On Thu, Jul 11, 2013 at 5:43 PM, Jean-S?bastien P?dron <jean-sebastien.pedron at dumbbell.fr> wrote: > Hi, > > Thank you J?r?me and Daniel for your input, that's really helpful! > > I have another question: in ttm_bo_mmap(), a reference to the buffer object > is acquired at the beginning of the function. Another reference is acquired > in ttm_bo_vm_open() (released in ttm_bo_vm_close()). > > But where is the first reference released? > > -- > Jean-S?bastien P?dron
the ttm_bo_vm_open is not call on first time a vma is mmap, ie when userspace do mmap it call driver mmap callback which call ttm_bo_mmap but ttm_bo_vm_open is never call. If the same process or another process mmap the same area or subarea the ttm_bo_vm_open is call. Then on each unmap ttm_bo_vm_close is call. Cheers, Jerome
