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SubjectRe: [PATCH] omap_vout: find_vma() needs ->mmap_sem held
Date
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 <viro@zeniv.linux.org.uk>

Acked-by: Laurent Pinchart <laurent.pinchart@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



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