[dpdk-dev] [PATCH] eal: avoid side effects in RTE_ALIGN_MUL_NEAR(v, mul) for v and mul

Tyler Retzlaff roretzla at linux.microsoft.com
Thu Mar 11 22:08:31 CET 2021


Avoid expanding v and mul parameters multiple times in the macro. based
on usage of the macro it seems like side effects were not intended.

For example:
  ``return RTE_ALIGN_MUL_NEAR(rte_rdtsc() - start, CYC_PER_10MHZ);''

Signed-off-by: Tyler Retzlaff <roretzla at linux.microsoft.com>
---
 lib/librte_eal/include/rte_common.h | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/lib/librte_eal/include/rte_common.h b/lib/librte_eal/include/rte_common.h
index 1b630baf1..640befee2 100644
--- a/lib/librte_eal/include/rte_common.h
+++ b/lib/librte_eal/include/rte_common.h
@@ -345,9 +345,11 @@ static void __attribute__((destructor(RTE_PRIO(prio)), used)) func(void)
  */
 #define RTE_ALIGN_MUL_NEAR(v, mul)				\
 	({							\
-		typeof(v) ceil = RTE_ALIGN_MUL_CEIL(v, mul);	\
-		typeof(v) floor = RTE_ALIGN_MUL_FLOOR(v, mul);	\
-		(ceil - (v)) > ((v) - floor) ? floor : ceil;	\
+		typeof(v) _v = (v);				\
+		typeof(v) _m = (mul);				\
+		typeof(v) ceil = RTE_ALIGN_MUL_CEIL(_v, _m);	\
+		typeof(v) floor = RTE_ALIGN_MUL_FLOOR(_v, _m);	\
+		(ceil - (_v)) > ((_v) - floor) ? floor : ceil;	\
 	})
 
 /**
-- 
2.30.0.vfs.0.2



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