;
	89	}
	90
836d5ffd	91	success:
1da177e4 LT	92	/*
	93	* vm_flags is protected by the mmap_sem held in write mode.
	94	*/
e798c6e8	95	vma->vm_flags = new_flags;
1da177e4 LT	96
	97	out:
	98	if (error == -ENOMEM)
	99	error = -EAGAIN;
	100	return error;
	101	}
	102
	103	/*
	104	* Schedule all required I/O operations. Do not wait for completion.
	105	*/
	106	static long madvise_willneed(struct vm_area_struct * vma,
05b74384	107	struct vm_area_struct ** prev,
1da177e4 LT	108	unsigned long start, unsigned long end)
	109	{
	110	struct file *file = vma->vm_file;
	111
1bef4003 S	112	if (!file)
	113	return -EBADF;
	114
fe77ba6f CO	115	if (file->f_mapping->a_ops->get_xip_page) {
	116	/* no bad return value, but ignore advice */
	117	return 0;
	118	}
	119
05b74384	120	*prev = vma;
1da177e4 LT	121	start = ((start - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
	122	if (end > vma->vm_end)
	123	end = vma->vm_end;
	124	end = ((end - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
	125
	126	force_page_cache_readahead(file->f_mapping,
	127	file, start, max_sane_readahead(end - start));
	128	return 0;
	129	}
	130
	131	/*
	132	* Application no longer needs these pages. If the pages are dirty,
	133	* it's OK to just throw them away. The app will be more careful about
	134	* data it wants to keep. Be sure to free swap resources too. The
	135	* zap_page_range call sets things up for refill_inactive to actually free
	136	* these pages later if no one else has touched them in the meantime,
	137	* although we could add these pages to a global reuse list for
	138	* refill_inactive to pick up before reclaiming other pages.
	139	*
	140	* NB: This interface discards data rather than pushes it out to swap,
	141	* as some implementations do. This has performance implications for
	142	* applications like large transactional databases which want to discard
	143	* pages in anonymous maps after committing to backing store the data
	144	* that was kept in them. There is no reason to write this data out to
	145	* the swap area if the application is discarding it.
	146	*
	147	* An interface that causes the system to free clean pages and flush
	148	* dirty pages is already available as msync(MS_INVALIDATE).
	149	*/
	150	static long madvise_dontneed(struct vm_area_struct * vma,
05b74384	151	struct vm_area_struct ** prev,
1da177e4 LT	152	unsigned long start, unsigned long end)
1da177e4 LT	153	{
05b74384	154	*prev = vma;
6aab341e	155	if (vma->vm_flags & (VM_LOCKED\|VM_HUGETLB\|VM_PFNMAP))
1da177e4 LT	156	return -EINVAL;
	157
	158	if (unlikely(vma->vm_flags & VM_NONLINEAR)) {
	159	struct zap_details details = {
	160	.nonlinear_vma = vma,
	161	.last_index = ULONG_MAX,
	162	};
	163	zap_page_range(vma, start, end - start, &details);
	164	} else
	165	zap_page_range(vma, start, end - start, NULL);
	166	return 0;
	167	}
	168
f6b3ec23 BP	169	/*
	170	* Application wants to free up the pages and associated backing store.
	171	* This is effectively punching a hole into the middle of a file.
	172	*
	173	* NOTE: Currently, only shmfs/tmpfs is supported for this operation.
	174	* Other filesystems return -ENOSYS.
	175	*/
	176	static long madvise_remove(struct vm_area_struct *vma,
00e9fa2d	177	struct vm_area_struct **prev,
f6b3ec23 BP	178	unsigned long start, unsigned long end)
	179	{
	180	struct address_space *mapping;
90ed52eb HD	181	loff_t offset, endoff;
90ed52eb HD	182	int error;
f6b3ec23	183
90ed52eb	184	prev = NULL; / tell sys_madvise we drop mmap_sem */
00e9fa2d	185
f6b3ec23 BP	186	if (vma->vm_flags & (VM_LOCKED\|VM_NONLINEAR\|VM_HUGETLB))
	187	return -EINVAL;
	188
	189	if (!vma->vm_file \|\| !vma->vm_file->f_mapping
	190	\|\| !vma->vm_file->f_mapping->host) {
	191	return -EINVAL;
	192	}
	193
69cf0fac HD	194	if ((vma->vm_flags & (VM_SHARED\|VM_WRITE)) != (VM_SHARED\|VM_WRITE))
	195	return -EACCES;
	196
f6b3ec23 BP	197	mapping = vma->vm_file->f_mapping;
	198
	199	offset = (loff_t)(start - vma->vm_start)
	200	+ ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
	201	endoff = (loff_t)(end - vma->vm_start - 1)
	202	+ ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
90ed52eb HD	203
90ed52eb HD	204	/* vmtruncate_range needs to take i_mutex and i_alloc_sem */
0a27a14a	205	up_read(&current->mm->mmap_sem);
90ed52eb	206	error = vmtruncate_range(mapping->host, offset, endoff);
0a27a14a	207	down_read(&current->mm->mmap_sem);
90ed52eb	208	return error;
f6b3ec23 BP	209	}
f6b3ec23 BP	210
165cd402	211	static long
	212	madvise_vma(struct vm_area_struct vma, struct vm_area_struct *prev,
	213	unsigned long start, unsigned long end, int behavior)
1da177e4	214	{
1bef4003	215	long error;
165cd402	216
1da177e4	217	switch (behavior) {
f8225661 MT	218	case MADV_DOFORK:
	219	if (vma->vm_flags & VM_IO) {
	220	error = -EINVAL;
	221	break;
	222	}
	223	case MADV_DONTFORK:
1da177e4 LT	224	case MADV_NORMAL:
	225	case MADV_SEQUENTIAL:
	226	case MADV_RANDOM:
05b74384	227	error = madvise_behavior(vma, prev, start, end, behavior);
1da177e4	228	break;
f6b3ec23	229	case MADV_REMOVE:
00e9fa2d	230	error = madvise_remove(vma, prev, start, end);
f6b3ec23	231	break;
1da177e4 LT	232
1da177e4 LT	233	case MADV_WILLNEED:
05b74384	234	error = madvise_willneed(vma, prev, start, end);
1da177e4 LT	235	break;
	236
	237	case MADV_DONTNEED:
05b74384	238	error = madvise_dontneed(vma, prev, start, end);
1da177e4 LT	239	break;
	240
	241	default:
	242	error = -EINVAL;
	243	break;
	244	}
1da177e4 LT	245	return error;
	246	}
	247
	248	/*
	249	* The madvise(2) system call.
	250	*
	251	* Applications can use madvise() to advise the kernel how it should
	252	* handle paging I/O in this VM area. The idea is to help the kernel
	253	* use appropriate read-ahead and caching techniques. The information
	254	* provided is advisory only, and can be safely disregarded by the
	255	* kernel without affecting the correct operation of the application.
	256	*
	257	* behavior values:
	258	* MADV_NORMAL - the default behavior is to read clusters. This
	259	* results in some read-ahead and read-behind.
	260	* MADV_RANDOM - the system should read the minimum amount of data
	261	* on any access, since it is unlikely that the appli-
	262	* cation will need more than what it asks for.
	263	* MADV_SEQUENTIAL - pages in the given range will probably be accessed
	264	* once, so they can be aggressively read ahead, and
	265	* can be freed soon after they are accessed.
	266	* MADV_WILLNEED - the application is notifying the system to read
	267	* some pages ahead.
	268	* MADV_DONTNEED - the application is finished with the given range,
	269	* so the kernel can free resources associated with it.
f6b3ec23 BP	270	* MADV_REMOVE - the application wants to free up the given range of
f6b3ec23 BP	271	* pages and associated backing store.
1da177e4 LT	272	*
	273	* return values:
	274	* zero - success
	275	* -EINVAL - start + len < 0, start is not page-aligned,
	276	* "behavior" is not a valid value, or application
	277	* is attempting to release locked or shared pages.
	278	* -ENOMEM - addresses in the specified range are not currently
	279	* mapped, or are outside the AS of the process.
	280	* -EIO - an I/O error occurred while paging in data.
	281	* -EBADF - map exists, but area maps something that isn't a file.
	282	* -EAGAIN - a kernel resource was temporarily unavailable.
	283	*/
	284	asmlinkage long sys_madvise(unsigned long start, size_t len_in, int behavior)
	285	{
05b74384 PM	286	unsigned long end, tmp;
05b74384 PM	287	struct vm_area_struct * vma, *prev;
1da177e4 LT	288	int unmapped_error = 0;
	289	int error = -EINVAL;
	290	size_t len;
	291
0a27a14a NP	292	if (madvise_need_mmap_write(behavior))
	293	down_write(&current->mm->mmap_sem);
	294	else
	295	down_read(&current->mm->mmap_sem);
1da177e4 LT	296
	297	if (start & ~PAGE_MASK)
	298	goto out;
	299	len = (len_in + ~PAGE_MASK) & PAGE_MASK;
	300
	301	/* Check to see whether len was rounded up from small -ve to zero */
	302	if (len_in && !len)
	303	goto out;
	304
	305	end = start + len;
	306	if (end < start)
	307	goto out;
	308
	309	error = 0;
	310	if (end == start)
	311	goto out;
	312
	313	/*
	314	* If the interval [start,end) covers some unmapped address
	315	* ranges, just ignore them, but return -ENOMEM at the end.
05b74384	316	* - different from the way of handling in mlock etc.
1da177e4	317	*/
05b74384	318	vma = find_vma_prev(current->mm, start, &prev);
836d5ffd HD	319	if (vma && start > vma->vm_start)
	320	prev = vma;
	321
1da177e4 LT	322	for (;;) {
	323	/* Still start < end. */
	324	error = -ENOMEM;
	325	if (!vma)
	326	goto out;
	327
05b74384	328	/* Here start < (end\|vma->vm_end). */
1da177e4 LT	329	if (start < vma->vm_start) {
	330	unmapped_error = -ENOMEM;
	331	start = vma->vm_start;
05b74384 PM	332	if (start >= end)
05b74384 PM	333	goto out;
1da177e4 LT	334	}
1da177e4 LT	335
05b74384 PM	336	/* Here vma->vm_start <= start < (end\|vma->vm_end) */
	337	tmp = vma->vm_end;
	338	if (end < tmp)
	339	tmp = end;
1da177e4	340
05b74384 PM	341	/* Here vma->vm_start <= start < tmp <= (end\|vma->vm_end). */
05b74384 PM	342	error = madvise_vma(vma, &prev, start, tmp, behavior);
1da177e4 LT	343	if (error)
1da177e4 LT	344	goto out;
05b74384	345	start = tmp;
90ed52eb	346	if (prev && start < prev->vm_end)
05b74384 PM	347	start = prev->vm_end;
	348	error = unmapped_error;
	349	if (start >= end)
	350	goto out;
90ed52eb HD	351	if (prev)
	352	vma = prev->vm_next;
	353	else /* madvise_remove dropped mmap_sem */
	354	vma = find_vma(current->mm, start);
1da177e4	355	}
1da177e4	356	out:
0a27a14a NP	357	if (madvise_need_mmap_write(behavior))
	358	up_write(&current->mm->mmap_sem);
	359	else
	360	up_read(&current->mm->mmap_sem);
	361
1da177e4 LT	362	return error;
1da177e4 LT	363	}