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usbnet: test off by one

PATCH Applied Roel Kluin 3 participants 3 messages Dec 27, 2009 – Jan 4, 2010

Subsystems (4)
Networking Network drivers USB networking drivers USB RTL8150 driver
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Roel Kluin

author
#0 lore raw

PATCH 1/1 usbnet: test off by one

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 <[email protected]>
---
 drivers/net/usb/rtl8150.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
drivers/net/usb/rtl8150.c +2 -2
index f14d225..fd19db0 100644
@@ -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;
maintainer
#1 lore raw

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

Quoted 23 lines · 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 <[email protected]>

---
drivers/net/usb/rtl8150.c | 4 ++--

1 files changed, 2 insertions(+), 2 deletions(-)
drivers/net/usb/rtl8150.c +1 -1
index f14d225..fd19db0 100644
@@ -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;

drivers/net/usb/rtl8150.c static int write_mii_word(rtl8150_t * dev, u8 phy, __u8 indx, u16 reg) · line 301

Quoted 8 lines
drivers/net/usb/rtl8150.c +1 -1
@@ -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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