2018-07-27 08:52:05

by Jia-Ju Bai

Subject: [PATCH] net: wireless: realtek: rtl8225se: Replace mdelay() with msleep() in rtl8225se_rf_init

rtl8225se_rf_init() is never called in atomic context.
It calls mdelay() to busily wait, which is not necessary.
mdelay() can be replaced with msleep().
This patch only replaces the mdelay() that has >20ms time to wait.

This is found by a static analysis tool named DCNS written by myself.

Signed-off-by: Jia-Ju Bai <[email protected]>
---
drivers/net/wireless/realtek/rtl818x/rtl8180/rtl8225se.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtl818x/rtl8180/rtl8225se.c b/drivers/net/wireless/realtek/rtl818x/rtl8180/rtl8225se.c
index fde89866fa8d..51e32df6120b 100644
--- a/drivers/net/wireless/realtek/rtl818x/rtl8180/rtl8225se.c
+++ b/drivers/net/wireless/realtek/rtl818x/rtl8180/rtl8225se.c
@@ -363,7 +363,7 @@ void rtl8225se_rf_init(struct ieee80211_hw *dev)
rtl8187se_rf_writereg(dev, 0x00, 0x0037); mdelay(11);
rtl8187se_rf_writereg(dev, 0x04, 0x0160); mdelay(11);
rtl8187se_rf_writereg(dev, 0x07, 0x0080); mdelay(11);
- rtl8187se_rf_writereg(dev, 0x02, 0x088D); mdelay(221);
+ rtl8187se_rf_writereg(dev, 0x02, 0x088D); msleep(221);
rtl8187se_rf_writereg(dev, 0x00, 0x0137); mdelay(11);
rtl8187se_rf_writereg(dev, 0x07, 0x0000); mdelay(1);
rtl8187se_rf_writereg(dev, 0x07, 0x0180); mdelay(1);
@@ -386,7 +386,7 @@ void rtl8225se_rf_init(struct ieee80211_hw *dev)
rtl8187se_rf_writereg(dev, 0x00, 0x00BF); mdelay(1);
rtl8187se_rf_writereg(dev, 0x0D, 0x08DF); mdelay(1);
rtl8187se_rf_writereg(dev, 0x02, 0x004D); mdelay(1);
- rtl8187se_rf_writereg(dev, 0x04, 0x0975); mdelay(31);
+ rtl8187se_rf_writereg(dev, 0x04, 0x0975); msleep(31);
rtl8187se_rf_writereg(dev, 0x00, 0x0197); mdelay(1);
rtl8187se_rf_writereg(dev, 0x05, 0x05AB); mdelay(1);

--
2.17.0

2018-07-31 07:28:07

by Kalle Valo

Subject: Re: [PATCH] rtl818x: Replace mdelay() with msleep() in rtl8225se_rf_init

Jia-Ju Bai <[email protected]> wrote:

> rtl8225se_rf_init() is never called in atomic context.
> It calls mdelay() to busily wait, which is not necessary.
> mdelay() can be replaced with msleep().
> This patch only replaces the mdelay() that has >20ms time to wait.
>
> This is found by a static analysis tool named DCNS written by myself.
>
> Signed-off-by: Jia-Ju Bai <[email protected]>

Patch applied to wireless-drivers-next.git, thanks.

622e938240db rtl818x: Replace mdelay() with msleep() in rtl8225se_rf_init

--
https://patchwork.kernel.org/patch/10546749/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches