Eric Lee / smarc-fsl-linux-kernel

08 Aug, 2019

1 commit

  • 79e178f43   lib: scatterlist: Fix to support no mapped sg ... Browse Code »

    In function sg_split, the second sg_calculate_split will return -EINVAL
    when in_mapped_nents is 0.

    Indeed there is no need to do second sg_calculate_split and sg_split_mapped
    when in_mapped_nents is 0, as in_mapped_nents indicates no mapped entry in
    original sgl.

    Signed-off-by: Zhou Wang
    Acked-by: Robert Jarzmik
    Signed-off-by: Jens Axboe

    Zhou Wang
     

19 Jun, 2019

1 commit

  • 40b0b3f8f   treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230 ... Browse Code »

    Based on 2 normalized pattern(s):

    this source code is licensed under the gnu general public license
    version 2 see the file copying for more details

    this source code is licensed under general public license version 2
    see

    extracted by the scancode license scanner the SPDX license identifier

    GPL-2.0-only

    has been chosen to replace the boilerplate/reference in 52 file(s).

    Signed-off-by: Thomas Gleixner
    Reviewed-by: Enrico Weigelt
    Reviewed-by: Allison Randal
    Reviewed-by: Alexios Zavras
    Cc: linux-spdx@vger.kernel.org
    Link: https://lkml.kernel.org/r/20190602204653.449021192@linutronix.de
    Signed-off-by: Greg Kroah-Hartman

    Thomas Gleixner
     

25 Aug, 2015

1 commit

  • f8bcbe62a   lib: scatterlist: add sg splitting function ... Browse Code »

    Sometimes a scatter-gather has to be split into several chunks, or sub
    scatter lists. This happens for example if a scatter list will be
    handled by multiple DMA channels, each one filling a part of it.

    A concrete example comes with the media V4L2 API, where the scatter list
    is allocated from userspace to hold an image, regardless of the
    knowledge of how many DMAs will fill it :
    - in a simple RGB565 case, one DMA will pump data from the camera ISP
    to memory
    - in the trickier YUV422 case, 3 DMAs will pump data from the camera
    ISP pipes, one for pipe Y, one for pipe U and one for pipe V

    For these cases, it is necessary to split the original scatter list into
    multiple scatter lists, which is the purpose of this patch.

    The guarantees that are required for this patch are :
    - the intersection of spans of any couple of resulting scatter lists is
    empty.
    - the union of spans of all resulting scatter lists is a subrange of
    the span of the original scatter list.
    - streaming DMA API operations (mapping, unmapping) should not happen
    both on both the resulting and the original scatter list. It's either
    the first or the later ones.
    - the caller is reponsible to call kfree() on the resulting
    scatterlists.

    Signed-off-by: Robert Jarzmik
    Signed-off-by: Jens Axboe

    Robert Jarzmik