From: Tadeusz Struk <tadeusz.struk@intel.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: jgg@ziepe.ca, linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 2/2] tpm: add support for partial reads
Date: Sun, 18 Nov 2018 19:05:19 -0800 [thread overview]
Message-ID: <90072f09-6388-b1f7-387b-42f056f8893d@intel.com> (raw)
In-Reply-To: <20181118074832.GG5897@linux.intel.com>
On 11/17/18 11:48 PM, Jarkko Sakkinen wrote:
>> + if (priv->transmit_result || priv->partial_data) {
>> + if (*off == 0)
>> + priv->partial_data = priv->transmit_result;
>> +
>> + ret_size = min_t(ssize_t, size, priv->partial_data);
>> + if (ret_size <= 0) {
> When ret_size < 0? Shouldn't this be just "if (!ret_size)"?
What we want to check here is if ret_size is positive, which is a valid
value, or if it is negative or zero, which is an invalid value, so in
this case (!ret_size) will not work.
>
>> /* Holds the resul of the last successful call to tpm_transmit() */
>> size_t transmit_result;
>> + /* Holds the count how much of the response is still unread */
>> + size_t partial_data;
> I'm otherwise happy how this look like but why call it partial_data.
> You cannot really tell from the name anything about its contents as
> data is very abstract term.
so I will rename these two to response_length and response_length_rem,
how does this sound?
> BTW, why you need the new variable anyway and not just decrease the
> variable where the length is original stored?
We need to have two variables, otherwise how do we tell if some part of
response was consumed to allow sending a new command?
The transmit_result is used for that. If it is zero then one can transmit
a new command even if the whole response is not consumed. The new variable
tracks how much of the response is still to be read.
Thanks,
--
Tadeusz
next prev parent reply other threads:[~2018-11-19 3:05 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-16 17:51 [PATCH 1/2] tpm: rename data_pending to transmit_result Tadeusz Struk
2018-11-16 17:51 ` [PATCH v4 2/2] tpm: add support for partial reads Tadeusz Struk
2018-11-18 7:48 ` Jarkko Sakkinen
2018-11-19 3:05 ` Tadeusz Struk [this message]
2018-11-19 13:58 ` Jarkko Sakkinen
2018-11-19 16:44 ` Tadeusz Struk
2018-11-19 17:28 ` Jarkko Sakkinen
2018-11-19 17:43 ` Tadeusz Struk
2018-11-18 7:41 ` [PATCH 1/2] tpm: rename data_pending to transmit_result Jarkko Sakkinen
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