Enable callbacks on first device attach, disable callbacks
on last device attach.
PPC64 IOMMU does memseg walk, which will cause a deadlock on
trying to do it inside a callback, so provide a local,
thread-unsafe copy of memseg walk.
PPC64 IOMMU also may remap the entire memory map for DMA while
adding new elements to it, so change user map list lock to a
recursive lock. That way, we can safely enter rte_vfio_dma_map(),
lock the user map list, enter DMA mapping function and lock the
list again (for reading previously existing maps).
git.droids-corp.org / dpdk.git / commit