Optimize ath5k_cw_validate by using the classic (X & (X - 1)) == 0
check to see if a number is power of 2.
Signed-off-by: Nick Kossifidis <mickfl...@gmail.com>
---
drivers/net/wireless/ath/ath5k/qcu.c | 10 ++++++++++
1 files changed, 10 insertions(+), 0 deletions(-)
diff --git a/drivers/net/wireless/ath/ath5k/qcu.c
b/drivers/net/wireless/ath/ath5k/qcu.c
index e50e64d..cdbaad7 100644
--- a/drivers/net/wireless/ath/ath5k/qcu.c
+++ b/drivers/net/wireless/ath/ath5k/qcu.c
@@ -111,6 +111,16 @@ ath5k_cw_validate(u16 cw_req)
u32 cw = 1;
cw_req = min(cw_req, (u16)1023);
+ /* Check if cw_req + 1 a power of 2 */
+ if (!((cw_req + 1) & cw_req))
+ return cw_req;
+
+ /* Check if cw_req is a power of 2 */
+ if (!(cw_req & (cw_req - 1)))
+ return cw_req - 1;
+
+ /* If none of the above is correct
+ * find the closest power of 2 */
while (cw < cw_req)
cw = (cw << 1) | 1;
--
1.7.8.rc1
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