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c8603d6928
Rewrite __cmpxchg() in order to get rid of the large inline assemblies. Convert the one and two byte inline assemblies to C functions. The generated code of the new implementation is nearly as good or bad as the old variant, but easier to read. Note that the new variants are quite close to the generic cmpxchg_emu_u8() implementation, however a conversion to the generic variant will not follow since with mm/vmstat.c there is heavy user of one byte cmpxchg(). A not inlined variant would have a negative performance impact. Also note that the calls within __arch_cmpxchg() come with rather pointless "& 0xff..." operations. They exist only to avoid false positive sparse warnings like "warning: cast truncates bits from constant value ...". Reviewed-by: Juergen Christ <jchrist@linux.ibm.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 reStructuredText 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.