[Intel-gfx] [PATCH v3 3/3] drm/vgem: Keep a reference to the dmabuf when mmaped
Chris Wilson
chris at chris-wilson.co.uk
Fri Sep 30 13:59:59 UTC 2016
In order to keep the dmabuf alive whilst the mmap is, we need to hold a
reference to the dmabuf and not the backing object. This is important as
the dmabuf not only keeps the object alive, but also the device so that
dmabuf = vgem_create_dmabuf();
ptr = mmap(... dmabuf ...);
close(dmabuf);
persists across module-unload as well as device closure.
Testcase: igt/vgem_basic/unload
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Petri Latvala <petri.latvala at intel.com>
---
drivers/gpu/drm/vgem/vgem_drv.c | 17 +++--------------
1 file changed, 3 insertions(+), 14 deletions(-)
diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c
index f36c14729b55..74a83e41efa9 100644
--- a/drivers/gpu/drm/vgem/vgem_drv.c
+++ b/drivers/gpu/drm/vgem/vgem_drv.c
@@ -198,7 +198,6 @@ static struct drm_ioctl_desc vgem_ioctls[] = {
static int vgem_mmap(struct file *filp, struct vm_area_struct *vma)
{
- unsigned long flags = vma->vm_flags;
int ret;
ret = drm_gem_mmap(filp, vma);
@@ -208,7 +207,7 @@ static int vgem_mmap(struct file *filp, struct vm_area_struct *vma)
/* Keep the WC mmaping set by drm_gem_mmap() but our pages
* are ordinary and not special.
*/
- vma->vm_flags = flags | VM_DONTEXPAND | VM_DONTDUMP;
+ vma->vm_flags &= ~(VM_IO | VM_PFNMAP);
return 0;
}
@@ -281,21 +280,11 @@ static int vgem_prime_mmap(struct drm_gem_object *obj,
{
int ret;
- if (obj->size < vma->vm_end - vma->vm_start)
- return -EINVAL;
-
- if (!obj->filp)
- return -ENODEV;
-
- ret = obj->filp->f_op->mmap(obj->filp, vma);
+ ret = drm_gem_mmap_obj(obj, obj->size, vma);
if (ret)
return ret;
- fput(vma->vm_file);
- vma->vm_file = get_file(obj->filp);
- vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
- vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
-
+ vma->vm_flags &= ~(VM_IO | VM_PFNMAP);
return 0;
}
--
2.9.3
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