From: Alessandro Carminati <[email protected]> KUnit support is not consistently present across distributions, some include it in their stock kernels, while others do not. While both KUNIT and KUNIT_SUPPRESS_BACKTRACE can be considered debug features, the fact that some distros ship with KUnit enabled means it's important to minimize the runtime impact of this patch.
To that end, this patch adds an atomic counter that tracks the number of active suppressions. __kunit_is_suppressed_warning() checks this counter first and returns immediately when no suppressions are active, avoiding RCU-protected list traversal in the common case. Signed-off-by: Alessandro Carminati <[email protected]> Signed-off-by: Albert Esteve <[email protected]> --- lib/kunit/bug.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/lib/kunit/bug.c b/lib/kunit/bug.c index 356c8a5928828..a7a88f0670d44 100644 --- a/lib/kunit/bug.c +++ b/lib/kunit/bug.c @@ -8,6 +8,7 @@ #include <kunit/bug.h> #include <kunit/resource.h> +#include <linux/atomic.h> #include <linux/export.h> #include <linux/rculist.h> #include <linux/sched.h> @@ -15,11 +16,13 @@ #ifdef CONFIG_KUNIT_SUPPRESS_BACKTRACE static LIST_HEAD(suppressed_warnings); +static atomic_t suppressed_warnings_cnt = ATOMIC_INIT(0); static void __kunit_suppress_warning_remove(struct __suppressed_warning *warning) { list_del_rcu(&warning->node); synchronize_rcu(); /* Wait for readers to finish */ + atomic_dec(&suppressed_warnings_cnt); } KUNIT_DEFINE_ACTION_WRAPPER(__kunit_suppress_warning_cleanup, @@ -37,6 +40,7 @@ __kunit_start_suppress_warning(struct kunit *test) return NULL; warning->task = current; + atomic_inc(&suppressed_warnings_cnt); list_add_rcu(&warning->node, &suppressed_warnings); ret = kunit_add_action_or_reset(test, @@ -68,6 +72,9 @@ bool __kunit_is_suppressed_warning(void) { struct __suppressed_warning *warning; + if (!atomic_read(&suppressed_warnings_cnt)) + return false; + rcu_read_lock(); list_for_each_entry_rcu(warning, &suppressed_warnings, node) { if (warning->task == current) { -- 2.52.0
