Fork of alistair23 Linux kernel for reMarkable from https://github.com/alistair23/linux
8b6b7d84bf
I honestly don't exactly understand what's going on here, but the current code is wrong for sure: It calls dma_buf_vunmap without ever calling dma_buf_vmap. What I'm not sure about is whether the WARN_ON is correct: - msm imports dma-buf using drm_prime_sg_to_page_addr_arrays. Which is a pretty neat layering violation of how you shouldn't peek behind the curtain of the dma-buf exporter, but par for course. Note that all the nice new helpers don't (and we should probably have a bit a warning about this in the kerneldoc). - but then in the get_vaddr() in msm_gem.c, we seems to happily wrap a vmap() around any object with ->pages set (so including imported dma-buf). - I'm not seeing any guarantees that userspace can't use an imported dma-buf for e.g. MSM_SUBMIT_CMD_BUF in a5xx_submit_in_rb, so no guarantees that an imported dma-buf won't end up with a ->vaddr set. But even if that WARN_ON is wrong, cleaning up a vmap() done by msm by calling dma_buf_vunmap is the wrong thing to do. v2: Rob said in review that we do indeed have a gap in get_vaddr() that needs to be plugged. But the users I've found aren't legit users on imported dma-buf, so we can just reject that. Reviewed-by: Rob Clark <robdclark@gmail.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Rob Clark <robdclark@gmail.com> Cc: Sean Paul <sean@poorly.run> Cc: linux-arm-msm@vger.kernel.org Cc: freedreno@lists.freedesktop.org Link: https://patchwork.freedesktop.org/patch/msgid/20200514201117.465146-1-daniel.vetter@ffwll.ch |
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LICENSES | ||
arch | ||
block | ||
certs | ||
crypto | ||
drivers | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.clang-format | ||
.cocciconfig | ||
.get_maintainer.ignore | ||
.gitattributes | ||
.gitignore | ||
.mailmap | ||
COPYING | ||
CREDITS | ||
Kbuild | ||
Kconfig | ||
MAINTAINERS | ||
Makefile | ||
README |
README
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.