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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2015-03-27 17:39:49 -0400
committerSasha Levin <sasha.levin@oracle.com>2016-06-06 19:11:04 -0400
commit090243482940087932c879868ca3b676a6701075 (patch)
tree7f73ce8c897f6d2104cfb83a8336bf479c8d8067 /kernel
parent4baf9733a655b71db7b436484dfdc04566c3a5a3 (diff)
downloadlinux-linaro-stable-090243482940087932c879868ca3b676a6701075.tar.gz
ring-buffer: Remove duplicate use of '&' in recursive code
[ Upstream commit d631c8cceb1d1d06f372878935949d421585186b ] A clean up of the recursive protection code changed val = this_cpu_read(current_context); val--; val &= this_cpu_read(current_context); to val = this_cpu_read(current_context); val &= val & (val - 1); Which has a duplicate use of '&' as the above is the same as val = val & (val - 1); Actually, it would be best to remove that line altogether and just add it to where it is used. And Christoph even mentioned that it can be further compacted to just a single line: __this_cpu_and(current_context, __this_cpu_read(current_context) - 1); Link: http://lkml.kernel.org/alpine.DEB.2.11.1503271423580.23114@gentwo.org Suggested-by: Christoph Lameter <cl@linux.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/ring_buffer.c5
1 files changed, 1 insertions, 4 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 0b6b66720e2b..53ffcf53fcd7 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2708,10 +2708,7 @@ static __always_inline int trace_recursive_lock(void)
static __always_inline void trace_recursive_unlock(void)
{
- unsigned int val = __this_cpu_read(current_context);
-
- val &= val & (val - 1);
- __this_cpu_write(current_context, val);
+ __this_cpu_and(current_context, __this_cpu_read(current_context) - 1);
}
#else