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[ Upstream commit 4453545b5b ]
The drm buddy allocator tests were broken on 32-bit systems, as
rounddown_pow_of_two() takes a long, and the buddy allocator handles
64-bit sizes even on 32-bit systems.
This can be reproduced with the drm_buddy_allocator KUnit tests on i386:
./tools/testing/kunit/kunit.py run --arch i386 \
--kunitconfig ./drivers/gpu/drm/tests drm_buddy
(It results in kernel BUG_ON() when too many blocks are created, due to
the block size being too small.)
This was independently uncovered (and fixed) by Luís Mendes, whose patch
added a new u64 variant of rounddown_pow_of_two(). This version instead
recalculates the size based on the order.
Reported-by: Luís Mendes <luis.p.mendes@gmail.com>
Link: https://lore.kernel.org/lkml/CAEzXK1oghXAB_KpKpm=-CviDQbNaH0qfgYTSSjZgvvyj4U78AA@mail.gmail.com/T/
Signed-off-by: David Gow <davidgow@google.com>
Acked-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Arunpravin Paneer Selvam <arunpravin.paneerselvam@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230329065532.2122295-1-davidgow@google.com
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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.