Re: [PATCH] i2c: test off by one in {piix4,vt596}_transaction()

From: Jean Delvare
Date: Wed Jan 06 2010 - 06:14:42 EST


On Tue, 05 Jan 2010 22:22:23 +0100, Roel Kluin wrote:
> 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@xxxxxxxxx>
> ---
> > 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");
> }

Applied, thanks.

--
Jean Delvare
--
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