Re: [PATCH v10] i2c: virtio: add a virtio i2c frontend driver
From: Jie Deng <hidden>
Date: 2021-03-24 04:01:32
Also in:
linux-i2c, lkml
On 2021/3/24 11:52, Viresh Kumar wrote:
On 24-03-21, 08:53, Jie Deng wrote:quoted
On 2021/3/23 17:38, Viresh Kumar wrote:quoted
On 23-03-21, 14:31, Viresh Kumar wrote:quoted
On 23-03-21, 22:19, Jie Deng wrote:quoted
+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);I think I may have found a possible bug here. This reinit_completion() must happen before we call virtio_i2c_send_reqs(). It is certainly possible (surely in corner cases) that virtio_i2c_msg_done() may get called right after virtio_i2c_send_reqs() and before we were able to call reinit_completion(). And in that case we will never see the completion happen at all.quoted
+ virtqueue_kick(vq);I may have misread this. Can the actually start before virtqueue_kick() is called ?I didn't write it properly here. I wanted to say, "Can the _transfer_ actually start before virtqueue_kick() is called ?"
It can't start until the virtqueue_kick() is called. Call virtqueue_kick then wait. _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization