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? > 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. > + 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. Kind regards, Wolfram
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