The patch titled
nommu: add page alignment to mmap
has been added to the -mm tree. Its filename is
nommu-add-page-alignment-to-mmap.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: nommu: add page alignment to mmap
From: Bob Liu <lliubbo@xxxxxxxxx>
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.
Signed-off-by: Bob Liu <lliubbo@xxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: Paul Mundt <lethal@xxxxxxxxxxxx>
Cc: Greg Ungerer <gerg@xxxxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/nommu.c | 24 ++++++++++++++----------
1 file changed, 14 insertions(+), 10 deletions(-)
diff -puN mm/nommu.c~nommu-add-page-alignment-to-mmap mm/nommu.c
--- a/mm/nommu.c~nommu-add-page-alignment-to-mmap
+++ a/mm/nommu.c
@@ -1124,7 +1124,7 @@ static int do_mmap_private(struct vm_are
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 @@ static int do_mmap_private(struct vm_are
* 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 @@ static int do_mmap_private(struct vm_are
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 @@ static int do_mmap_private(struct vm_are
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 @@ static int do_mmap_private(struct vm_are
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);
}
@@ -1260,6 +1259,7 @@ unsigned long do_mmap_pgoff(struct file
/* 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 */
@@ -1636,14 +1636,16 @@ static int shrink_vma(struct mm_struct *
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);
- if (len == 0)
+ if ((len = PAGE_ALIGN(len)) == 0)
return -EINVAL;
+ end = start + len;
+
/* find the first potentially overlapping VMA */
vma = find_vma(mm, start);
if (!vma) {
@@ -1763,6 +1765,8 @@ unsigned long do_mremap(unsigned long ad
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;
_
Patches currently in -mm which might be from lliubbo@xxxxxxxxx are
nommu-add-page-alignment-to-mmap.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
