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Commit 9a391691 authored by Nick Kossifidis's avatar Nick Kossifidis Committed by John W. Linville
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ath5k: Optimize ath5k_cw_validate 



Optimize ath5k_cw_validate by using the classic (X & (X - 1)) == 0
check to see if a number is power of 2.

v2: Use functions from log2.h instead

Signed-off-by: default avatarNick Kossifidis <mickflemm@gmail.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent b4cfb5d5

drivers/net/wireless/ath/ath5k/qcu.c

+13 −4
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ Queue Control Unit, DCF Control Unit Functions 
#include "ath5k.h"

#include "reg.h"

#include "debug.h"

#include <linux/log2.h>



/**

 * DOC: Queue Control Unit (QCU)/DCF Control Unit (DCU) functions
@@ -108,13 +109,21 @@ ath5k_hw_release_tx_queue(struct ath5k_hw *ah, unsigned int queue) 
static u16

ath5k_cw_validate(u16 cw_req)

{

	u32 cw = 1;

	cw_req = min(cw_req, (u16)1023);



	while (cw < cw_req)

		cw = (cw << 1) | 1;

	/* Check if cw_req + 1 a power of 2 */

	if (is_power_of_2(cw_req + 1))

		return cw_req;



	return cw;

	/* Check if cw_req is a power of 2 */

	if (is_power_of_2(cw_req))

		return cw_req - 1;



	/* If none of the above is correct

	 * find the closest power of 2 */

	cw_req = (u16) roundup_pow_of_two(cw_req) - 1;



	return cw_req;

}



/**