Re: [PATCH] omap_vout: find_vma() needs ->mmap_sem held

[Laurent Pinchart]

On Sunday 16 December 2012 20:04:46 Al Viro wrote:
> On Sun, Dec 16, 2012 at 09:01:10PM +0100, Paul Bolle wrote:
> > > + vma = find_vma(mm, virtp);
> > > 
> > >   } else if (vma && (vma->vm_flags & VM_IO) && vma->vm_pgoff) {
> > 
> > Shouldn't that line become
> > 
> >     if (vma && (vma->vm_flags & VM_IO) && vma->vm_pgoff) {
> > 
> > so that this actually compiles?
> 
> *Do'h*
> 
> Yes, it should.  Mea culpa...
> 
> Signed-off-by: Al Viro <v...@zeniv.linux.org.uk>

Acked-by: Laurent Pinchart <laurent.pinch...@ideasonboard.com>

> ---
> diff --git a/drivers/media/platform/omap/omap_vout.c
> b/drivers/media/platform/omap/omap_vout.c index 9935040..cb564d0 100644
> --- a/drivers/media/platform/omap/omap_vout.c
> +++ b/drivers/media/platform/omap/omap_vout.c
> @@ -207,19 +207,21 @@ static u32 omap_vout_uservirt_to_phys(u32 virtp)
>       struct vm_area_struct *vma;
>       struct mm_struct *mm = current->mm;
> 
> -     vma = find_vma(mm, virtp);
>       /* For kernel direct-mapped memory, take the easy way */
> -     if (virtp >= PAGE_OFFSET) {
> -             physp = virt_to_phys((void *) virtp);
> -     } else if (vma && (vma->vm_flags & VM_IO) && vma->vm_pgoff) {
> +     if (virtp >= PAGE_OFFSET)
> +             return virt_to_phys((void *) virtp);
> +
> +     down_read(&current->mm->mmap_sem);
> +     vma = find_vma(mm, virtp);
> +     if (vma && (vma->vm_flags & VM_IO) && vma->vm_pgoff) {
>               /* this will catch, kernel-allocated, mmaped-to-usermode
>                  addresses */
>               physp = (vma->vm_pgoff << PAGE_SHIFT) + (virtp - vma->vm_start);
> +             up_read(&current->mm->mmap_sem);
>       } else {
>               /* otherwise, use get_user_pages() for general userland pages */
>               int res, nr_pages = 1;
>               struct page *pages;
> -             down_read(&current->mm->mmap_sem);
> 
>               res = get_user_pages(current, current->mm, virtp, nr_pages, 1,
>                               0, &pages, NULL);

-- 
Regards,

Laurent Pinchart

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/