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[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: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
David Howells 2006-09-27 01:50:20 -07:00 committed by Linus Torvalds
parent dbf8685c8e
commit 3034097a50
1 changed files with 72 additions and 32 deletions
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104
mm/nommu.c
View File

@ -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)
{