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From:   Chris Leech <cleech@redhat.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Christoph Hellwig <hch@lst.de>,
        Rasesh Mody <rmody@marvell.com>,
        Ariel Elior <aelior@marvell.com>,
        Sudarsana Kalluru <skalluru@marvell.com>,
        Manish Chopra <manishc@marvell.com>
Cc:     Nilesh Javali <njavali@marvell.com>,
        Manish Rangankar <mrangankar@marvell.com>,
        Jerry Snitselaar <jsnitsel@redhat.com>,
        John Meneghini <jmeneghi@redhat.com>,
        Lee Duncan <lduncan@suse.com>,
        Mike Christie <michael.christie@oracle.com>,
        Hannes Reinecke <hare@kernel.org>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH 0/3] UIO_MEM_DMA_COHERENT for cnic/bnx2/bnx2x
Date:   Fri, 29 Sep 2023 10:00:20 -0700
Message-ID: <20230929170023.1020032-1-cleech@redhat.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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.

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

 drivers/net/ethernet/broadcom/bnx2.c          |  2 ++
 .../net/ethernet/broadcom/bnx2x/bnx2x_main.c  | 10 +++---
 drivers/net/ethernet/broadcom/cnic.c          | 34 ++++++++++++-------
 drivers/net/ethernet/broadcom/cnic.h          |  1 +
 drivers/net/ethernet/broadcom/cnic_if.h       |  1 +
 drivers/uio/uio.c                             | 34 +++++++++++++++++++
 include/linux/uio_driver.h                    | 12 +++++--
 7 files changed, 75 insertions(+), 19 deletions(-)

-- 
2.41.0