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From: Roel Kluin <roel.kluin-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org>
Cc: "Ben Dooks (embedded platforms)"
	<ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>,
	linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Andrew Morton
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
	LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: [PATCH] i2c: test off by one in {piix4,vt596}_transaction()
Date: Tue, 05 Jan 2010 22:22:23 +0100	[thread overview]
Message-ID: <4B43AD8F.2030809@gmail.com> (raw)
In-Reply-To: <20100105175511.39dc6c42-ig7AzVSIIG7kN2dkZ6Wm7A@public.gmane.org>

With `while (timeout++ < MAX_TIMEOUT)' timeout reaches MAX_TIMEOUT + 1 after the loop
This is probably unlikely to produce a problem.

Signed-off-by: Roel Kluin <roel.kluin-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
> That's right... but I'd rather change the loops to use "++timeout" and
> leave the conditions as is (or maybe change it to "=="). I think it's
> easier to read that way. Would that be OK with you?

Ok,

 drivers/i2c/busses/i2c-piix4.c  |    4 ++--
 drivers/i2c/busses/i2c-viapro.c |    4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index 1e245e9..e56e4b6 100644
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -324,12 +324,12 @@ static int piix4_transaction(void)
 	else
 		msleep(1);
 
-	while ((timeout++ < MAX_TIMEOUT) &&
+	while ((++timeout < MAX_TIMEOUT) &&
 	       ((temp = inb_p(SMBHSTSTS)) & 0x01))
 		msleep(1);
 
 	/* If the SMBus is still busy, we give up */
-	if (timeout >= MAX_TIMEOUT) {
+	if (timeout == MAX_TIMEOUT) {
 		dev_err(&piix4_adapter.dev, "SMBus Timeout!\n");
 		result = -ETIMEDOUT;
 	}
diff --git a/drivers/i2c/busses/i2c-viapro.c b/drivers/i2c/busses/i2c-viapro.c
index e4b1543..a84a909 100644
--- a/drivers/i2c/busses/i2c-viapro.c
+++ b/drivers/i2c/busses/i2c-viapro.c
@@ -165,10 +165,10 @@ static int vt596_transaction(u8 size)
 	do {
 		msleep(1);
 		temp = inb_p(SMBHSTSTS);
-	} while ((temp & 0x01) && (timeout++ < MAX_TIMEOUT));
+	} while ((temp & 0x01) && (++timeout < MAX_TIMEOUT));
 
 	/* If the SMBus is still busy, we give up */
-	if (timeout >= MAX_TIMEOUT) {
+	if (timeout == MAX_TIMEOUT) {
 		result = -ETIMEDOUT;
 		dev_err(&vt596_adapter.dev, "SMBus timeout!\n");
 	}

  parent reply	other threads:[~2010-01-05 21:22 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-12-27 14:49 [PATCH] i2c: test off by one in {piix4,vt596}_transaction() Roel Kluin
     [not found] ` <4B3773F2.3010703-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2010-01-05 16:55   ` Jean Delvare
     [not found]     ` <20100105175511.39dc6c42-ig7AzVSIIG7kN2dkZ6Wm7A@public.gmane.org>
2010-01-05 21:22       ` Roel Kluin [this message]
     [not found]         ` <4B43AD8F.2030809-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2010-01-06 11:14           ` Jean Delvare

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