Messages in this thread Patch in this message | | | From | Zeng Yi(曾毅) <> | Subject | RE: [PATCH] i2c: dev: prevent adapter retries being set as minus value | Date | Mon, 7 Jan 2019 12:36:15 +0000 |
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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@the-dreams.de] Sent: Friday, January 04, 2019 3:30 AM To: Zeng Yi(曾毅) Cc: linux-i2c@vger.kernel.org; linux-kernel@vger.kernel.org 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@asrmicro.com> > --- > 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
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