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13525f0a62
gcc and clang warn about incompatible pointer types due to the recent
cmpxchg changes:
drivers/gpu/drm/drm_lock.c:75:10: error: passing 'typeof (lock)' (aka 'volatile unsigned int *') to parameter of type 'void *' discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]
prev = cmpxchg(lock, old, new);
^~~~~~~~~~~~~~~~~~~~~~~
include/asm-generic/atomic-instrumented.h:1685:2: note: expanded from macro 'cmpxchg'
arch_cmpxchg(__ai_ptr, __VA_ARGS__); \
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
To avoid this simply cast pointers to unsigned long and use them
instead of void pointers. This allows to stay with functions, instead
of using complex defines and having to deal with all their potential
side effects.
Reported-by: kernel test robot <lkp@intel.com>
Fixes: d2b1f6d2d3 ("s390/cmpxchg: get rid of gcc atomic builtins")
Link: https://lore.kernel.org/linux-s390/202104130131.sMmSqpb5-lkp@intel.com/
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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.