[PATCH] usbnet: test off by one

[PATCH] usbnet: test off by one

[Roel Kluin]

With `while (i++ < MII_TIMEOUT)' i reaches MII_TIMEOUT + 1 after the loop
This is probably unlikely a problem in practice.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
 drivers/net/usb/rtl8150.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/usb/rtl8150.c b/drivers/net/usb/rtl8150.c
index f14d225..fd19db0 100644
--- a/drivers/net/usb/rtl8150.c
+++ b/drivers/net/usb/rtl8150.c
@@ -270,7 +270,7 @@ static int read_mii_word(rtl8150_t * dev, u8 phy, __u8 indx, u16 * reg)
 		get_registers(dev, PHYCNT, 1, data);
 	} while ((data[0] & PHY_GO) && (i++ < MII_TIMEOUT));
 
-	if (i < MII_TIMEOUT) {
+	if (i <= MII_TIMEOUT) {
 		get_registers(dev, PHYDAT, 2, data);
 		*reg = data[0] | (data[1] << 8);
 		return 0;
@@ -295,7 +295,7 @@ static int write_mii_word(rtl8150_t * dev, u8 phy, __u8 indx, u16 reg)
 		get_registers(dev, PHYCNT, 1, data);
 	} while ((data[0] & PHY_GO) && (i++ < MII_TIMEOUT));
 
-	if (i < MII_TIMEOUT)
+	if (i <= MII_TIMEOUT)
 		return 0;
 	else
 		return 1;

Re: [PATCH] usbnet: test off by one

[Petko Manolov]

 	Hey Roel,

MII_TIMEOUT is a number i made up myself, reasonably small so the driver 
won't sit there forever, but higher than 2.  While testing the gadget i 
discovered that reading MII registers sometimes require more than one 
attempt.

Technically you're right.  In practice it doesn't matter much.  Hitting 
the boundary condition mean things are already out of hand.


 		Petko



On Sun, 27 Dec 2009, Roel Kluin wrote:

> With `while (i++ < MII_TIMEOUT)' i reaches MII_TIMEOUT + 1 after the loop
> This is probably unlikely a problem in practice.
>
> Signed-off-by: Roel Kluin <roel.kluin-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
> drivers/net/usb/rtl8150.c |    4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/usb/rtl8150.c b/drivers/net/usb/rtl8150.c
> index f14d225..fd19db0 100644
> --- a/drivers/net/usb/rtl8150.c
> +++ b/drivers/net/usb/rtl8150.c
> @@ -270,7 +270,7 @@ static int read_mii_word(rtl8150_t * dev, u8 phy, __u8 indx, u16 * reg)
> 		get_registers(dev, PHYCNT, 1, data);
> 	} while ((data[0] & PHY_GO) && (i++ < MII_TIMEOUT));
>
> -	if (i < MII_TIMEOUT) {
> +	if (i <= MII_TIMEOUT) {
> 		get_registers(dev, PHYDAT, 2, data);
> 		*reg = data[0] | (data[1] << 8);
> 		return 0;
> @@ -295,7 +295,7 @@ static int write_mii_word(rtl8150_t * dev, u8 phy, __u8 indx, u16 reg)
> 		get_registers(dev, PHYCNT, 1, data);
> 	} while ((data[0] & PHY_GO) && (i++ < MII_TIMEOUT));
>
> -	if (i < MII_TIMEOUT)
> +	if (i <= MII_TIMEOUT)
> 		return 0;
> 	else
> 		return 1;
>
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Re: [PATCH] usbnet: test off by one

[David Miller]

From: Roel Kluin <roel.kluin@gmail.com>
Date: Sun, 27 Dec 2009 22:22:08 +0100

> With `while (i++ < MII_TIMEOUT)' i reaches MII_TIMEOUT + 1 after the loop
> This is probably unlikely a problem in practice.
> 
> Signed-off-by: Roel Kluin <roel.kluin@gmail.com>

Applied.