[dpdk-dev] [PATCH v3] eal: fix argument to rte_bsf32_safe

[Stephen Hemminger <stephen@networkplumber.org>]

The first argument to rte_bsf32_safe was incorrectly declared as
a 64 bit value. The code only works on 32 bit values and the underlying
function rte_bsf32 only accepts 32 bit values. This was a mistake
introduced when the safe version was added and probably cause
by copy/paste from the 64 bit version.

The bug passed silently under the radar until some other code was
built with -Wall and -Wextra in C++ and C++ complains about the
missing cast.

Yes, this is a API signature change, but the original code was wrong.
It is an inline so not an ABI change.

Fixes: 4e261f551986 ("eal: add 64-bit bsf and 32-bit safe bsf functions")
Cc: anatoly.burakov@intel.com
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
---
v3 - reword commit description for checkpatch

 doc/guides/rel_notes/release_21_08.rst | 4 ++++
 lib/eal/include/rte_common.h           | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/doc/guides/rel_notes/release_21_08.rst b/doc/guides/rel_notes/release_21_08.rst
index e2c5ccbf7d90..148405891fcb 100644
--- a/doc/guides/rel_notes/release_21_08.rst
+++ b/doc/guides/rel_notes/release_21_08.rst
@@ -196,6 +196,10 @@ API Changes
   to be thread safe; all Rx queues affected by the API will now need to be
   stopped before making any changes to the power management scheme.
 
+* eal: ``rte_bsf32_safe`` now takes a 32 bit value for its first
+  argument. This fixes warnings about loss of precision when used
+  with some compilers settings.
+
 
 ABI Changes
 -----------
diff --git a/lib/eal/include/rte_common.h b/lib/eal/include/rte_common.h
index d5a32c66a5fe..99eb5f1820ae 100644
--- a/lib/eal/include/rte_common.h
+++ b/lib/eal/include/rte_common.h
@@ -623,7 +623,7 @@ rte_bsf32(uint32_t v)
  *     Returns 0 if ``v`` was 0, otherwise returns 1.
  */
 static inline int
-rte_bsf32_safe(uint64_t v, uint32_t *pos)
+rte_bsf32_safe(uint32_t v, uint32_t *pos)
 {
 	if (v == 0)
 		return 0;
-- 
2.30.2