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Commit 83342314 authored by Nick Piggin's avatar Nick Piggin Committed by Linus Torvalds
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[PATCH] mm: introduce remap_vmalloc_range() 



Add remap_vmalloc_range, vmalloc_user, and vmalloc_32_user so that drivers
can have a nice interface for remapping vmalloc memory.

Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 762834e8

include/linux/vmalloc.h

+8 −0
Original line number Diff line number Diff line
@@ -4,10 +4,13 @@ 
#include <linux/spinlock.h>

#include <asm/page.h>		/* pgprot_t */



struct vm_area_struct;



/* bits in vm_struct->flags */

#define VM_IOREMAP	0x00000001	/* ioremap() and friends */

#define VM_ALLOC	0x00000002	/* vmalloc() */

#define VM_MAP		0x00000004	/* vmap()ed pages */

#define VM_USERMAP	0x00000008	/* suitable for remap_vmalloc_range */

/* bits [20..32] reserved for arch specific ioremap internals */



/*
@@ -32,9 +35,11 @@ struct vm_struct { 
 *	Highlevel APIs for driver use

 */

extern void *vmalloc(unsigned long size);

extern void *vmalloc_user(unsigned long size);

extern void *vmalloc_node(unsigned long size, int node);

extern void *vmalloc_exec(unsigned long size);

extern void *vmalloc_32(unsigned long size);

extern void *vmalloc_32_user(unsigned long size);

extern void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot);

extern void *__vmalloc_area(struct vm_struct *area, gfp_t gfp_mask,

				pgprot_t prot);
@@ -46,6 +51,9 @@ extern void *vmap(struct page **pages, unsigned int count, 
			unsigned long flags, pgprot_t prot);

extern void vunmap(void *addr);



extern int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,

							unsigned long pgoff);

 

/*

 *	Lowlevel-APIs (not for driver use!)

 */

mm/vmalloc.c

+120 −2
Original line number Diff line number Diff line
@@ -256,6 +256,19 @@ struct vm_struct *get_vm_area_node(unsigned long size, unsigned long flags, int 
	return __get_vm_area_node(size, flags, VMALLOC_START, VMALLOC_END, node);

}



/* Caller must hold vmlist_lock */

static struct vm_struct *__find_vm_area(void *addr)

{

	struct vm_struct *tmp;



	for (tmp = vmlist; tmp != NULL; tmp = tmp->next) {

		 if (tmp->addr == addr)

			break;

	}



	return tmp;

}



/* Caller must hold vmlist_lock */

struct vm_struct *__remove_vm_area(void *addr)

{
@@ -502,6 +515,28 @@ void *vmalloc(unsigned long size) 
}

EXPORT_SYMBOL(vmalloc);



/**

 *	vmalloc_user  -  allocate virtually contiguous memory which has

 *			   been zeroed so it can be mapped to userspace without

 *			   leaking data.

 *

 *	@size:		allocation size

 */

void *vmalloc_user(unsigned long size)

{

	struct vm_struct *area;

	void *ret;



	ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL);

	write_lock(&vmlist_lock);

	area = __find_vm_area(ret);

	area->flags |= VM_USERMAP;

	write_unlock(&vmlist_lock);



	return ret;

}

EXPORT_SYMBOL(vmalloc_user);



/**

 *	vmalloc_node  -  allocate memory on a specific node

 *
@@ -556,6 +591,28 @@ void *vmalloc_32(unsigned long size) 
}

EXPORT_SYMBOL(vmalloc_32);



/**

 *	vmalloc_32_user  -  allocate virtually contiguous memory (32bit

 *			      addressable) which is zeroed so it can be

 *			      mapped to userspace without leaking data.

 *

 *	@size:		allocation size

 */

void *vmalloc_32_user(unsigned long size)

{

	struct vm_struct *area;

	void *ret;



	ret = __vmalloc(size, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL);

	write_lock(&vmlist_lock);

	area = __find_vm_area(ret);

	area->flags |= VM_USERMAP;

	write_unlock(&vmlist_lock);



	return ret;

}

EXPORT_SYMBOL(vmalloc_32_user);



long vread(char *buf, char *addr, unsigned long count)

{

	struct vm_struct *tmp;
@@ -630,3 +687,64 @@ finished: 
	read_unlock(&vmlist_lock);

	return buf - buf_start;

}



/**

 *	remap_vmalloc_range  -  map vmalloc pages to userspace

 *

 *	@vma:		vma to cover (map full range of vma)

 *	@addr:		vmalloc memory

 *	@pgoff:		number of pages into addr before first page to map

 *	@returns:	0 for success, -Exxx on failure

 *

 *	This function checks that addr is a valid vmalloc'ed area, and

 *	that it is big enough to cover the vma. Will return failure if

 *	that criteria isn't met.

 *

 *	Similar to remap_pfn_range (see mm/memory.c)

 */

int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,

						unsigned long pgoff)

{

	struct vm_struct *area;

	unsigned long uaddr = vma->vm_start;

	unsigned long usize = vma->vm_end - vma->vm_start;

	int ret;



	if ((PAGE_SIZE-1) & (unsigned long)addr)

		return -EINVAL;



	read_lock(&vmlist_lock);

	area = __find_vm_area(addr);

	if (!area)

		goto out_einval_locked;



	if (!(area->flags & VM_USERMAP))

		goto out_einval_locked;



	if (usize + (pgoff << PAGE_SHIFT) > area->size - PAGE_SIZE)

		goto out_einval_locked;

	read_unlock(&vmlist_lock);



	addr += pgoff << PAGE_SHIFT;

	do {

		struct page *page = vmalloc_to_page(addr);

		ret = vm_insert_page(vma, uaddr, page);

		if (ret)

			return ret;



		uaddr += PAGE_SIZE;

		addr += PAGE_SIZE;

		usize -= PAGE_SIZE;

	} while (usize > 0);



	/* Prevent "things" like memory migration? VM_flags need a cleanup... */

	vma->vm_flags |= VM_RESERVED;



	return ret;



out_einval_locked:

	read_unlock(&vmlist_lock);

	return -EINVAL;

}

EXPORT_SYMBOL(remap_vmalloc_range);