Use of copy_from_user in msm_gem_submit.c while holding a spin_lock

[Vaishali Thakkar]

Hello,

I was wondering about the call to copy_from_user in function submit_lookup_objects for drive
/gpu/drm/msm/msm_gem_submit.c  It calls copy_from_user[1] in a spin_lock, which is not normally
allowed, due to the possibility of a deadlock.  

Is there some reason that I am overlooking why it is OK in this case? Is there some code in the
same file which ensures that page fault will not occur when we are calling the function holding
spin_lock?

Thank you.

[1] http://lxr.free-electrons.com/source/drivers/gpu/drm/msm/msm_gem_submit.c#L85

-- 
Vaishali