Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 3034097a authored by David Howells's avatar David Howells Committed by Linus Torvalds
Browse files

[PATCH] NOMMU: Order the per-mm_struct VMA list 



Order the per-mm_struct VMA list by address so that searching it can be cut
short when the appropriate address has been exceeded.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent dbf8685c

mm/nommu.c

+72 −32
Original line number Diff line number Diff line
@@ -310,6 +310,48 @@ static void show_process_blocks(void) 
}

#endif /* DEBUG */



/*

 * add a VMA into a process's mm_struct in the appropriate place in the list

 * - should be called with mm->mmap_sem held writelocked

 */

static void add_vma_to_mm(struct mm_struct *mm, struct vm_list_struct *vml)

{

	struct vm_list_struct **ppv;



	for (ppv = &current->mm->context.vmlist; *ppv; ppv = &(*ppv)->next)

		if ((*ppv)->vma->vm_start > vml->vma->vm_start)

			break;



	vml->next = *ppv;

	*ppv = vml;

}



/*

 * look up the first VMA in which addr resides, NULL if none

 * - should be called with mm->mmap_sem at least held readlocked

 */

struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)

{

	struct vm_list_struct *loop, *vml;



	/* search the vm_start ordered list */

	vml = NULL;

	for (loop = mm->context.vmlist; loop; loop = loop->next) {

		if (loop->vma->vm_start > addr)

			break;

		vml = loop;

	}



	if (vml && vml->vma->vm_end > addr)

		return vml->vma;



	return NULL;

}

EXPORT_SYMBOL(find_vma);



/*

 * find a VMA in the global tree

 */

static inline struct vm_area_struct *find_nommu_vma(unsigned long start)

{

	struct vm_area_struct *vma;
@@ -329,6 +371,9 @@ static inline struct vm_area_struct *find_nommu_vma(unsigned long start) 
	return NULL;

}



/*

 * add a VMA in the global tree

 */

static void add_nommu_vma(struct vm_area_struct *vma)

{

	struct vm_area_struct *pvma;
@@ -375,6 +420,9 @@ static void add_nommu_vma(struct vm_area_struct *vma) 
	rb_insert_color(&vma->vm_rb, &nommu_vma_tree);

}



/*

 * delete a VMA from the global list

 */

static void delete_nommu_vma(struct vm_area_struct *vma)

{

	struct address_space *mapping;
@@ -852,8 +900,7 @@ unsigned long do_mmap_pgoff(struct file *file, 
	realalloc += kobjsize(vml);

	askedalloc += sizeof(*vml);



	vml->next = current->mm->context.vmlist;

	current->mm->context.vmlist = vml;

	add_vma_to_mm(current->mm, vml);



	up_write(&nommu_vma_sem);
@@ -932,6 +979,11 @@ static void put_vma(struct vm_area_struct *vma) 
	}

}



/*

 * release a mapping

 * - under NOMMU conditions the parameters must match exactly to the mapping to

 *   be removed

 */

int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len)

{

	struct vm_list_struct *vml, **parent;
@@ -941,10 +993,13 @@ int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len) 
	printk("do_munmap:\n");

#endif



	for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next)

	for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next) {

		if ((*parent)->vma->vm_start > addr)

			break;

		if ((*parent)->vma->vm_start == addr &&

		    ((len == 0) || ((*parent)->vma->vm_end == end)))

			goto found;

	}



	printk("munmap of non-mmaped memory by process %d (%s): %p\n",

	       current->pid, current->comm, (void *) addr);
@@ -970,7 +1025,20 @@ int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len) 
	return 0;

}



/* Release all mmaps. */

asmlinkage long sys_munmap(unsigned long addr, size_t len)

{

	int ret;

	struct mm_struct *mm = current->mm;



	down_write(&mm->mmap_sem);

	ret = do_munmap(mm, addr, len);

	up_write(&mm->mmap_sem);

	return ret;

}



/*

 * Release all mappings

 */

void exit_mmap(struct mm_struct * mm)

{

	struct vm_list_struct *tmp;
@@ -997,17 +1065,6 @@ void exit_mmap(struct mm_struct * mm) 
	}

}



asmlinkage long sys_munmap(unsigned long addr, size_t len)

{

	int ret;

	struct mm_struct *mm = current->mm;



	down_write(&mm->mmap_sem);

	ret = do_munmap(mm, addr, len);

	up_write(&mm->mmap_sem);

	return ret;

}



unsigned long do_brk(unsigned long addr, unsigned long len)

{

	return -ENOMEM;
@@ -1061,23 +1118,6 @@ unsigned long do_mremap(unsigned long addr, 
	return vml->vma->vm_start;

}



/*

 * Look up the first VMA which satisfies  addr < vm_end,  NULL if none

 * - should be called with mm->mmap_sem at least readlocked

 */

struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)

{

	struct vm_list_struct *vml;



	for (vml = mm->context.vmlist; vml; vml = vml->next)

		if (addr >= vml->vma->vm_start && addr < vml->vma->vm_end)

			return vml->vma;



	return NULL;

}



EXPORT_SYMBOL(find_vma);



struct page *follow_page(struct vm_area_struct *vma, unsigned long address,

			unsigned int foll_flags)

{