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db9c1734ad
When we swapout/in a BO we try to change the caching attributes of the pages before/after doing the copy. On x86 this is done by calling set_pages_uc(), set_memory_wc() or set_pages_wb() for not highmem pages to update the linear mapping of the page. On all other platforms we do exactly nothing. Now on x86 this is unnecessary because copy_highpage() will either create a temporary mapping of the page which is wb anyway and destroyed immediately again or use the linear mapping with the correct caching attributes. So stop this nonsense and just keep the caching as it is and return an error when a driver tries to change the caching of an already populated TT object. This is much more defensive since changing caching attributes is platform and driver specific and usually doesn't work after the page was initially allocated. Signed-off-by: Christian König <christian.koenig@amd.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Link: https://patchwork.freedesktop.org/patch/391293/
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.