nommu: add page alignment to mmap
Currently on nommu arch mmap(),mremap() and munmap() doesn't do
page_align() which isn't consist with mmu arch and cause some issues.
First, some drivers' mmap() function depends on vma->vm_end - vma->start
is page aligned which is true on mmu arch but not on nommu. eg: uvc
camera driver.
Second munmap() may return -EINVAL[split file] error in cases when end is
not page aligned(passed into from userspace) but vma->vm_end is aligned
dure to split or driver's mmap() ops.
Add page alignment to fix those issues.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Greg Ungerer <gerg@snapgear.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/nommu.c b/mm/nommu.c
index 92e1a47d..1fd0c51 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1124,7 +1124,7 @@
unsigned long capabilities)
{
struct page *pages;
- unsigned long total, point, n, rlen;
+ unsigned long total, point, n;
void *base;
int ret, order;
@@ -1148,13 +1148,12 @@
* make a private copy of the data and map that instead */
}
- rlen = PAGE_ALIGN(len);
/* allocate some memory to hold the mapping
* - note that this may not return a page-aligned address if the object
* we're allocating is smaller than a page
*/
- order = get_order(rlen);
+ order = get_order(len);
kdebug("alloc order %d for %lx", order, len);
pages = alloc_pages(GFP_KERNEL, order);
@@ -1164,7 +1163,7 @@
total = 1 << order;
atomic_long_add(total, &mmap_pages_allocated);
- point = rlen >> PAGE_SHIFT;
+ point = len >> PAGE_SHIFT;
/* we allocated a power-of-2 sized page set, so we may want to trim off
* the excess */
@@ -1186,7 +1185,7 @@
base = page_address(pages);
region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
region->vm_start = (unsigned long) base;
- region->vm_end = region->vm_start + rlen;
+ region->vm_end = region->vm_start + len;
region->vm_top = region->vm_start + (total << PAGE_SHIFT);
vma->vm_start = region->vm_start;
@@ -1202,15 +1201,15 @@
old_fs = get_fs();
set_fs(KERNEL_DS);
- ret = vma->vm_file->f_op->read(vma->vm_file, base, rlen, &fpos);
+ ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
set_fs(old_fs);
if (ret < 0)
goto error_free;
/* clear the last little bit */
- if (ret < rlen)
- memset(base + ret, 0, rlen - ret);
+ if (ret < len)
+ memset(base + ret, 0, len - ret);
}
@@ -1259,6 +1258,7 @@
/* we ignore the address hint */
addr = 0;
+ len = PAGE_ALIGN(len);
/* we've determined that we can make the mapping, now translate what we
* now know into VMA flags */
@@ -1635,14 +1635,17 @@
int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
{
struct vm_area_struct *vma;
- unsigned long end = start + len;
+ unsigned long end;
int ret;
kenter(",%lx,%zx", start, len);
+ len = PAGE_ALIGN(len);
if (len == 0)
return -EINVAL;
+ end = start + len;
+
/* find the first potentially overlapping VMA */
vma = find_vma(mm, start);
if (!vma) {
@@ -1762,6 +1765,8 @@
struct vm_area_struct *vma;
/* insanity checks first */
+ old_len = PAGE_ALIGN(old_len);
+ new_len = PAGE_ALIGN(new_len);
if (old_len == 0 || new_len == 0)
return (unsigned long) -EINVAL;