Messages in this thread Patch in this message | | | Date | Sun, 17 Oct 2010 17:18:15 +0200 | From | Jan Kiszka <> | Subject | [PATCH v2] CAPI: Silence lockdep warning on get_capi_appl_by_nr usage |
| |
As long as we hold capi_controller_lock, we can safely access capi_applications without RCU protection as no one can modify the application list underneath us. Introduce an RCU-free __get_capi_appl_by_nr for this purpose. This silences lockdep warnings on suspicious rcu_dereference usage.
Signed-off-by: Jan Kiszka <jan.kiszka@web.de> ---
v2: - use lockdep_assert_held in favor of WARN_ON_ONCE(!mutex_is_locked) as suggested by Peter
drivers/isdn/capi/kcapi.c | 19 ++++++++++++++----- 1 files changed, 14 insertions(+), 5 deletions(-)
diff --git a/drivers/isdn/capi/kcapi.c b/drivers/isdn/capi/kcapi.c index 2648d39..2b33b26 100644 --- a/drivers/isdn/capi/kcapi.c +++ b/drivers/isdn/capi/kcapi.c @@ -99,6 +99,16 @@ static inline struct capi_ctr *get_capi_ctr_by_nr(u16 contr) return capi_controller[contr - 1]; } +static inline struct capi20_appl *__get_capi_appl_by_nr(u16 applid) +{ + lockdep_assert_held(&capi_controller_lock); + + if (applid - 1 >= CAPI_MAXAPPL) + return NULL; + + return capi_applications[applid - 1]; +} + static inline struct capi20_appl *get_capi_appl_by_nr(u16 applid) { if (applid - 1 >= CAPI_MAXAPPL) @@ -186,10 +196,9 @@ static void notify_up(u32 contr) ctr->state = CAPI_CTR_RUNNING; for (applid = 1; applid <= CAPI_MAXAPPL; applid++) { - ap = get_capi_appl_by_nr(applid); - if (!ap) - continue; - register_appl(ctr, applid, &ap->rparam); + ap = __get_capi_appl_by_nr(applid); + if (ap) + register_appl(ctr, applid, &ap->rparam); } wake_up_interruptible_all(&ctr->state_wait_queue); @@ -216,7 +225,7 @@ static void ctr_down(struct capi_ctr *ctr, int new_state) memset(ctr->serial, 0, sizeof(ctr->serial)); for (applid = 1; applid <= CAPI_MAXAPPL; applid++) { - ap = get_capi_appl_by_nr(applid); + ap = __get_capi_appl_by_nr(applid); if (ap) capi_ctr_put(ctr); } -- 1.7.1
| |