From: Steven Rostedt Date: Fri, 25 Mar 2011 20:21:06 +0000 (-0400) Subject: WARN_ON_SMP(): Add comment to explain ({0;}) X-Git-Tag: v2.6.39-rc2~22^2~1 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ccd0d44fad38dc1bb4b26dcc7a30e9f2c3b36870;p=pandora-kernel.git WARN_ON_SMP(): Add comment to explain ({0;}) The define to use ({0;}) for the !CONFIG_SMP case of WARN_ON_SMP() can be confusing. As the WARN_ON_SMP() needs to be a nop when CONFIG_SMP is not set, including all its parameters must not be evaluated, and that it must work as both a stand alone statement and inside an if condition, we define it to a funky ({0;}). A simple "0" will not work as it causes gcc to give the warning that the statement has no effect. As this strange definition has raised a few eyebrows from some major kernel developers, it is wise to document why we create such a work of art. Cc: Linus Torvalds Cc: Alexey Dobriyan Signed-off-by: Steven Rostedt --- Reading git-diff-tree failed