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From: "Mattias Rönnblom" <mattias.ronnblom@ericsson.com>
To: <dev@dpdk.org>, Jack Bond-Preston <jack.bond-preston@foss.arm.com>
Cc: "Mattias Rönnblom" <hofors@lysator.liu.se>,
	"Mattias Rönnblom" <mattias.ronnblom@ericsson.com>,
	stable@dpdk.org
Subject: [PATCH] bitops: improve power of 2 alignment function documentation
Date: Tue, 22 Jul 2025 09:53:21 +0200	[thread overview]
Message-ID: <20250722075321.121254-1-mattias.ronnblom@ericsson.com> (raw)

In the documentation, make clear
rte_align(32|64)prevpow2(<n>) -> <n>, provided <n> is a power of 2.

The original documentation stated the "previous" power of 2 would be
returned, potentially leaving the user to erroneously conclude that,
for example, rte_align32prevpow2(32) -> 16.

The rte_align(32|64)pow2(<n>) documentation, suffering from a similar
issue, is reworded in the same manner.

Fixes: 08f683174e94 ("eal: add functions for previous power of 2 alignment")
Cc: stable@dpdk.org

Signed-off-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
---
 lib/eal/include/rte_bitops.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/lib/eal/include/rte_bitops.h b/lib/eal/include/rte_bitops.h
index b9a6af381b..2d1b9d281c 100644
--- a/lib/eal/include/rte_bitops.h
+++ b/lib/eal/include/rte_bitops.h
@@ -1320,7 +1320,7 @@ rte_is_power_of_2(uint32_t n)
  *   The integer value to align
  *
  * @return
- *   Input parameter aligned to the next power of 2
+ *   The smallest power of 2 which is greater than or equal to @c x.
  */
 static inline uint32_t
 rte_align32pow2(uint32_t x)
@@ -1338,7 +1338,7 @@ rte_align32pow2(uint32_t x)
  *   The integer value to align
  *
  * @return
- *   Input parameter aligned to the previous power of 2
+ *   The greatest power of 2 which is smaller than or equal to @c x.
  */
 static inline uint32_t
 rte_align32prevpow2(uint32_t x)
@@ -1355,7 +1355,7 @@ rte_align32prevpow2(uint32_t x)
  *   The 64b value to align
  *
  * @return
- *   Input parameter aligned to the next power of 2
+ *   The smallest power of 2 which is greater than or equal to @c v.
  */
 static inline uint64_t
 rte_align64pow2(uint64_t v)
@@ -1373,7 +1373,7 @@ rte_align64pow2(uint64_t v)
  *   The 64b value to align
  *
  * @return
- *   Input parameter aligned to the previous power of 2
+ *   The greatest power of 2 which is smaller than or equal to @c v.
  */
 static inline uint64_t
 rte_align64prevpow2(uint64_t v)
-- 
2.43.0


             reply	other threads:[~2025-07-22  8:08 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-22  7:53 Mattias Rönnblom [this message]
2025-07-22  8:40 ` Bruce Richardson
2025-07-22 10:29   ` Morten Brørup

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