Re: [PATCH v2 2/2] i2c: core-smbus: fix a potential missing-check bug

[Wolfram Sang]

On Sat, May 05, 2018 at 08:02:21AM -0500, Wenwen Wang wrote:
> In i2c_smbus_xfer_emulated(), the function i2c_transfer() is invoked to
> transfer i2c messages. The number of actual transferred messages is
> returned and saved to 'status'. If 'status' is negative, that means an
> error occurred during the transfer process. In that case, the value of
> 'status' is an error code to indicate the reason of the transfer failure.
> In most cases, i2c_transfer() can transfer 'num' messages with no error.
> And so 'status' == 'num'. However, due to unexpected errors, it is probable
> that only partial messages are transferred by i2c_transfer(). As a result,
> 'status' != 'num'. This special case is not checked after the invocation of
> i2c_transfer() and can potentially lead to unexpected issues in the
> following execution since it is expected that 'status' == 'num'.
> 
> This patch checks the return value of i2c_transfer() and returns an error
> code -EIO if the number of actual transferred messages 'status' is not
> equal to 'num'.
> 
> Signed-off-by: Wenwen Wang <wang6495@xxxxxxx>

Applied to for-current, thanks!

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