From e51b156b18fb6d34a1e409d153040a02adb5c7e0 Mon Sep 17 00:00:00 2001 From: Uwe Kleine-König Date: Fri, 2 Dec 2022 19:35:09 +0100 Subject: pwm: Document variables protected by pwm_lock MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit To simplify validation of the used locking, document for the global pwm mutex what it actually protects against concurrent access. Also note for two functions modifying these that pwm_lock is held by the caller. Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20221117211143.3817381-2-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König Signed-off-by: Thierry Reding --- drivers/pwm/core.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'drivers/pwm') diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index d333e7422f4a..ebe06efe9de5 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -27,7 +27,10 @@ static DEFINE_MUTEX(pwm_lookup_lock); static LIST_HEAD(pwm_lookup_list); + +/* protects access to pwm_chips, allocated_pwms, and pwm_tree */ static DEFINE_MUTEX(pwm_lock); + static LIST_HEAD(pwm_chips); static DECLARE_BITMAP(allocated_pwms, MAX_PWMS); static RADIX_TREE(pwm_tree, GFP_KERNEL); @@ -37,6 +40,7 @@ static struct pwm_device *pwm_to_device(unsigned int pwm) return radix_tree_lookup(&pwm_tree, pwm); } +/* Called with pwm_lock held */ static int alloc_pwms(unsigned int count) { unsigned int start; @@ -50,6 +54,7 @@ static int alloc_pwms(unsigned int count) return start; } +/* Called with pwm_lock held */ static void free_pwms(struct pwm_chip *chip) { unsigned int i; -- cgit v1.2.3-58-ga151