| Message ID | 20221115211515.3750209-2-u.kleine-koenig@pengutronix.de |
|---|---|
| State | Superseded |
| Headers | show |
| Series | pwm: Some refactoring of pwmchip_add() | expand |
On Tue, Nov 15, 2022 at 10:15:12PM +0100, Uwe Kleine-König wrote: > 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 <andriy.shevchenko@linux.intel.com> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > --- > drivers/pwm/core.c | 5 +++++ > 1 file changed, 5 insertions(+) > > 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; > -- > 2.38.1 >
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;
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. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> --- drivers/pwm/core.c | 5 +++++ 1 file changed, 5 insertions(+)