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
