From 1587d36e22d0cf0e037a104e1e851acefd6597f0 Mon Sep 17 00:00:00 2001 From: Andy Green Date: Tue, 22 May 2018 09:24:17 +0800 Subject: [PATCH] eal: explicit cast in rwlock functions GCC 8.1 warned: In function 'rte_rwlock_read_lock': rte_rwlock.h:74:12: warning: conversion to 'uint32_t' {aka 'unsigned int'} from 'int32_t' {aka 'int'} may change the sign of the result [-Wsign-conversion] x, x + 1); ^ rte_rwlock.h:74:17: warning: conversion to 'uint32_t' {aka 'unsigned int'} from 'int' may change the sign of the result [-Wsign-conversion] x, x + 1); ~~^~~ In function 'rte_rwlock_write_lock': rte_rwlock.h:110:15: warning: unsigned conversion from 'int' to 'uint32_t' {aka 'unsigned int'} changes value from '-1' to '4294967295' [-Wsign-conversion] 0, -1); ^~ Again in this case we are making explicit the exact cast that was always happening implicitly. The patch does not change the generated code. The int32_t temp "x" is required to be signed to detect a < 0 error condition from the lock status. Afterwards, it has always been implicitly cast to uint32_t when it is used in the arguments to rte_atomic32_cmpset()... gcc8.1 objects to the implicit cast now and requires us to cast it explicitly. Fixes: af75078fec ("first public release") Cc: stable@dpdk.org Signed-off-by: Andy Green Acked-by: Bruce Richardson --- lib/librte_eal/common/include/generic/rte_rwlock.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/lib/librte_eal/common/include/generic/rte_rwlock.h b/lib/librte_eal/common/include/generic/rte_rwlock.h index 899e9bc43d..5751a0e6d5 100644 --- a/lib/librte_eal/common/include/generic/rte_rwlock.h +++ b/lib/librte_eal/common/include/generic/rte_rwlock.h @@ -71,7 +71,7 @@ rte_rwlock_read_lock(rte_rwlock_t *rwl) continue; } success = rte_atomic32_cmpset((volatile uint32_t *)&rwl->cnt, - x, x + 1); + (uint32_t)x, (uint32_t)(x + 1)); } } @@ -107,7 +107,7 @@ rte_rwlock_write_lock(rte_rwlock_t *rwl) continue; } success = rte_atomic32_cmpset((volatile uint32_t *)&rwl->cnt, - 0, -1); + 0, (uint32_t)-1); } } -- 2.20.1