Since commit 295525e29a5b ("virtio_net: merge dma operations when filling mergeable buffers"), VDUSE device require support for DMA's .sync_single_for_cpu() operation as the memory is non-coherent between the device and CPU because of the use of a bounce buffer. This patch implements both .sync_single_for_cpu() and .sync_single_for_device() callbacks, and also skip bounce buffer copies during DMA map and unmap operations if the DMA_ATTR_SKIP_CPU_SYNC attribute is set to avoid extra copies of the same buffer. Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com> Message-Id: <20240219170606.587290-1-maxime.coquelin@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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