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drm: make sure page protections are updated after changing vm_flags

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Some architectures compute ->vm_page_prot depending on ->vm_flags, so we
need to update the protections after adjusting the flags.

AFAIK this only affects running X under Xen; without this patch you get
lots of coloured blobs on the screen, or maybe a complete lockup.  Or
anything really.

But that still depends on lots of out-of-tree stuff, so I don't think
there are any consequences for anyone else.  But it is wrong in principle.

Reported-by: Jan Beulich <JBeulich@novell.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This commit is contained in:
Jeremy Fitzhardinge 2009-11-17 14:08:54 -08:00 committed by Dave Airlie
parent f82f5f3ac4
commit 79cc304f3e
1 changed files with 1 additions and 1 deletions
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2
drivers/gpu/drm/drm_gem.c
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@ -552,7 +552,7 @@ int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
vma->vm_flags |= VM_RESERVED | VM_IO | VM_PFNMAP | VM_DONTEXPAND;
vma->vm_ops = obj->dev->driver->gem_vm_ops;
vma->vm_private_data = map->handle;
vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
/* Take a ref for this mapping of the object, so that the fault
* handler can dereference the mmap offset's pointer to the object.