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
