From: Viresh Kumar <viresh.kumar@linaro.org>
To: Jie Deng <jie.deng@intel.com>
Cc: linux-i2c@vger.kernel.org,
virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org, mst@redhat.com, wsa@kernel.org,
jasowang@redhat.com, wsa+renesas@sang-engineering.com,
andriy.shevchenko@linux.intel.com, conghui.chen@intel.com,
arnd@arndb.de, kblaiech@mellanox.com,
jarkko.nikula@linux.intel.com, Sergey.Semin@baikalelectronics.ru,
rppt@kernel.org, loic.poulain@linaro.org, tali.perry1@gmail.com,
u.kleine-koenig@pengutronix.de, bjorn.andersson@linaro.org,
yu1.wang@intel.com, shuo.a.liu@intel.com, stefanha@redhat.com,
pbonzini@redhat.com
Subject: Re: [PATCH v8] i2c: virtio: add a virtio i2c frontend driver
Date: Fri, 19 Mar 2021 11:23:22 +0530 [thread overview]
Message-ID: <20210319055322.lw4dhb2kwtrtd3qu@vireshk-i7> (raw)
In-Reply-To: <c193b92d8d22ba439bb1b260d26d4b76f57d4840.1615889867.git.jie.deng@intel.com>
On 16-03-21, 18:35, Jie Deng wrote:
> +++ b/drivers/i2c/busses/i2c-virtio.c
> +static int virtio_i2c_send_reqs(struct virtqueue *vq,
> + struct virtio_i2c_req *reqs,
> + struct i2c_msg *msgs, int nr)
> +{
> + struct scatterlist *sgs[3], out_hdr, msg_buf, in_hdr;
> + int i, outcnt, incnt, err = 0;
> +
> + for (i = 0; i < nr; i++) {
> + if (!msgs[i].len)
> + break;
> +
> + /*
> + * Only 7-bit mode supported for this moment. For the address format,
> + * Please check the Virtio I2C Specification.
> + */
> + reqs[i].out_hdr.addr = cpu_to_le16(msgs[i].addr << 1);
> +
> + if (i != nr - 1)
> + reqs[i].out_hdr.flags = cpu_to_le32(VIRTIO_I2C_FLAGS_FAIL_NEXT);
> +
> + outcnt = incnt = 0;
> + sg_init_one(&out_hdr, &reqs[i].out_hdr, sizeof(reqs[i].out_hdr));
> + sgs[outcnt++] = &out_hdr;
> +
> + reqs[i].buf = i2c_get_dma_safe_msg_buf(&msgs[i], 1);
You allocate a buffer here, lets see if they are freeing properly or not (I
remember that I gave same feedback earlier as well, but anyway).
> + 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;
> +
> + sg_init_one(&in_hdr, &reqs[i].in_hdr, sizeof(reqs[i].in_hdr));
> + sgs[outcnt + incnt++] = &in_hdr;
> +
> + err = virtqueue_add_sgs(vq, sgs, outcnt, incnt, &reqs[i], GFP_KERNEL);
> + if (err < 0) {
> + pr_err("failed to add msg[%d] to virtqueue.\n", i);
> + i2c_put_dma_safe_msg_buf(reqs[i].buf, &msgs[i], false);
On failure here, you freed the buffers for request "i" but not others..
> + break;
> + }
> + }
> +
> + return i;
> +}
> +
> +static int virtio_i2c_complete_reqs(struct virtqueue *vq,
> + struct virtio_i2c_req *reqs,
> + struct i2c_msg *msgs, int nr)
> +{
> + struct virtio_i2c_req *req;
> + unsigned int len;
> + int i, j;
> +
> + for (i = 0; i < nr; i++) {
> + req = virtqueue_get_buf(vq, &len);
> + if (!(req && req == &reqs[i])) {
> + pr_err("msg[%d]: addr=0x%x is out of order.\n", i, msgs[i].addr);
> + break;
Since you break here, what will happen to the buffer ? I thought
virtqueue_get_buf() will return a req only once and then you can't access it ?
> + }
> +
> + if (req->in_hdr.status != VIRTIO_I2C_MSG_OK) {
> + pr_err("msg[%d]: addr=0x%x backend error.\n", i, msgs[i].addr);
> + break;
> + }
> +
> + i2c_put_dma_safe_msg_buf(req->buf, &msgs[i], true);
> + }
> +
> + /*
> + * Detach all the used buffers from the vq and
> + * Release unused DMA safe buffer if any.
> + */
> + for (j = i; j < nr; j++) {
> + req = virtqueue_get_buf(vq, &len);
> + if (req)
> + i2c_put_dma_safe_msg_buf(req->buf, &msgs[j], false);
This will come in play only if something failed in the earlier loop ? Or my
understanding incorrect ? Also this should be merged with the above for loop
itself, it is just doing part of it.
> + }
> +
> + return i;
> +}
> +
> +static int virtio_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
> +{
> + struct virtio_i2c *vi = i2c_get_adapdata(adap);
> + struct virtqueue *vq = vi->vq;
> + struct virtio_i2c_req *reqs;
> + unsigned long time_left;
> + int ret, nr;
> +
> + reqs = kcalloc(num, sizeof(*reqs), GFP_KERNEL);
> + if (!reqs)
> + return -ENOMEM;
> +
> + mutex_lock(&vi->lock);
> +
> + ret = virtio_i2c_send_reqs(vq, reqs, msgs, num);
> + if (ret == 0)
> + goto err_unlock_free;
> +
> + nr = ret;
> + reinit_completion(&vi->completion);
> + virtqueue_kick(vq);
> +
> + time_left = wait_for_completion_timeout(&vi->completion, adap->timeout);
> + if (!time_left) {
On error here, we will surely not free the buffers, isn't it ?
> + dev_err(&adap->dev, "virtio i2c backend timeout.\n");
> + ret = -ETIMEDOUT;
> + goto err_unlock_free;
> + }
> +
> + ret = virtio_i2c_complete_reqs(vq, reqs, msgs, nr);
> +
> +err_unlock_free:
> + mutex_unlock(&vi->lock);
> + kfree(reqs);
> + return ret;
> +}
--
viresh
next prev parent reply other threads:[~2021-03-19 5:54 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-16 10:35 [PATCH v8] i2c: virtio: add a virtio i2c frontend driver Jie Deng
2021-03-16 7:44 ` Viresh Kumar
2021-03-18 14:40 ` Enrico Weigelt, metux IT consult
2021-03-18 14:52 ` Arnd Bergmann
2021-03-19 3:54 ` Viresh Kumar
2021-03-19 5:31 ` Jie Deng
2021-03-19 5:40 ` Viresh Kumar
2021-03-19 6:29 ` Jie Deng
2021-03-19 6:35 ` Viresh Kumar
2021-03-19 6:56 ` Jie Deng
2021-03-19 8:27 ` Arnd Bergmann
2021-03-16 7:53 ` Viresh Kumar
2021-03-19 5:53 ` Viresh Kumar [this message]
2021-03-19 7:52 ` Jie Deng
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210319055322.lw4dhb2kwtrtd3qu@vireshk-i7 \
--to=viresh.kumar@linaro.org \
--cc=Sergey.Semin@baikalelectronics.ru \
--cc=andriy.shevchenko@linux.intel.com \
--cc=arnd@arndb.de \
--cc=bjorn.andersson@linaro.org \
--cc=conghui.chen@intel.com \
--cc=jarkko.nikula@linux.intel.com \
--cc=jasowang@redhat.com \
--cc=jie.deng@intel.com \
--cc=kblaiech@mellanox.com \
--cc=linux-i2c@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=loic.poulain@linaro.org \
--cc=mst@redhat.com \
--cc=pbonzini@redhat.com \
--cc=rppt@kernel.org \
--cc=shuo.a.liu@intel.com \
--cc=stefanha@redhat.com \
--cc=tali.perry1@gmail.com \
--cc=u.kleine-koenig@pengutronix.de \
--cc=virtualization@lists.linux-foundation.org \
--cc=wsa+renesas@sang-engineering.com \
--cc=wsa@kernel.org \
--cc=yu1.wang@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).