| Message ID | 20200101100500.658787-1-chris@chris-wilson.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915/gem: Drop local vma->vm_file reference | expand |
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c index 4caf7d750c34..3c5695a2858a 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c @@ -751,6 +751,10 @@ int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma) vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; vma->vm_private_data = mmo; + if (vma->vm_file) { /* we keep mmo->obj ref, not vm_file */ + fput(vma->vm_file); + vma->vm_file = NULL; + } switch (mmo->mmap_type) { case I915_MMAP_TYPE_WC:
We use the global device inode, shared amongst all files, and not the user's device filp to provide the backing storage for the mmap. The vma->vm_file provides a redundant reference that breaks existing expected behaviour that closing the user's device fd will release the resources bound to it, if a mmap persists. (Even without the vma->vm_file, the mmap will persist past the user's fd as the storage is bound to the device, i.e. our reference is on the object not file.) Fixes: cc662126b413 ("drm/i915: Introduce DRM_I915_GEM_MMAP_OFFSET") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> --- drivers/gpu/drm/i915/gem/i915_gem_mman.c | 4 ++++ 1 file changed, 4 insertions(+)