• Pauli Nieminen's avatar
    drm: Add generic multipart buffer. · 7a9f0dd9
    Pauli Nieminen authored
    Allocating multiple pages of memory for data that is coming
    from user space may fail. To fix memory allocation failures
    the buffer object should be split to multiple independ pages.
    
    drm buffer provides generic interface to copy and process
    large data arrays from user space.
    
    Interface includes allocation and free functions to allocate
    the buffer object and data storage pages.
    
    All access operations are performed relative to a internal
    pointer which is advanced with drm_buffer_advance function.
    
    The buffer can be accessed using drm_buffer_pointer_to_XXX
    functions if it is known that requested object doesn't split
    over a page boundary. These functions don't do any error
    checking to maximize performance.
    
    If there is large object which could be split there is special
    drm_buffer_read_object function. drm_buffer_read_object takes
    a pointer as argument which is used as temporary store for
    data if it is split over boundary in the buffer.
    Signed-off-by: default avatarPauli Nieminen <suokkos@gmail.com>
    Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
    7a9f0dd9
drm_buffer.c 4.84 KB