From 86e5b478325a0f5422fc6edff9db168d44852d2e Mon Sep 17 00:00:00 2001 From: Dmitry Eremin-Solenikov Date: Fri, 5 May 2017 01:00:08 +0300 Subject: linux-generic: rwlock: fix odp_rwlock_read_trylock() odp_rwlock_read_trylock() currently works only if there are no readers (and writers) as it compares counter with 0. Make it actually work in case there are other active readers. Fixes: https://bugs.linaro.org/show_bug.cgi?id=2974 Signed-off-by: Dmitry Eremin-Solenikov Reviewed-by: Bill Fischofer Signed-off-by: Maxim Uvarov --- platform/linux-generic/odp_rwlock.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'platform/linux-generic') diff --git a/platform/linux-generic/odp_rwlock.c b/platform/linux-generic/odp_rwlock.c index 13c17a2c7..5bef13a45 100644 --- a/platform/linux-generic/odp_rwlock.c +++ b/platform/linux-generic/odp_rwlock.c @@ -33,9 +33,14 @@ void odp_rwlock_read_lock(odp_rwlock_t *rwlock) int odp_rwlock_read_trylock(odp_rwlock_t *rwlock) { - uint32_t zero = 0; + uint32_t cnt = odp_atomic_load_u32(&rwlock->cnt); + + while (cnt != (uint32_t)-1) { + if (odp_atomic_cas_acq_u32(&rwlock->cnt, &cnt, cnt + 1)) + return 1; + } - return odp_atomic_cas_acq_u32(&rwlock->cnt, &zero, (uint32_t)1); + return 0; } void odp_rwlock_read_unlock(odp_rwlock_t *rwlock) -- cgit v1.2.3