• Jason Gunthorpe's avatar
    lib/scatterlist: Provide a DMA page iterator · d901b276
    Jason Gunthorpe authored
    Commit 2db76d7c ("lib/scatterlist: sg_page_iter: support sg lists w/o
    backing pages") introduced the sg_page_iter_dma_address() function without
    providing a way to use it in the general case. If the sg_dma_len() is not
    equal to the sg length callers cannot safely use the
    for_each_sg_page/sg_page_iter_dma_address combination.
    
    Resolve this API mistake by providing a DMA specific iterator,
    for_each_sg_dma_page(), that uses the right length so
    sg_page_iter_dma_address() works as expected with all sglists.
    
    A new iterator type is introduced to provide compile-time safety against
    wrongly mixing accessors and iterators.
    
    Acked-by: Christoph Hellwig <hch@lst.de> (for scatterlist)
    Acked-by: default avatarThomas Hellstrom <thellstrom@vmware.com>
    Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> (ipu3-cio2)
    Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
    d901b276
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