From: "Steven Rostedt (Red Hat)" <rostedt@xxxxxxxxxxx> This patch has been added to the 3.18 stable tree. If you have any objections, please let us know. =============== [ 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@xxxxxxxxxx Suggested-by: Christoph Lameter <cl@xxxxxxxxx> Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx> Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx> --- kernel/trace/ring_buffer.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 0b6b667..53ffcf5 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 -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html