[PATCH v3 0/3] UIO_MEM_DMA_COHERENT for cnic/bnx2/bnx2x

[Nilesh Javali <njavali@marvell.com>]

During bnx2i iSCSI testing we ran into page refcounting issues in the
uio mmaps exported from cnic to the iscsiuio process, and bisected back
to the removal of the __GFP_COMP flag from dma_alloc_coherent calls.

In order to fix these drivers to be able to mmap dma coherent memory via
a uio device, without resorting to hacks and working with an iommu
enabled, introduce a new uio mmap type backed by dma_mmap_coherent.

While converting the uio interface, I also noticed that not all of these
allocations were PAGE_SIZE aligned. Particularly the bnx2/bnx2x status
block mapping was much smaller than any architecture page size, and I
was concerned that it could be unintentionally exposing kernel memory.

v3:
- fix warnings reported by kernel test robot
  and added base commit
v2:
- expose only the dma_addr within uio and cnic.
- Cleanup newly added unions comprising virtual_addr
  and struct device

Chris Leech (3):
  uio: introduce UIO_MEM_DMA_COHERENT type
  cnic,bnx2,bnx2x: use UIO_MEM_DMA_COHERENT
  cnic,bnx2,bnx2x: page align uio mmap allocations

 drivers/net/ethernet/broadcom/bnx2.c          |  2 +
 .../net/ethernet/broadcom/bnx2x/bnx2x_main.c  | 10 +++--
 drivers/net/ethernet/broadcom/cnic.c          | 20 +++++++---
 drivers/net/ethernet/broadcom/cnic.h          |  1 +
 drivers/net/ethernet/broadcom/cnic_if.h       |  1 +
 drivers/uio/uio.c                             | 40 +++++++++++++++++++
 include/linux/uio_driver.h                    |  2 +
 7 files changed, 66 insertions(+), 10 deletions(-)


base-commit: ed340d13aa1db6773667ed4bf907738df203fbda
-- 
2.23.1