linux-toradex.git/mm/nommu.c, branch v3.0.95

vm: add no-mmu vm_iomap_memory() stub

2013-08-20T15:21:01+00:00

commit 3c0b9de6d37a481673e81001c57ca0e410c72346 upstream.

I think we could just move the full vm_iomap_memory() function into
util.h or similar, but I didn't get any reply from anybody actually
using nommu even to this trivial patch, so I'm not going to touch it any
more than required.

Here's the fairly minimal stub to make the nommu case at least
potentially work.  It doesn't seem like anybody cares, though.

Signed-off-by: Linus Torvalds 
Cc: Guenter Roeck 
Signed-off-by: Greg Kroah-Hartman

mm: prevent mmap_cache race in find_vma()

2013-04-12T16:18:09+00:00

commit b6a9b7f6b1f21735a7456d534dc0e68e61359d2c upstream.

find_vma() can be called by multiple threads with read lock
held on mm->mmap_sem and any of them can update mm->mmap_cache.
Prevent compiler from re-fetching mm->mmap_cache, because other
readers could update it in the meantime:

               thread 1                             thread 2
                                        |
  find_vma()                            |  find_vma()
    struct vm_area_struct *vma = NULL;  |
    vma = mm->mmap_cache;               |
    if (!(vma && vma->vm_end > addr     |
        && vma->vm_start <= addr)) {    |
                                        |    mm->mmap_cache = vma;
    return vma;                         |
     ^^ compiler may optimize this      |
        local variable out and re-read  |
        mm->mmap_cache                  |

This issue can be reproduced with gcc-4.8.0-1 on s390x by running
mallocstress testcase from LTP, which triggers:

  kernel BUG at mm/rmap.c:1088!
    Call Trace:
     ([<000003d100c57000>] 0x3d100c57000)
      [<000000000023a1c0>] do_wp_page+0x2fc/0xa88
      [<000000000023baae>] handle_pte_fault+0x41a/0xac8
      [<000000000023d832>] handle_mm_fault+0x17a/0x268
      [<000000000060507a>] do_protection_exception+0x1e2/0x394
      [<0000000000603a04>] pgm_check_handler+0x138/0x13c
      [<000003fffcf1f07a>] 0x3fffcf1f07a
    Last Breaking-Event-Address:
      [<000000000024755e>] page_add_new_anon_rmap+0xc2/0x168

Thanks to Jakub Jelinek for his insight on gcc and helping to
track this down.

Signed-off-by: Jan Stancek 
Acked-by: David Rientjes 
Signed-off-by: Hugh Dickins 
Signed-off-by: Linus Torvalds 
[bwh: Backported to 3.2: adjust context, indentation]
Signed-off-by: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

NOMMU: Don't need to clear vm_mm when deleting a VMA

2012-03-12T17:32:56+00:00

commit b94cfaf6685d691dc3fab023cf32f65e9b7be09c upstream.

Don't clear vm_mm in a deleted VMA as it's unnecessary and might
conceivably break the filesystem or driver VMA close routine.

Reported-by: Al Viro 
Signed-off-by: David Howells 
Acked-by: Al Viro 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

NOMMU: Lock i_mmap_mutex for access to the VMA prio list

2012-03-01T00:33:36+00:00

commit 918e556ec214ed2f584e4cac56d7b29e4bb6bf27 upstream.

Lock i_mmap_mutex for access to the VMA prio list to prevent concurrent
access.  Currently, certain parts of the mmap handling are protected by
the region mutex, but not all.

Reported-by: Al Viro 
Signed-off-by: David Howells 
Acked-by: Al Viro 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

mm/nommu.c: fix remap_pfn_range()

2011-07-09T04:14:44+00:00

remap_pfn_range() means map physical address pfn<vm_start = pfn << PAGE_SHIFT which
is wrong acroding the original meaning of this function.  And some driver
developer using remap_pfn_range() with correct parameter will get
unexpected result because vm_start is changed.  It should be implementd
like addr = pfn << PAGE_SHIFT but which is meanless on nommu arch, this
patch just make it simply return.

Parameter name and setting of vma->vm_flags also be fixed.

Signed-off-by: Bob Liu 
Cc: Geert Uytterhoeven 
Cc: David Howells 
Acked-by: Greg Ungerer 
Cc: Mike Frysinger 
Cc: Bob Liu 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

nommu: add page alignment to mmap

2011-05-25T15:39:38+00:00

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 
Cc: David Howells 
Cc: Paul Mundt 
Cc: Greg Ungerer 
Cc: Geert Uytterhoeven 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: nommu: fix a compile warning in do_mmap_pgoff()

2011-05-25T15:39:07+00:00

Because 'ret' is declared as int, not unsigned long, no need to cast the
error contants into unsigned long.  If you compile this code on a 64-bit
machine somehow, you'll see following warning:

    CC      mm/nommu.o
  mm/nommu.c: In function `do_mmap_pgoff':
  mm/nommu.c:1411: warning: overflow in implicit constant conversion

Signed-off-by: Namhyung Kim 
Acked-by: Greg Ungerer 
Cc: David Howells 
Cc: Paul Mundt 
Cc: Geert Uytterhoeven 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: nommu: fix a potential memory leak in do_mmap_private()

2011-05-25T15:39:06+00:00

If f_op->read() fails and sysctl_nr_trim_pages > 1, there could be a
memory leak between @region->vm_end and @region->vm_top.

Signed-off-by: Namhyung Kim 
Acked-by: Greg Ungerer 
Cc: David Howells 
Cc: Paul Mundt 
Cc: Geert Uytterhoeven 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: nommu: check the vma list when unmapping file-mapped vma

2011-05-25T15:39:06+00:00

Now we have the sorted vma list, use it in do_munmap() to check that we
have an exact match.

Signed-off-by: Namhyung Kim 
Acked-by: Greg Ungerer 
Cc: David Howells 
Cc: Paul Mundt 
Cc: Geert Uytterhoeven 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: nommu: find vma using the sorted vma list

2011-05-25T15:39:06+00:00

Now we have the sorted vma list, use it in the find_vma[_exact]() rather
than doing linear search on the rb-tree.

Signed-off-by: Namhyung Kim 
Acked-by: Greg Ungerer 
Cc: David Howells 
Cc: Paul Mundt 
Cc: Geert Uytterhoeven 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds