mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 02:39:48 +00:00
![Rusty Russell](/assets/img/avatar_default.png)
Out of line get_user_pages_fast fallback implementation, make it a weak symbol, get rid of CONFIG_HAVE_GET_USER_PAGES_FAST. Export the symbol to modules so lguest can use it. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
188 lines
3.9 KiB
C
188 lines
3.9 KiB
C
#include <linux/mm.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/string.h>
|
|
#include <linux/module.h>
|
|
#include <linux/err.h>
|
|
#include <linux/sched.h>
|
|
#include <asm/uaccess.h>
|
|
|
|
/**
|
|
* 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);
|
|
|
|
/**
|
|
* 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);
|
|
|
|
/**
|
|
* __krealloc - like krealloc() but don't free @p.
|
|
* @p: object to reallocate memory for.
|
|
* @new_size: how many bytes of memory are required.
|
|
* @flags: the type of memory to allocate.
|
|
*
|
|
* This function is like krealloc() except it never frees the originally
|
|
* allocated buffer. Use this if you don't want to free the buffer immediately
|
|
* like, for example, with RCU.
|
|
*/
|
|
void *__krealloc(const void *p, size_t new_size, gfp_t flags)
|
|
{
|
|
void *ret;
|
|
size_t ks = 0;
|
|
|
|
if (unlikely(!new_size))
|
|
return ZERO_SIZE_PTR;
|
|
|
|
if (p)
|
|
ks = ksize(p);
|
|
|
|
if (ks >= new_size)
|
|
return (void *)p;
|
|
|
|
ret = kmalloc_track_caller(new_size, flags);
|
|
if (ret && p)
|
|
memcpy(ret, p, ks);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(__krealloc);
|
|
|
|
/**
|
|
* krealloc - reallocate memory. The contents will remain unchanged.
|
|
* @p: object to reallocate memory for.
|
|
* @new_size: how many bytes of memory are required.
|
|
* @flags: the type of memory to allocate.
|
|
*
|
|
* The contents of the object pointed to are preserved up to the
|
|
* lesser of the new and old sizes. If @p is %NULL, krealloc()
|
|
* behaves exactly like kmalloc(). If @size is 0 and @p is not a
|
|
* %NULL pointer, the object pointed to is freed.
|
|
*/
|
|
void *krealloc(const void *p, size_t new_size, gfp_t flags)
|
|
{
|
|
void *ret;
|
|
|
|
if (unlikely(!new_size)) {
|
|
kfree(p);
|
|
return ZERO_SIZE_PTR;
|
|
}
|
|
|
|
ret = __krealloc(p, new_size, flags);
|
|
if (ret && p != ret)
|
|
kfree(p);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(krealloc);
|
|
|
|
/*
|
|
* 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 = kmalloc(length, GFP_KERNEL);
|
|
|
|
if (!p)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
if (copy_from_user(p, s, length)) {
|
|
kfree(p);
|
|
return ERR_PTR(-EFAULT);
|
|
}
|
|
|
|
p[length - 1] = '\0';
|
|
|
|
return p;
|
|
}
|
|
EXPORT_SYMBOL(strndup_user);
|
|
|
|
#ifndef 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;
|
|
mm->unmap_area = arch_unmap_area;
|
|
}
|
|
#endif
|
|
|
|
int __attribute__((weak)) get_user_pages_fast(unsigned long start,
|
|
int nr_pages, int write, struct page **pages)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
int ret;
|
|
|
|
down_read(&mm->mmap_sem);
|
|
ret = get_user_pages(current, mm, start, nr_pages,
|
|
write, 0, pages, NULL);
|
|
up_read(&mm->mmap_sem);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(get_user_pages_fast);
|