Commit 50fd2f29 authored by Al Viro's avatar Al Viro
Browse files

new primitive: vmemdup_user() 



similar to memdup_user(), but does *not* guarantee that result will
be physically contiguous; use only in cases where that's not a requirement
and free it with kvfree().

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 6c2c97a2

include/linux/string.h

+1 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 


extern char *strndup_user(const char __user *, long);

extern void *memdup_user(const void __user *, size_t);

extern void *vmemdup_user(const void __user *, size_t);

extern void *memdup_user_nul(const void __user *, size_t);



/*

mm/util.c

+28 −1
Original line number Diff line number Diff line
@@ -150,7 +150,8 @@ EXPORT_SYMBOL(kmemdup_nul); 
 * @src: source address in user space

 * @len: number of bytes to copy

 *

 * Returns an ERR_PTR() on failure.

 * Returns an ERR_PTR() on failure.  Result is physically

 * contiguous, to be freed by kfree().

 */

void *memdup_user(const void __user *src, size_t len)

{
@@ -169,6 +170,32 @@ void *memdup_user(const void __user *src, size_t len) 
}

EXPORT_SYMBOL(memdup_user);



/**

 * vmemdup_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.  Result may be not

 * physically contiguous.  Use kvfree() to free.

 */

void *vmemdup_user(const void __user *src, size_t len)

{

	void *p;



	p = kvmalloc(len, GFP_USER);

	if (!p)

		return ERR_PTR(-ENOMEM);



	if (copy_from_user(p, src, len)) {

		kvfree(p);

		return ERR_PTR(-EFAULT);

	}



	return p;

}

EXPORT_SYMBOL(vmemdup_user);



/*

 * strndup_user - duplicate an existing string from user space

 * @s: The string to duplicate