[mirror_ubuntu-bionic-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/page-isolation.h>
#include <linux/hugetlb.h>
#include <linux/sched.h>
#include <linux/ksm.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;
	unsigned long 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:
		if (vma->vm_flags & VM_IO) {
			error = -EINVAL;
			goto out;
		}
		new_flags &= ~VM_DONTCOPY;
		break;
	case MADV_MERGEABLE:
	case MADV_UNMERGEABLE:
		error = ksm_madvise(vma, start, end, behavior, &new_flags);
		if (error)
			goto out;
		break;
	case MADV_HUGEPAGE:
		error = hugepage_madvise(&new_flags);
		if (error)
			goto out;
		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_mem) {
		/* 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, 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 shrink_active_list 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
 * shrink_active_list 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;
}

#ifdef CONFIG_MEMORY_FAILURE
/*
 * Error injection support for memory error handling.
 */
static int madvise_hwpoison(int bhv, unsigned long start, unsigned long end)
{
	int ret = 0;

	if (!capable(CAP_SYS_ADMIN))
		return -EPERM;
	for (; start < end; start += PAGE_SIZE) {
		struct page *p;
		int ret = get_user_pages_fast(start, 1, 0, &p);
		if (ret != 1)
			return ret;
		if (bhv == MADV_SOFT_OFFLINE) {
			printk(KERN_INFO "Soft offlining page %lx at %lx\n",
				page_to_pfn(p), start);
			ret = soft_offline_page(p, MF_COUNT_INCREASED);
			if (ret)
				break;
			continue;
		}
		printk(KERN_INFO "Injecting memory failure for page %lx at %lx\n",
		       page_to_pfn(p), start);
		/* Ignore return value for now */
		__memory_failure(page_to_pfn(p), 0, MF_COUNT_INCREASED);
	}
	return ret;
}
#endif

static long
madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
		unsigned long start, unsigned long end, int behavior)
{
	switch (behavior) {
	case MADV_REMOVE:
		return madvise_remove(vma, prev, start, end);
	case MADV_WILLNEED:
		return madvise_willneed(vma, prev, start, end);
	case MADV_DONTNEED:
		return madvise_dontneed(vma, prev, start, end);
	default:
		return madvise_behavior(vma, prev, start, end, behavior);
	}
}

static int
madvise_behavior_valid(int behavior)
{
	switch (behavior) {
	case MADV_DOFORK:
	case MADV_DONTFORK:
	case MADV_NORMAL:
	case MADV_SEQUENTIAL:
	case MADV_RANDOM:
	case MADV_REMOVE:
	case MADV_WILLNEED:
	case MADV_DONTNEED:
#ifdef CONFIG_KSM
	case MADV_MERGEABLE:
	case MADV_UNMERGEABLE:
#endif
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	case MADV_HUGEPAGE:
#endif
		return 1;

	default:
		return 0;
	}
}

/*
 * 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.
 *  MADV_DONTFORK - omit this area from child's address space when forking:
 *		typically, to avoid COWing pages pinned by get_user_pages().
 *  MADV_DOFORK - cancel MADV_DONTFORK: no longer omit this area when forking.
 *  MADV_MERGEABLE - the application recommends that KSM try to merge pages in
 *		this area with pages of identical content from other such areas.
 *  MADV_UNMERGEABLE- cancel MADV_MERGEABLE: no longer merge pages with others.
 *
 * 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.
 */
SYSCALL_DEFINE3(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;
	int write;
	size_t len;

#ifdef CONFIG_MEMORY_FAILURE
	if (behavior == MADV_HWPOISON || behavior == MADV_SOFT_OFFLINE)
		return madvise_hwpoison(behavior, start, start+len_in);
#endif
	if (!madvise_behavior_valid(behavior))
		return error;

	write = madvise_need_mmap_write(behavior);
	if (write)
		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 (write)
		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>
afcf938e	12	#include <linux/page-isolation.h>
1da177e4	13	#include <linux/hugetlb.h>
e8edc6e0	14	#include <linux/sched.h>
f8af4da3	15	#include <linux/ksm.h>
1da177e4	16
0a27a14a NP	17	/*
	18	* Any behaviour which results in changes to the vma->vm_flags needs to
	19	* take mmap_sem for writing. Others, which simply traverse vmas, need
	20	* to only take it for reading.
	21	*/
	22	static int madvise_need_mmap_write(int behavior)
	23	{
	24	switch (behavior) {
	25	case MADV_REMOVE:
	26	case MADV_WILLNEED:
	27	case MADV_DONTNEED:
	28	return 0;
	29	default:
	30	/* be safe, default to 1. list exceptions explicitly */
	31	return 1;
	32	}
	33	}
	34
1da177e4 LT	35	/*
	36	* We can potentially split a vm area into separate
	37	* areas, each area with its own behavior.
	38	*/
05b74384 PM	39	static long madvise_behavior(struct vm_area_struct * vma,
	40	struct vm_area_struct **prev,
	41	unsigned long start, unsigned long end, int behavior)
1da177e4 LT	42	{
	43	struct mm_struct * mm = vma->vm_mm;
	44	int error = 0;
05b74384	45	pgoff_t pgoff;
3866ea90	46	unsigned long new_flags = vma->vm_flags;
e798c6e8 PM	47
e798c6e8 PM	48	switch (behavior) {
f8225661 MT	49	case MADV_NORMAL:
	50	new_flags = new_flags & ~VM_RAND_READ & ~VM_SEQ_READ;
	51	break;
e798c6e8	52	case MADV_SEQUENTIAL:
f8225661	53	new_flags = (new_flags & ~VM_RAND_READ) \| VM_SEQ_READ;
e798c6e8 PM	54	break;
e798c6e8 PM	55	case MADV_RANDOM:
f8225661	56	new_flags = (new_flags & ~VM_SEQ_READ) \| VM_RAND_READ;
e798c6e8	57	break;
f8225661 MT	58	case MADV_DONTFORK:
	59	new_flags \|= VM_DONTCOPY;
	60	break;
	61	case MADV_DOFORK:
3866ea90 HD	62	if (vma->vm_flags & VM_IO) {
	63	error = -EINVAL;
	64	goto out;
	65	}
f8225661	66	new_flags &= ~VM_DONTCOPY;
e798c6e8	67	break;
f8af4da3 HD	68	case MADV_MERGEABLE:
	69	case MADV_UNMERGEABLE:
	70	error = ksm_madvise(vma, start, end, behavior, &new_flags);
	71	if (error)
	72	goto out;
	73	break;
0af4e98b AA	74	case MADV_HUGEPAGE:
	75	error = hugepage_madvise(&new_flags);
	76	if (error)
	77	goto out;
	78	break;
e798c6e8 PM	79	}
e798c6e8 PM	80
05b74384 PM	81	if (new_flags == vma->vm_flags) {
05b74384 PM	82	*prev = vma;
836d5ffd	83	goto out;
05b74384 PM	84	}
	85
	86	pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
	87	prev = vma_merge(mm, prev, start, end, new_flags, vma->anon_vma,
	88	vma->vm_file, pgoff, vma_policy(vma));
	89	if (*prev) {
	90	vma = *prev;
	91	goto success;
	92	}
	93
	94	*prev = vma;
1da177e4 LT	95
	96	if (start != vma->vm_start) {
	97	error = split_vma(mm, vma, start, 1);
	98	if (error)
	99	goto out;
	100	}
	101
	102	if (end != vma->vm_end) {
	103	error = split_vma(mm, vma, end, 0);
	104	if (error)
	105	goto out;
	106	}
	107
836d5ffd	108	success:
1da177e4 LT	109	/*
	110	* vm_flags is protected by the mmap_sem held in write mode.
	111	*/
e798c6e8	112	vma->vm_flags = new_flags;
1da177e4 LT	113
	114	out:
	115	if (error == -ENOMEM)
	116	error = -EAGAIN;
	117	return error;
	118	}
	119
	120	/*
	121	* Schedule all required I/O operations. Do not wait for completion.
	122	*/
	123	static long madvise_willneed(struct vm_area_struct * vma,
05b74384	124	struct vm_area_struct ** prev,
1da177e4 LT	125	unsigned long start, unsigned long end)
	126	{
	127	struct file *file = vma->vm_file;
	128
1bef4003 S	129	if (!file)
	130	return -EBADF;
	131
70688e4d	132	if (file->f_mapping->a_ops->get_xip_mem) {
fe77ba6f CO	133	/* no bad return value, but ignore advice */
	134	return 0;
	135	}
	136
05b74384	137	*prev = vma;
1da177e4 LT	138	start = ((start - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
	139	if (end > vma->vm_end)
	140	end = vma->vm_end;
	141	end = ((end - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
	142
f7e839dd	143	force_page_cache_readahead(file->f_mapping, file, start, end - start);
1da177e4 LT	144	return 0;
	145	}
	146
	147	/*
	148	* Application no longer needs these pages. If the pages are dirty,
	149	* it's OK to just throw them away. The app will be more careful about
	150	* data it wants to keep. Be sure to free swap resources too. The
7e6cbea3	151	* zap_page_range call sets things up for shrink_active_list to actually free
1da177e4 LT	152	* these pages later if no one else has touched them in the meantime,
1da177e4 LT	153	* although we could add these pages to a global reuse list for
7e6cbea3	154	* shrink_active_list to pick up before reclaiming other pages.
1da177e4 LT	155	*
	156	* NB: This interface discards data rather than pushes it out to swap,
	157	* as some implementations do. This has performance implications for
	158	* applications like large transactional databases which want to discard
	159	* pages in anonymous maps after committing to backing store the data
	160	* that was kept in them. There is no reason to write this data out to
	161	* the swap area if the application is discarding it.
	162	*
	163	* An interface that causes the system to free clean pages and flush
	164	* dirty pages is already available as msync(MS_INVALIDATE).
	165	*/
	166	static long madvise_dontneed(struct vm_area_struct * vma,
05b74384	167	struct vm_area_struct ** prev,
1da177e4 LT	168	unsigned long start, unsigned long end)
1da177e4 LT	169	{
05b74384	170	*prev = vma;
6aab341e	171	if (vma->vm_flags & (VM_LOCKED\|VM_HUGETLB\|VM_PFNMAP))
1da177e4 LT	172	return -EINVAL;
	173
	174	if (unlikely(vma->vm_flags & VM_NONLINEAR)) {
	175	struct zap_details details = {
	176	.nonlinear_vma = vma,
	177	.last_index = ULONG_MAX,
	178	};
	179	zap_page_range(vma, start, end - start, &details);
	180	} else
	181	zap_page_range(vma, start, end - start, NULL);
	182	return 0;
	183	}
	184
f6b3ec23 BP	185	/*
	186	* Application wants to free up the pages and associated backing store.
	187	* This is effectively punching a hole into the middle of a file.
	188	*
	189	* NOTE: Currently, only shmfs/tmpfs is supported for this operation.
	190	* Other filesystems return -ENOSYS.
	191	*/
	192	static long madvise_remove(struct vm_area_struct *vma,
00e9fa2d	193	struct vm_area_struct **prev,
f6b3ec23 BP	194	unsigned long start, unsigned long end)
	195	{
	196	struct address_space *mapping;
90ed52eb HD	197	loff_t offset, endoff;
90ed52eb HD	198	int error;
f6b3ec23	199
90ed52eb	200	prev = NULL; / tell sys_madvise we drop mmap_sem */
00e9fa2d	201
f6b3ec23 BP	202	if (vma->vm_flags & (VM_LOCKED\|VM_NONLINEAR\|VM_HUGETLB))
	203	return -EINVAL;
	204
	205	if (!vma->vm_file \|\| !vma->vm_file->f_mapping
	206	\|\| !vma->vm_file->f_mapping->host) {
	207	return -EINVAL;
	208	}
	209
69cf0fac HD	210	if ((vma->vm_flags & (VM_SHARED\|VM_WRITE)) != (VM_SHARED\|VM_WRITE))
	211	return -EACCES;
	212
f6b3ec23 BP	213	mapping = vma->vm_file->f_mapping;
	214
	215	offset = (loff_t)(start - vma->vm_start)
	216	+ ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
	217	endoff = (loff_t)(end - vma->vm_start - 1)
	218	+ ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
90ed52eb HD	219
90ed52eb HD	220	/* vmtruncate_range needs to take i_mutex and i_alloc_sem */
0a27a14a	221	up_read(&current->mm->mmap_sem);
90ed52eb	222	error = vmtruncate_range(mapping->host, offset, endoff);
0a27a14a	223	down_read(&current->mm->mmap_sem);
90ed52eb	224	return error;
f6b3ec23 BP	225	}
f6b3ec23 BP	226
9893e49d AK	227	#ifdef CONFIG_MEMORY_FAILURE
	228	/*
	229	* Error injection support for memory error handling.
	230	*/
afcf938e	231	static int madvise_hwpoison(int bhv, unsigned long start, unsigned long end)
9893e49d AK	232	{
	233	int ret = 0;
	234
	235	if (!capable(CAP_SYS_ADMIN))
	236	return -EPERM;
	237	for (; start < end; start += PAGE_SIZE) {
	238	struct page *p;
d15f107d	239	int ret = get_user_pages_fast(start, 1, 0, &p);
9893e49d AK	240	if (ret != 1)
9893e49d AK	241	return ret;
afcf938e AK	242	if (bhv == MADV_SOFT_OFFLINE) {
	243	printk(KERN_INFO "Soft offlining page %lx at %lx\n",
	244	page_to_pfn(p), start);
	245	ret = soft_offline_page(p, MF_COUNT_INCREASED);
	246	if (ret)
	247	break;
	248	continue;
	249	}
9893e49d AK	250	printk(KERN_INFO "Injecting memory failure for page %lx at %lx\n",
	251	page_to_pfn(p), start);
	252	/* Ignore return value for now */
82ba011b	253	__memory_failure(page_to_pfn(p), 0, MF_COUNT_INCREASED);
9893e49d AK	254	}
	255	return ret;
	256	}
	257	#endif
	258
165cd402	259	static long
	260	madvise_vma(struct vm_area_struct vma, struct vm_area_struct *prev,
	261	unsigned long start, unsigned long end, int behavior)
1da177e4	262	{
1da177e4	263	switch (behavior) {
f6b3ec23	264	case MADV_REMOVE:
3866ea90	265	return madvise_remove(vma, prev, start, end);
1da177e4	266	case MADV_WILLNEED:
3866ea90	267	return madvise_willneed(vma, prev, start, end);
1da177e4	268	case MADV_DONTNEED:
3866ea90	269	return madvise_dontneed(vma, prev, start, end);
1da177e4	270	default:
3866ea90	271	return madvise_behavior(vma, prev, start, end, behavior);
1da177e4	272	}
1da177e4 LT	273	}
1da177e4 LT	274
75927af8 NP	275	static int
	276	madvise_behavior_valid(int behavior)
	277	{
	278	switch (behavior) {
	279	case MADV_DOFORK:
	280	case MADV_DONTFORK:
	281	case MADV_NORMAL:
	282	case MADV_SEQUENTIAL:
	283	case MADV_RANDOM:
	284	case MADV_REMOVE:
	285	case MADV_WILLNEED:
	286	case MADV_DONTNEED:
f8af4da3 HD	287	#ifdef CONFIG_KSM
	288	case MADV_MERGEABLE:
	289	case MADV_UNMERGEABLE:
0af4e98b AA	290	#endif
	291	#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	292	case MADV_HUGEPAGE:
f8af4da3	293	#endif
75927af8 NP	294	return 1;
	295
	296	default:
	297	return 0;
	298	}
	299	}
3866ea90	300
1da177e4 LT	301	/*
	302	* The madvise(2) system call.
	303	*
	304	* Applications can use madvise() to advise the kernel how it should
	305	* handle paging I/O in this VM area. The idea is to help the kernel
	306	* use appropriate read-ahead and caching techniques. The information
	307	* provided is advisory only, and can be safely disregarded by the
	308	* kernel without affecting the correct operation of the application.
	309	*
	310	* behavior values:
	311	* MADV_NORMAL - the default behavior is to read clusters. This
	312	* results in some read-ahead and read-behind.
	313	* MADV_RANDOM - the system should read the minimum amount of data
	314	* on any access, since it is unlikely that the appli-
	315	* cation will need more than what it asks for.
	316	* MADV_SEQUENTIAL - pages in the given range will probably be accessed
	317	* once, so they can be aggressively read ahead, and
	318	* can be freed soon after they are accessed.
	319	* MADV_WILLNEED - the application is notifying the system to read
	320	* some pages ahead.
	321	* MADV_DONTNEED - the application is finished with the given range,
	322	* so the kernel can free resources associated with it.
f6b3ec23 BP	323	* MADV_REMOVE - the application wants to free up the given range of
f6b3ec23 BP	324	* pages and associated backing store.
3866ea90 HD	325	* MADV_DONTFORK - omit this area from child's address space when forking:
	326	* typically, to avoid COWing pages pinned by get_user_pages().
	327	* MADV_DOFORK - cancel MADV_DONTFORK: no longer omit this area when forking.
f8af4da3 HD	328	* MADV_MERGEABLE - the application recommends that KSM try to merge pages in
	329	* this area with pages of identical content from other such areas.
	330	* MADV_UNMERGEABLE- cancel MADV_MERGEABLE: no longer merge pages with others.
1da177e4 LT	331	*
	332	* return values:
	333	* zero - success
	334	* -EINVAL - start + len < 0, start is not page-aligned,
	335	* "behavior" is not a valid value, or application
	336	* is attempting to release locked or shared pages.
	337	* -ENOMEM - addresses in the specified range are not currently
	338	* mapped, or are outside the AS of the process.
	339	* -EIO - an I/O error occurred while paging in data.
	340	* -EBADF - map exists, but area maps something that isn't a file.
	341	* -EAGAIN - a kernel resource was temporarily unavailable.
	342	*/
3480b257	343	SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
1da177e4	344	{
05b74384 PM	345	unsigned long end, tmp;
05b74384 PM	346	struct vm_area_struct * vma, *prev;
1da177e4 LT	347	int unmapped_error = 0;
1da177e4 LT	348	int error = -EINVAL;
f7977793	349	int write;
1da177e4 LT	350	size_t len;
1da177e4 LT	351
9893e49d	352	#ifdef CONFIG_MEMORY_FAILURE
afcf938e AK	353	if (behavior == MADV_HWPOISON \|\| behavior == MADV_SOFT_OFFLINE)
afcf938e AK	354	return madvise_hwpoison(behavior, start, start+len_in);
9893e49d	355	#endif
75927af8 NP	356	if (!madvise_behavior_valid(behavior))
	357	return error;
	358
f7977793 JB	359	write = madvise_need_mmap_write(behavior);
f7977793 JB	360	if (write)
0a27a14a NP	361	down_write(&current->mm->mmap_sem);
	362	else
	363	down_read(&current->mm->mmap_sem);
1da177e4 LT	364
	365	if (start & ~PAGE_MASK)
	366	goto out;
	367	len = (len_in + ~PAGE_MASK) & PAGE_MASK;
	368
	369	/* Check to see whether len was rounded up from small -ve to zero */
	370	if (len_in && !len)
	371	goto out;
	372
	373	end = start + len;
	374	if (end < start)
	375	goto out;
	376
	377	error = 0;
	378	if (end == start)
	379	goto out;
	380
	381	/*
	382	* If the interval [start,end) covers some unmapped address
	383	* ranges, just ignore them, but return -ENOMEM at the end.
05b74384	384	* - different from the way of handling in mlock etc.
1da177e4	385	*/
05b74384	386	vma = find_vma_prev(current->mm, start, &prev);
836d5ffd HD	387	if (vma && start > vma->vm_start)
	388	prev = vma;
	389
1da177e4 LT	390	for (;;) {
	391	/* Still start < end. */
	392	error = -ENOMEM;
	393	if (!vma)
	394	goto out;
	395
05b74384	396	/* Here start < (end\|vma->vm_end). */
1da177e4 LT	397	if (start < vma->vm_start) {
	398	unmapped_error = -ENOMEM;
	399	start = vma->vm_start;
05b74384 PM	400	if (start >= end)
05b74384 PM	401	goto out;
1da177e4 LT	402	}
1da177e4 LT	403
05b74384 PM	404	/* Here vma->vm_start <= start < (end\|vma->vm_end) */
	405	tmp = vma->vm_end;
	406	if (end < tmp)
	407	tmp = end;
1da177e4	408
05b74384 PM	409	/* Here vma->vm_start <= start < tmp <= (end\|vma->vm_end). */
05b74384 PM	410	error = madvise_vma(vma, &prev, start, tmp, behavior);
1da177e4 LT	411	if (error)
1da177e4 LT	412	goto out;
05b74384	413	start = tmp;
90ed52eb	414	if (prev && start < prev->vm_end)
05b74384 PM	415	start = prev->vm_end;
	416	error = unmapped_error;
	417	if (start >= end)
	418	goto out;
90ed52eb HD	419	if (prev)
	420	vma = prev->vm_next;
	421	else /* madvise_remove dropped mmap_sem */
	422	vma = find_vma(current->mm, start);
1da177e4	423	}
1da177e4	424	out:
f7977793	425	if (write)
0a27a14a NP	426	up_write(&current->mm->mmap_sem);
	427	else
	428	up_read(&current->mm->mmap_sem);
	429
1da177e4 LT	430	return error;
1da177e4 LT	431	}