Hi Wolfram Sang, Thank you very much for your review and kindly suggestions, would you please see my comments below: Best Regards, Yi Zeng +86-21-60336588 ext. 8686 -----Original Message----- From: Wolfram Sang [mailto:wsa@xxxxxxxxxxxxx] Sent: Friday, January 04, 2019 3:30 AM To: Zeng Yi（曾毅） Cc: linux-i2c@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx Subject: Re: [PATCH] i2c: dev: prevent adapter retries being set as minus value Hi Yi Zeng, On Fri, Dec 21, 2018 at 05:32:06PM +0800, Yi Zeng wrote: > If set adapter->retries to minus value from user space via ioctl, will > make __i2c_transfer and __i2c_smbus_xfer jump the calling to > adapter->algo->master_xfer and adapter->algo->smbus_xfer that > registered by the underlying bus drivers, and return value 0 to all > the callers. The bus driver will never be accessed anymore by all > users, besides, the users may still get successful return value with > no any error or information log print out. >> Thanks! The issue you observed is correct. It also applies to I2C_TIMEOUT. Would you mind fixing it there as well? Yes, I am very glad to do this fix. I will add the changes to the previous patch. > Signed-off-by: Yi Zeng <yizeng@xxxxxxxxxxxx> > --- > drivers/i2c/i2c-dev.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c index > 1aca742..c349f58 100644 > --- a/drivers/i2c/i2c-dev.c > +++ b/drivers/i2c/i2c-dev.c > @@ -470,6 +470,14 @@ static long i2cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) > data_arg.data); > } > case I2C_RETRIES: > + /* > + * The adapter->retries is defined as int type, and as > + * the upper limit for times of i2c transfer retry when > + * get -EAGAIN, it should not be set as minus value. > + */ >> I usually like comments explaining the situiation. However, here I think it is pretty clear that the code does just sanity checks. So, I think we can drop it. Thank you, I will drop it in the updates. > + if ((int)arg < 0) > + return -EINVAL; >> Minor nit: I'd think this is a little more readable >> if (arg > INT_MAX) >> return -EINVAL >> But I have no strong opinion here. Thank you very much for your suggestion, I think this is much better than the previous. Kind regards, Wolfram
