From: Jie Deng <jie.deng@intel.com>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linux-i2c@vger.kernel.org,
virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org, wsa@kernel.org,
wsa+renesas@sang-engineering.com, mst@redhat.com, arnd@arndb.de,
jasowang@redhat.com, andriy.shevchenko@linux.intel.com,
yu1.wang@intel.com, shuo.a.liu@intel.com, conghui.chen@intel.com,
stefanha@redhat.com
Subject: Re: [PATCH v11] i2c: virtio: add a virtio i2c frontend driver
Date: Fri, 2 Jul 2021 11:36:45 +0800 [thread overview]
Message-ID: <34092cb2-03f9-231d-8769-4e45ed51c30f@intel.com> (raw)
In-Reply-To: <20210701061846.7u4zorimzpmb66v7@vireshk-i7>
On 2021/7/1 14:18, Viresh Kumar wrote:
> On 01-07-21, 14:10, Jie Deng wrote:
>> I think a fixed number of sgs will make things easier to develop backend.
> Yeah, but it looks awkward to send a message buffer which isn't used
> at all. From protocol's point of view, it just looks wrong/buggy.
>
> The backend can just look at the number of elements received, they
> can either be 2 (in case of zero-length) transfer, or 3 (for
> read/write) and any other number is invalid.
>
OK. Let's add the following two lines to make sure that msg_buf is only
sent when the msgs len is not zero. And backend judges whether it is
a zero-length request by checking the number of elements received.
+ if (msgs[i].len) {
reqs[i].buf = i2c_get_dma_safe_msg_buf(&msgs[i], 1);
if (!reqs[i].buf)
break;
sg_init_one(&msg_buf, reqs[i].buf, msgs[i].len);
if (msgs[i].flags & I2C_M_RD)
sgs[outcnt + incnt++] = &msg_buf;
else
sgs[outcnt++] = &msg_buf;
+}
next prev parent reply other threads:[~2021-07-02 3:36 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-01 3:24 [PATCH v11] i2c: virtio: add a virtio i2c frontend driver Jie Deng
2021-07-01 4:04 ` Viresh Kumar
2021-07-01 6:10 ` Jie Deng
2021-07-01 6:18 ` Viresh Kumar
2021-07-02 3:36 ` Jie Deng [this message]
2021-07-02 4:56 ` Viresh Kumar
2021-07-01 19:24 ` Wolfram Sang
2021-07-02 4:55 ` Viresh Kumar
2021-07-02 6:22 ` Wolfram Sang
2021-07-02 6:52 ` Jie Deng
2021-07-02 6:56 ` Viresh Kumar
2021-07-02 7:11 ` Wolfram Sang
2021-07-02 7:15 ` Jie Deng
2021-07-02 7:21 ` Viresh Kumar
2021-07-02 7:36 ` Wolfram Sang
2021-07-01 8:50 ` kernel test robot
2021-07-01 10:00 ` kernel test robot
2021-07-02 3:12 ` Jie Deng
2021-07-02 6:38 ` [kbuild-all] " Rong Chen
2021-07-01 10:45 ` Andy Shevchenko
2021-07-02 1:05 ` Jie Deng
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