int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start,
int len, int write, int force, struct page **pages, struct vm_area_struct **vmas)
{
int i = 0;
do {
struct vm_area_struct * vma;
vma = find_extend_vma(mm, start);
if ( !vma ||
(!force &&
((write && (!(vma->vm_flags & VM_WRITE))) ||
(!write && (!(vma->vm_flags & VM_READ))) ) )) {
if (i) return i;
return -EFAULT;
}
spin_lock(&mm->page_table_lock);
do {
struct page *map;
while (!(map = follow_page(mm, start, write))) {
spin_unlock(&mm->page_table_lock);
switch (handle_mm_fault(mm, vma, start, write)) {
case 1:
tsk->min_flt++;
break;
case 2:
tsk->maj_flt++;
break;
case 0:
if (i) return i;
return -EFAULT;
default:
if (i) return i;
return -ENOMEM;
}
spin_lock(&mm->page_table_lock);
}
if (pages) {
pages[i] = get_page_map(map);
/* FIXME: call the correct function,
* depending on the type of the found page
*/
if (pages[i])
page_cache_get(pages[i]);
}
if (vmas)
vmas[i] = vma;
i++;
start += PAGE_SIZE;
len--;
} while(len && start < vma->vm_end);
spin_unlock(&mm->page_table_lock);
} while(len);
return i;
}
int map_user_kiobuf(int rw, struct kiobuf *iobuf, unsigned long va, size_t len)
{
unsigned long ptr, end;
int err;
struct mm_struct * mm;
struct vm_area_struct * vma = 0;
struct page * map;
int i;
int datain = (rw == READ);
/* Make sure the iobuf is not already mapped somewhere. */
if (iobuf->nr_pages)
return -EINVAL;
mm = current->mm;
dprintk ("map_user_kiobuf: begin\n");
ptr = va & PAGE_MASK;
end = (va + len + PAGE_SIZE - 1) & PAGE_MASK;
err = expand_kiobuf(iobuf, (end - ptr) >> PAGE_SHIFT);
if (err)
return err;
down(&mm->mmap_sem);
err = -EFAULT;
iobuf->locked = 0;
iobuf->offset = va & ~PAGE_MASK;
iobuf->length = len;
i = 0;
/*
* First of all, try to fault in all of the necessary pages
*/
while (ptr < end) {
if (!vma || ptr >= vma->vm_end) {
vma = find_vma(current->mm, ptr);
if (!vma)
goto out_unlock;
if (vma->vm_start > ptr) {
if (!(vma->vm_flags & VM_GROWSDOWN))
goto out_unlock;
if (expand_stack(vma, ptr))
goto out_unlock;
}
if (((datain) && (!(vma->vm_flags & VM_WRITE))) ||
(!(vma->vm_flags & VM_READ))) {
err = -EACCES;
goto out_unlock;
}
}
if (handle_mm_fault(current->mm, vma, ptr, datain) <= 0)
goto out_unlock;
spin_lock(&mm->page_table_lock);
map = follow_page(ptr);
if (!map) {
spin_unlock(&mm->page_table_lock);
dprintk (KERN_ERR "Missing page in map_user_kiobuf\n");
goto out_unlock;
}
map = get_page_map(map);
if (map)
atomic_inc(&map->count);
else
printk (KERN_INFO "Mapped page missing [%d]\n", i);
spin_unlock(&mm->page_table_lock);
iobuf->maplist[i] = map;
iobuf->nr_pages = ++i;
ptr += PAGE_SIZE;
}
up(&mm->mmap_sem);
dprintk ("map_user_kiobuf: end OK\n");
return 0;
out_unlock:
up(&mm->mmap_sem);
unmap_kiobuf(iobuf);
dprintk ("map_user_kiobuf: end %d\n", err);
return err;
}
/*
* Please read Documentation/cachetlb.txt before using this function,
* accessing foreign memory spaces can cause cache coherency problems.
*
* Accessing a VM_IO area is even more dangerous, therefore the function
* fails if pages is != NULL and a VM_IO area is found.
*/
int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start,
int len, int write, int force, struct page **pages, struct vm_area_struct **vmas)
{
int i;
unsigned int flags;
/*
* Require read or write permissions.
* If 'force' is set, we only require the "MAY" flags.
*/
flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
i = 0;
do {
struct vm_area_struct * vma;
vma = find_extend_vma(mm, start);
if ( !vma || (pages && vma->vm_flags & VM_IO) || !(flags & vma->vm_flags) )
return i ? : -EFAULT;
spin_lock(&mm->page_table_lock);
do {
struct page *map;
while (!(map = follow_page(mm, start, write))) {
spin_unlock(&mm->page_table_lock);
switch (handle_mm_fault(mm, vma, start, write)) {
case 1:
tsk->min_flt++;
break;
case 2:
tsk->maj_flt++;
break;
case 0:
if (i) return i;
return -EFAULT;
default:
if (i) return i;
return -ENOMEM;
}
spin_lock(&mm->page_table_lock);
}
if (pages) {
pages[i] = get_page_map(map);
/* FIXME: call the correct function,
* depending on the type of the found page
*/
if (!pages[i])
goto bad_page;
page_cache_get(pages[i]);
}
if (vmas)
vmas[i] = vma;
i++;
start += PAGE_SIZE;
len--;
} while(len && start < vma->vm_end);
spin_unlock(&mm->page_table_lock);
} while(len);
out:
return i;
/*
* We found an invalid page in the VMA. Release all we have
* so far and fail.
*/
bad_page:
spin_unlock(&mm->page_table_lock);
while (i--)
page_cache_release(pages[i]);
i = -EFAULT;
goto out;
}
