[RFC PATCH 0/3] allow fallback to swiotlb on hw iommu init failures

[Chris Wright <chrisw@sous-sol.org>]

This short series gives us the ability to allocate the swiotlb and then
conditionally free it if we discover it isn't needed.  This allows us to
put swiotlb to use when the hw iommu fails to initialize properly.

This needs some changes to the bootmem allocator to give the ability to
free reserved bootmem directly to the page allocator after bootmem is
torn down.

 arch/x86/include/asm/swiotlb.h |    4 ++
 arch/x86/kernel/pci-dma.c      |    4 +-
 arch/x86/kernel/pci-swiotlb.c  |   27 +++++++++---
 include/linux/bootmem.h        |    1 +
 include/linux/swiotlb.h        |    3 +
 lib/swiotlb.c                  |   10 ++++
 mm/bootmem.c                   |   98 +++++++++++++++++++++++++++++++---------
 7 files changed, 118 insertions(+), 29 deletions(-)

thanks,
-chris