tree 2a2cead5f2b1123b4b4b13d307d6db035e2c13fe
parent 61e015ac5b4d46c2054a78d9bc82c840274929a0
author Alexey Kardashevskiy <aik@ozlabs.ru> 1364167429 +1100
committer Joerg Roedel <joro@8bytes.org> 1366826211 +0200

iommu: Add a function to find an iommu group by id

As IOMMU groups are exposed to the user space by their numbers,
the user space can use them in various kernel APIs so the kernel
might need an API to find a group by its ID.

As an example, QEMU VFIO on PPC64 platform needs it to associate
a logical bus number (LIOBN) with a specific IOMMU group in order
to support in-kernel handling of DMA map/unmap requests.

The patch adds the iommu_group_get_by_id(id) function which performs
such search.

v2: fixed reference counting.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>