tree c5ecbd4f0fb87422ec47bd20fe19343f675da7a8
parent bfeffd155283772bbe78c6a05dec7c0128ee500c
author Yi Zeng <yizeng@asrmicro.com> 1547019187 +0800
committer Wolfram Sang <wsa@the-dreams.de> 1547162095 +0100

i2c: dev: prevent adapter retries and timeout being set as minus value

If adapter->retries is set to a minus value from user space via ioctl,
it will make __i2c_transfer and __i2c_smbus_xfer skip the calling to
adapter->algo->master_xfer and adapter->algo->smbus_xfer that is
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 without any
error or information log print out.

If adapter->timeout is set to minus value from user space via ioctl,
it will make the retrying loop in __i2c_transfer and __i2c_smbus_xfer
always break after the the first try, due to the time_after always
returns true.

Signed-off-by: Yi Zeng <yizeng@asrmicro.com>
[wsa: minor grammar updates to commit message]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org