[mirror_ubuntu-artful-kernel.git] / mm / util.c

#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/compiler.h>
#include <linux/export.h>
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/security.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/mman.h>
#include <linux/hugetlb.h>
#include <linux/vmalloc.h>

#include <asm/sections.h>
#include <asm/uaccess.h>

#include "internal.h"

static inline int is_kernel_rodata(unsigned long addr)
{
	return addr >= (unsigned long)__start_rodata &&
		addr < (unsigned long)__end_rodata;
}

/**
 * kfree_const - conditionally free memory
 * @x: pointer to the memory
 *
 * Function calls kfree only if @x is not in .rodata section.
 */
void kfree_const(const void *x)
{
	if (!is_kernel_rodata((unsigned long)x))
		kfree(x);
}
EXPORT_SYMBOL(kfree_const);

/**
 * kstrdup - allocate space for and copy an existing string
 * @s: the string to duplicate
 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
 */
char *kstrdup(const char *s, gfp_t gfp)
{
	size_t len;
	char *buf;

	if (!s)
		return NULL;

	len = strlen(s) + 1;
	buf = kmalloc_track_caller(len, gfp);
	if (buf)
		memcpy(buf, s, len);
	return buf;
}
EXPORT_SYMBOL(kstrdup);

/**
 * kstrdup_const - conditionally duplicate an existing const string
 * @s: the string to duplicate
 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
 *
 * Function returns source string if it is in .rodata section otherwise it
 * fallbacks to kstrdup.
 * Strings allocated by kstrdup_const should be freed by kfree_const.
 */
const char *kstrdup_const(const char *s, gfp_t gfp)
{
	if (is_kernel_rodata((unsigned long)s))
		return s;

	return kstrdup(s, gfp);
}
EXPORT_SYMBOL(kstrdup_const);

/**
 * kstrndup - allocate space for and copy an existing string
 * @s: the string to duplicate
 * @max: read at most @max chars from @s
 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
 */
char *kstrndup(const char *s, size_t max, gfp_t gfp)
{
	size_t len;
	char *buf;

	if (!s)
		return NULL;

	len = strnlen(s, max);
	buf = kmalloc_track_caller(len+1, gfp);
	if (buf) {
		memcpy(buf, s, len);
		buf[len] = '\0';
	}
	return buf;
}
EXPORT_SYMBOL(kstrndup);

/**
 * kmemdup - duplicate region of memory
 *
 * @src: memory region to duplicate
 * @len: memory region length
 * @gfp: GFP mask to use
 */
void *kmemdup(const void *src, size_t len, gfp_t gfp)
{
	void *p;

	p = kmalloc_track_caller(len, gfp);
	if (p)
		memcpy(p, src, len);
	return p;
}
EXPORT_SYMBOL(kmemdup);

/**
 * memdup_user - duplicate memory region from user space
 *
 * @src: source address in user space
 * @len: number of bytes to copy
 *
 * Returns an ERR_PTR() on failure.
 */
void *memdup_user(const void __user *src, size_t len)
{
	void *p;

	/*
	 * Always use GFP_KERNEL, since copy_from_user() can sleep and
	 * cause pagefault, which makes it pointless to use GFP_NOFS
	 * or GFP_ATOMIC.
	 */
	p = kmalloc_track_caller(len, GFP_KERNEL);
	if (!p)
		return ERR_PTR(-ENOMEM);

	if (copy_from_user(p, src, len)) {
		kfree(p);
		return ERR_PTR(-EFAULT);
	}

	return p;
}
EXPORT_SYMBOL(memdup_user);

/*
 * strndup_user - duplicate an existing string from user space
 * @s: The string to duplicate
 * @n: Maximum number of bytes to copy, including the trailing NUL.
 */
char *strndup_user(const char __user *s, long n)
{
	char *p;
	long length;

	length = strnlen_user(s, n);

	if (!length)
		return ERR_PTR(-EFAULT);

	if (length > n)
		return ERR_PTR(-EINVAL);

	p = memdup_user(s, length);

	if (IS_ERR(p))
		return p;

	p[length - 1] = '\0';

	return p;
}
EXPORT_SYMBOL(strndup_user);

/**
 * memdup_user_nul - duplicate memory region from user space and NUL-terminate
 *
 * @src: source address in user space
 * @len: number of bytes to copy
 *
 * Returns an ERR_PTR() on failure.
 */
void *memdup_user_nul(const void __user *src, size_t len)
{
	char *p;

	/*
	 * Always use GFP_KERNEL, since copy_from_user() can sleep and
	 * cause pagefault, which makes it pointless to use GFP_NOFS
	 * or GFP_ATOMIC.
	 */
	p = kmalloc_track_caller(len + 1, GFP_KERNEL);
	if (!p)
		return ERR_PTR(-ENOMEM);

	if (copy_from_user(p, src, len)) {
		kfree(p);
		return ERR_PTR(-EFAULT);
	}
	p[len] = '\0';

	return p;
}
EXPORT_SYMBOL(memdup_user_nul);

void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
		struct vm_area_struct *prev, struct rb_node *rb_parent)
{
	struct vm_area_struct *next;

	vma->vm_prev = prev;
	if (prev) {
		next = prev->vm_next;
		prev->vm_next = vma;
	} else {
		mm->mmap = vma;
		if (rb_parent)
			next = rb_entry(rb_parent,
					struct vm_area_struct, vm_rb);
		else
			next = NULL;
	}
	vma->vm_next = next;
	if (next)
		next->vm_prev = vma;
}

/* Check if the vma is being used as a stack by this task */
int vma_is_stack_for_task(struct vm_area_struct *vma, struct task_struct *t)
{
	return (vma->vm_start <= KSTK_ESP(t) && vma->vm_end >= KSTK_ESP(t));
}

#if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)
void arch_pick_mmap_layout(struct mm_struct *mm)
{
	mm->mmap_base = TASK_UNMAPPED_BASE;
	mm->get_unmapped_area = arch_get_unmapped_area;
}
#endif

/*
 * Like get_user_pages_fast() except its IRQ-safe in that it won't fall
 * back to the regular GUP.
 * If the architecture not support this function, simply return with no
 * page pinned
 */
int __weak __get_user_pages_fast(unsigned long start,
				 int nr_pages, int write, struct page **pages)
{
	return 0;
}
EXPORT_SYMBOL_GPL(__get_user_pages_fast);

/**
 * get_user_pages_fast() - pin user pages in memory
 * @start:	starting user address
 * @nr_pages:	number of pages from start to pin
 * @write:	whether pages will be written to
 * @pages:	array that receives pointers to the pages pinned.
 *		Should be at least nr_pages long.
 *
 * Returns number of pages pinned. This may be fewer than the number
 * requested. If nr_pages is 0 or negative, returns 0. If no pages
 * were pinned, returns -errno.
 *
 * get_user_pages_fast provides equivalent functionality to get_user_pages,
 * operating on current and current->mm, with force=0 and vma=NULL. However
 * unlike get_user_pages, it must be called without mmap_sem held.
 *
 * get_user_pages_fast may take mmap_sem and page table locks, so no
 * assumptions can be made about lack of locking. get_user_pages_fast is to be
 * implemented in a way that is advantageous (vs get_user_pages()) when the
 * user memory area is already faulted in and present in ptes. However if the
 * pages have to be faulted in, it may turn out to be slightly slower so
 * callers need to carefully consider what to use. On many architectures,
 * get_user_pages_fast simply falls back to get_user_pages.
 */
int __weak get_user_pages_fast(unsigned long start,
				int nr_pages, int write, struct page **pages)
{
	return get_user_pages_unlocked(start, nr_pages, write, 0, pages);
}
EXPORT_SYMBOL_GPL(get_user_pages_fast);

unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr,
	unsigned long len, unsigned long prot,
	unsigned long flag, unsigned long pgoff)
{
	unsigned long ret;
	struct mm_struct *mm = current->mm;
	unsigned long populate;

	ret = security_mmap_file(file, prot, flag);
	if (!ret) {
		down_write(&mm->mmap_sem);
		ret = do_mmap_pgoff(file, addr, len, prot, flag, pgoff,
				    &populate);
		up_write(&mm->mmap_sem);
		if (populate)
			mm_populate(ret, populate);
	}
	return ret;
}

unsigned long vm_mmap(struct file *file, unsigned long addr,
	unsigned long len, unsigned long prot,
	unsigned long flag, unsigned long offset)
{
	if (unlikely(offset + PAGE_ALIGN(len) < offset))
		return -EINVAL;
	if (unlikely(offset_in_page(offset)))
		return -EINVAL;

	return vm_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
}
EXPORT_SYMBOL(vm_mmap);

void kvfree(const void *addr)
{
	if (is_vmalloc_addr(addr))
		vfree(addr);
	else
		kfree(addr);
}
EXPORT_SYMBOL(kvfree);

static inline void *__page_rmapping(struct page *page)
{
	unsigned long mapping;

	mapping = (unsigned long)page->mapping;
	mapping &= ~PAGE_MAPPING_FLAGS;

	return (void *)mapping;
}

/* Neutral page->mapping pointer to address_space or anon_vma or other */
void *page_rmapping(struct page *page)
{
	page = compound_head(page);
	return __page_rmapping(page);
}

struct anon_vma *page_anon_vma(struct page *page)
{
	unsigned long mapping;

	page = compound_head(page);
	mapping = (unsigned long)page->mapping;
	if ((mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON)
		return NULL;
	return __page_rmapping(page);
}

struct address_space *page_mapping(struct page *page)
{
	struct address_space *mapping;

	page = compound_head(page);

	/* This happens if someone calls flush_dcache_page on slab page */
	if (unlikely(PageSlab(page)))
		return NULL;

	if (unlikely(PageSwapCache(page))) {
		swp_entry_t entry;

		entry.val = page_private(page);
		return swap_address_space(entry);
	}

	mapping = page->mapping;
	if ((unsigned long)mapping & PAGE_MAPPING_FLAGS)
		return NULL;
	return mapping;
}

/* Slow path of page_mapcount() for compound pages */
int __page_mapcount(struct page *page)
{
	int ret;

	ret = atomic_read(&page->_mapcount) + 1;
	page = compound_head(page);
	ret += atomic_read(compound_mapcount_ptr(page)) + 1;
	if (PageDoubleMap(page))
		ret--;
	return ret;
}
EXPORT_SYMBOL_GPL(__page_mapcount);

int overcommit_ratio_handler(struct ctl_table *table, int write,
			     void __user *buffer, size_t *lenp,
			     loff_t *ppos)
{
	int ret;

	ret = proc_dointvec(table, write, buffer, lenp, ppos);
	if (ret == 0 && write)
		sysctl_overcommit_kbytes = 0;
	return ret;
}

int overcommit_kbytes_handler(struct ctl_table *table, int write,
			     void __user *buffer, size_t *lenp,
			     loff_t *ppos)
{
	int ret;

	ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
	if (ret == 0 && write)
		sysctl_overcommit_ratio = 0;
	return ret;
}

/*
 * Committed memory limit enforced when OVERCOMMIT_NEVER policy is used
 */
unsigned long vm_commit_limit(void)
{
	unsigned long allowed;

	if (sysctl_overcommit_kbytes)
		allowed = sysctl_overcommit_kbytes >> (PAGE_SHIFT - 10);
	else
		allowed = ((totalram_pages - hugetlb_total_pages())
			   * sysctl_overcommit_ratio / 100);
	allowed += total_swap_pages;

	return allowed;
}

/**
 * get_cmdline() - copy the cmdline value to a buffer.
 * @task:     the task whose cmdline value to copy.
 * @buffer:   the buffer to copy to.
 * @buflen:   the length of the buffer. Larger cmdline values are truncated
 *            to this length.
 * Returns the size of the cmdline field copied. Note that the copy does
 * not guarantee an ending NULL byte.
 */
int get_cmdline(struct task_struct *task, char *buffer, int buflen)
{
	int res = 0;
	unsigned int len;
	struct mm_struct *mm = get_task_mm(task);
	unsigned long arg_start, arg_end, env_start, env_end;
	if (!mm)
		goto out;
	if (!mm->arg_end)
		goto out_mm;	/* Shh! No looking before we're done */

	down_read(&mm->mmap_sem);
	arg_start = mm->arg_start;
	arg_end = mm->arg_end;
	env_start = mm->env_start;
	env_end = mm->env_end;
	up_read(&mm->mmap_sem);

	len = arg_end - arg_start;

	if (len > buflen)
		len = buflen;

	res = access_process_vm(task, arg_start, buffer, len, 0);

	/*
	 * If the nul at the end of args has been overwritten, then
	 * assume application is using setproctitle(3).
	 */
	if (res > 0 && buffer[res-1] != '\0' && len < buflen) {
		len = strnlen(buffer, res);
		if (len < res) {
			res = len;
		} else {
			len = env_end - env_start;
			if (len > buflen - res)
				len = buflen - res;
			res += access_process_vm(task, env_start,
						 buffer+res, len, 0);
			res = strnlen(buffer, res);
		}
	}
out_mm:
	mmput(mm);
out:
	return res;
}
Commit	Line	Data
16d69265	1	#include <linux/mm.h>
30992c97 MM	2	#include <linux/slab.h>
30992c97 MM	3	#include <linux/string.h>
3b32123d	4	#include <linux/compiler.h>
b95f1b31	5	#include <linux/export.h>
96840aa0	6	#include <linux/err.h>
3b8f14b4	7	#include <linux/sched.h>
eb36c587	8	#include <linux/security.h>
9800339b	9	#include <linux/swap.h>
33806f06	10	#include <linux/swapops.h>
00619bcc JM	11	#include <linux/mman.h>
00619bcc JM	12	#include <linux/hugetlb.h>
39f1f78d	13	#include <linux/vmalloc.h>
00619bcc	14
a4bb1e43	15	#include <asm/sections.h>
96840aa0	16	#include <asm/uaccess.h>
30992c97	17
6038def0 NK	18	#include "internal.h"
6038def0 NK	19
a4bb1e43 AH	20	static inline int is_kernel_rodata(unsigned long addr)
	21	{
	22	return addr >= (unsigned long)__start_rodata &&
	23	addr < (unsigned long)__end_rodata;
	24	}
	25
	26	/**
	27	* kfree_const - conditionally free memory
	28	* @x: pointer to the memory
	29	*
	30	* Function calls kfree only if @x is not in .rodata section.
	31	*/
	32	void kfree_const(const void *x)
	33	{
	34	if (!is_kernel_rodata((unsigned long)x))
	35	kfree(x);
	36	}
	37	EXPORT_SYMBOL(kfree_const);
	38
30992c97	39	/**
30992c97	40	* kstrdup - allocate space for and copy an existing string
30992c97 MM	41	* @s: the string to duplicate
	42	* @gfp: the GFP mask used in the kmalloc() call when allocating memory
	43	*/
	44	char kstrdup(const char s, gfp_t gfp)
	45	{
	46	size_t len;
	47	char *buf;
	48
	49	if (!s)
	50	return NULL;
	51
	52	len = strlen(s) + 1;
1d2c8eea	53	buf = kmalloc_track_caller(len, gfp);
30992c97 MM	54	if (buf)
	55	memcpy(buf, s, len);
	56	return buf;
	57	}
	58	EXPORT_SYMBOL(kstrdup);
96840aa0	59
a4bb1e43 AH	60	/**
	61	* kstrdup_const - conditionally duplicate an existing const string
	62	* @s: the string to duplicate
	63	* @gfp: the GFP mask used in the kmalloc() call when allocating memory
	64	*
	65	* Function returns source string if it is in .rodata section otherwise it
	66	* fallbacks to kstrdup.
	67	* Strings allocated by kstrdup_const should be freed by kfree_const.
	68	*/
	69	const char kstrdup_const(const char s, gfp_t gfp)
	70	{
	71	if (is_kernel_rodata((unsigned long)s))
	72	return s;
	73
	74	return kstrdup(s, gfp);
	75	}
	76	EXPORT_SYMBOL(kstrdup_const);
	77
1e66df3e JF	78	/**
	79	* kstrndup - allocate space for and copy an existing string
	80	* @s: the string to duplicate
	81	* @max: read at most @max chars from @s
	82	* @gfp: the GFP mask used in the kmalloc() call when allocating memory
	83	*/
	84	char kstrndup(const char s, size_t max, gfp_t gfp)
	85	{
	86	size_t len;
	87	char *buf;
	88
	89	if (!s)
	90	return NULL;
	91
	92	len = strnlen(s, max);
	93	buf = kmalloc_track_caller(len+1, gfp);
	94	if (buf) {
	95	memcpy(buf, s, len);
	96	buf[len] = '\0';
	97	}
	98	return buf;
	99	}
	100	EXPORT_SYMBOL(kstrndup);
	101
1a2f67b4 AD	102	/**
	103	* kmemdup - duplicate region of memory
	104	*
	105	* @src: memory region to duplicate
	106	* @len: memory region length
	107	* @gfp: GFP mask to use
	108	*/
	109	void kmemdup(const void src, size_t len, gfp_t gfp)
	110	{
	111	void *p;
	112
1d2c8eea	113	p = kmalloc_track_caller(len, gfp);
1a2f67b4 AD	114	if (p)
	115	memcpy(p, src, len);
	116	return p;
	117	}
	118	EXPORT_SYMBOL(kmemdup);
	119
610a77e0 LZ	120	/**
	121	* memdup_user - duplicate memory region from user space
	122	*
	123	* @src: source address in user space
	124	* @len: number of bytes to copy
	125	*
	126	* Returns an ERR_PTR() on failure.
	127	*/
	128	void memdup_user(const void __user src, size_t len)
	129	{
	130	void *p;
	131
	132	/*
	133	* Always use GFP_KERNEL, since copy_from_user() can sleep and
	134	* cause pagefault, which makes it pointless to use GFP_NOFS
	135	* or GFP_ATOMIC.
	136	*/
	137	p = kmalloc_track_caller(len, GFP_KERNEL);
	138	if (!p)
	139	return ERR_PTR(-ENOMEM);
	140
	141	if (copy_from_user(p, src, len)) {
	142	kfree(p);
	143	return ERR_PTR(-EFAULT);
	144	}
	145
	146	return p;
	147	}
	148	EXPORT_SYMBOL(memdup_user);
	149
96840aa0 DA	150	/*
96840aa0 DA	151	* strndup_user - duplicate an existing string from user space
96840aa0 DA	152	* @s: The string to duplicate
	153	* @n: Maximum number of bytes to copy, including the trailing NUL.
	154	*/
	155	char strndup_user(const char __user s, long n)
	156	{
	157	char *p;
	158	long length;
	159
	160	length = strnlen_user(s, n);
	161
	162	if (!length)
	163	return ERR_PTR(-EFAULT);
	164
	165	if (length > n)
	166	return ERR_PTR(-EINVAL);
	167
90d74045	168	p = memdup_user(s, length);
96840aa0	169
90d74045 JL	170	if (IS_ERR(p))
90d74045 JL	171	return p;
96840aa0 DA	172
	173	p[length - 1] = '\0';
	174
	175	return p;
	176	}
	177	EXPORT_SYMBOL(strndup_user);
16d69265	178
e9d408e1 AV	179	/**
	180	* memdup_user_nul - duplicate memory region from user space and NUL-terminate
	181	*
	182	* @src: source address in user space
	183	* @len: number of bytes to copy
	184	*
	185	* Returns an ERR_PTR() on failure.
	186	*/
	187	void memdup_user_nul(const void __user src, size_t len)
	188	{
	189	char *p;
	190
	191	/*
	192	* Always use GFP_KERNEL, since copy_from_user() can sleep and
	193	* cause pagefault, which makes it pointless to use GFP_NOFS
	194	* or GFP_ATOMIC.
	195	*/
	196	p = kmalloc_track_caller(len + 1, GFP_KERNEL);
	197	if (!p)
	198	return ERR_PTR(-ENOMEM);
	199
	200	if (copy_from_user(p, src, len)) {
	201	kfree(p);
	202	return ERR_PTR(-EFAULT);
	203	}
	204	p[len] = '\0';
	205
	206	return p;
	207	}
	208	EXPORT_SYMBOL(memdup_user_nul);
	209
6038def0 NK	210	void __vma_link_list(struct mm_struct mm, struct vm_area_struct vma,
	211	struct vm_area_struct prev, struct rb_node rb_parent)
	212	{
	213	struct vm_area_struct *next;
	214
	215	vma->vm_prev = prev;
	216	if (prev) {
	217	next = prev->vm_next;
	218	prev->vm_next = vma;
	219	} else {
	220	mm->mmap = vma;
	221	if (rb_parent)
	222	next = rb_entry(rb_parent,
	223	struct vm_area_struct, vm_rb);
	224	else
	225	next = NULL;
	226	}
	227	vma->vm_next = next;
	228	if (next)
	229	next->vm_prev = vma;
	230	}
	231
b7643757	232	/* Check if the vma is being used as a stack by this task */
65376df5	233	int vma_is_stack_for_task(struct vm_area_struct vma, struct task_struct t)
b7643757 SP	234	{
	235	return (vma->vm_start <= KSTK_ESP(t) && vma->vm_end >= KSTK_ESP(t));
	236	}
	237
efc1a3b1	238	#if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)
16d69265 AM	239	void arch_pick_mmap_layout(struct mm_struct *mm)
	240	{
	241	mm->mmap_base = TASK_UNMAPPED_BASE;
	242	mm->get_unmapped_area = arch_get_unmapped_area;
16d69265 AM	243	}
16d69265 AM	244	#endif
912985dc	245
45888a0c XG	246	/*
	247	* Like get_user_pages_fast() except its IRQ-safe in that it won't fall
	248	* back to the regular GUP.
25985edc	249	* If the architecture not support this function, simply return with no
45888a0c XG	250	* page pinned
45888a0c XG	251	*/
3b32123d	252	int __weak __get_user_pages_fast(unsigned long start,
45888a0c XG	253	int nr_pages, int write, struct page **pages)
	254	{
	255	return 0;
	256	}
	257	EXPORT_SYMBOL_GPL(__get_user_pages_fast);
	258
9de100d0 AG	259	/**
	260	* get_user_pages_fast() - pin user pages in memory
	261	* @start: starting user address
	262	* @nr_pages: number of pages from start to pin
	263	* @write: whether pages will be written to
	264	* @pages: array that receives pointers to the pages pinned.
	265	* Should be at least nr_pages long.
	266	*
9de100d0 AG	267	* Returns number of pages pinned. This may be fewer than the number
	268	* requested. If nr_pages is 0 or negative, returns 0. If no pages
	269	* were pinned, returns -errno.
d2bf6be8 NP	270	*
	271	* get_user_pages_fast provides equivalent functionality to get_user_pages,
	272	* operating on current and current->mm, with force=0 and vma=NULL. However
	273	* unlike get_user_pages, it must be called without mmap_sem held.
	274	*
	275	* get_user_pages_fast may take mmap_sem and page table locks, so no
	276	* assumptions can be made about lack of locking. get_user_pages_fast is to be
	277	* implemented in a way that is advantageous (vs get_user_pages()) when the
	278	* user memory area is already faulted in and present in ptes. However if the
	279	* pages have to be faulted in, it may turn out to be slightly slower so
	280	* callers need to carefully consider what to use. On many architectures,
	281	* get_user_pages_fast simply falls back to get_user_pages.
9de100d0	282	*/
3b32123d	283	int __weak get_user_pages_fast(unsigned long start,
912985dc RR	284	int nr_pages, int write, struct page **pages)
912985dc RR	285	{
cde70140	286	return get_user_pages_unlocked(start, nr_pages, write, 0, pages);
912985dc RR	287	}
912985dc RR	288	EXPORT_SYMBOL_GPL(get_user_pages_fast);
ca2b84cb	289
eb36c587 AV	290	unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr,
	291	unsigned long len, unsigned long prot,
	292	unsigned long flag, unsigned long pgoff)
	293	{
	294	unsigned long ret;
	295	struct mm_struct *mm = current->mm;
41badc15	296	unsigned long populate;
eb36c587 AV	297
	298	ret = security_mmap_file(file, prot, flag);
	299	if (!ret) {
	300	down_write(&mm->mmap_sem);
bebeb3d6 ML	301	ret = do_mmap_pgoff(file, addr, len, prot, flag, pgoff,
bebeb3d6 ML	302	&populate);
eb36c587	303	up_write(&mm->mmap_sem);
41badc15 ML	304	if (populate)
41badc15 ML	305	mm_populate(ret, populate);
eb36c587 AV	306	}
	307	return ret;
	308	}
	309
	310	unsigned long vm_mmap(struct file *file, unsigned long addr,
	311	unsigned long len, unsigned long prot,
	312	unsigned long flag, unsigned long offset)
	313	{
	314	if (unlikely(offset + PAGE_ALIGN(len) < offset))
	315	return -EINVAL;
ea53cde0	316	if (unlikely(offset_in_page(offset)))
eb36c587 AV	317	return -EINVAL;
	318
	319	return vm_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
	320	}
	321	EXPORT_SYMBOL(vm_mmap);
	322
39f1f78d AV	323	void kvfree(const void *addr)
	324	{
	325	if (is_vmalloc_addr(addr))
	326	vfree(addr);
	327	else
	328	kfree(addr);
	329	}
	330	EXPORT_SYMBOL(kvfree);
	331
e39155ea KS	332	static inline void __page_rmapping(struct page page)
	333	{
	334	unsigned long mapping;
	335
	336	mapping = (unsigned long)page->mapping;
	337	mapping &= ~PAGE_MAPPING_FLAGS;
	338
	339	return (void *)mapping;
	340	}
	341
	342	/* Neutral page->mapping pointer to address_space or anon_vma or other */
	343	void page_rmapping(struct page page)
	344	{
	345	page = compound_head(page);
	346	return __page_rmapping(page);
	347	}
	348
	349	struct anon_vma page_anon_vma(struct page page)
	350	{
	351	unsigned long mapping;
	352
	353	page = compound_head(page);
	354	mapping = (unsigned long)page->mapping;
	355	if ((mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON)
	356	return NULL;
	357	return __page_rmapping(page);
	358	}
	359
9800339b SL	360	struct address_space page_mapping(struct page page)
9800339b SL	361	{
1c290f64 KS	362	struct address_space *mapping;
	363
	364	page = compound_head(page);
9800339b	365
03e5ac2f MP	366	/* This happens if someone calls flush_dcache_page on slab page */
	367	if (unlikely(PageSlab(page)))
	368	return NULL;
	369
33806f06 SL	370	if (unlikely(PageSwapCache(page))) {
	371	swp_entry_t entry;
	372
	373	entry.val = page_private(page);
e39155ea KS	374	return swap_address_space(entry);
	375	}
	376
1c290f64 KS	377	mapping = page->mapping;
1c290f64 KS	378	if ((unsigned long)mapping & PAGE_MAPPING_FLAGS)
e39155ea	379	return NULL;
1c290f64	380	return mapping;
9800339b SL	381	}
9800339b SL	382
b20ce5e0 KS	383	/* Slow path of page_mapcount() for compound pages */
	384	int __page_mapcount(struct page *page)
	385	{
	386	int ret;
	387
	388	ret = atomic_read(&page->_mapcount) + 1;
	389	page = compound_head(page);
	390	ret += atomic_read(compound_mapcount_ptr(page)) + 1;
	391	if (PageDoubleMap(page))
	392	ret--;
	393	return ret;
	394	}
	395	EXPORT_SYMBOL_GPL(__page_mapcount);
	396
49f0ce5f JM	397	int overcommit_ratio_handler(struct ctl_table *table, int write,
	398	void __user buffer, size_t lenp,
	399	loff_t *ppos)
	400	{
	401	int ret;
	402
	403	ret = proc_dointvec(table, write, buffer, lenp, ppos);
	404	if (ret == 0 && write)
	405	sysctl_overcommit_kbytes = 0;
	406	return ret;
	407	}
	408
	409	int overcommit_kbytes_handler(struct ctl_table *table, int write,
	410	void __user buffer, size_t lenp,
	411	loff_t *ppos)
	412	{
	413	int ret;
	414
	415	ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
	416	if (ret == 0 && write)
	417	sysctl_overcommit_ratio = 0;
	418	return ret;
	419	}
	420
00619bcc JM	421	/*
	422	* Committed memory limit enforced when OVERCOMMIT_NEVER policy is used
	423	*/
	424	unsigned long vm_commit_limit(void)
	425	{
49f0ce5f JM	426	unsigned long allowed;
	427
	428	if (sysctl_overcommit_kbytes)
	429	allowed = sysctl_overcommit_kbytes >> (PAGE_SHIFT - 10);
	430	else
	431	allowed = ((totalram_pages - hugetlb_total_pages())
	432	* sysctl_overcommit_ratio / 100);
	433	allowed += total_swap_pages;
	434
	435	return allowed;
00619bcc JM	436	}
00619bcc JM	437
a9090253 WR	438	/**
	439	* get_cmdline() - copy the cmdline value to a buffer.
	440	* @task: the task whose cmdline value to copy.
	441	* @buffer: the buffer to copy to.
	442	* @buflen: the length of the buffer. Larger cmdline values are truncated
	443	* to this length.
	444	* Returns the size of the cmdline field copied. Note that the copy does
	445	* not guarantee an ending NULL byte.
	446	*/
	447	int get_cmdline(struct task_struct task, char buffer, int buflen)
	448	{
	449	int res = 0;
	450	unsigned int len;
	451	struct mm_struct *mm = get_task_mm(task);
a3b609ef	452	unsigned long arg_start, arg_end, env_start, env_end;
a9090253 WR	453	if (!mm)
	454	goto out;
	455	if (!mm->arg_end)
	456	goto out_mm; /* Shh! No looking before we're done */
	457
a3b609ef MG	458	down_read(&mm->mmap_sem);
	459	arg_start = mm->arg_start;
	460	arg_end = mm->arg_end;
	461	env_start = mm->env_start;
	462	env_end = mm->env_end;
	463	up_read(&mm->mmap_sem);
	464
	465	len = arg_end - arg_start;
a9090253 WR	466
	467	if (len > buflen)
	468	len = buflen;
	469
a3b609ef	470	res = access_process_vm(task, arg_start, buffer, len, 0);
a9090253 WR	471
	472	/*
	473	* If the nul at the end of args has been overwritten, then
	474	* assume application is using setproctitle(3).
	475	*/
	476	if (res > 0 && buffer[res-1] != '\0' && len < buflen) {
	477	len = strnlen(buffer, res);
	478	if (len < res) {
	479	res = len;
	480	} else {
a3b609ef	481	len = env_end - env_start;
a9090253 WR	482	if (len > buflen - res)
a9090253 WR	483	len = buflen - res;
a3b609ef	484	res += access_process_vm(task, env_start,
a9090253 WR	485	buffer+res, len, 0);
	486	res = strnlen(buffer, res);
	487	}
	488	}
	489	out_mm:
	490	mmput(mm);
	491	out:
	492	return res;
	493	}