• Robin Murphy's avatar
    dma-debug: check scatterlist segments · 78c47830
    Robin Murphy authored
    Drivers/subsystems creating scatterlists for DMA should be taking care
    to respect the scatter-gather limitations of the appropriate device, as
    described by dma_parms. A DMA API implementation cannot feasibly split
    a scatterlist into *more* entries than originally passed, so it is not
    well defined what they should do when given a segment larger than the
    limit they are also required to respect.
    
    Conversely, devices which are less limited than the rather conservative
    defaults, or indeed have no limitations at all (e.g. GPUs with their own
    internal MMU), should be encouraged to set appropriate dma_parms, as
    they may get more efficient DMA mapping performance out of it.
    Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
    Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
    78c47830
Kconfig.debug 67.6 KB