net/9p: Add waitq to VirtIO transport.
If there is not enough space for the PDU on the VirtIO ring, current code returns -EIO propagating the error to user. This patch introduced a wqit_queue on the channel, and lets the process wait on this queue until VirtIO ring frees up. Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com> Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
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Родитель
419b39561e
Коммит
52f44e0d08
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@ -583,7 +583,8 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
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err = c->trans_mod->request(c, req);
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if (err < 0) {
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c->status = Disconnected;
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if (err != -ERESTARTSYS)
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c->status = Disconnected;
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goto reterr;
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}
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@ -75,6 +75,8 @@ struct virtio_chan {
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struct p9_client *client;
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struct virtio_device *vdev;
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struct virtqueue *vq;
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int ring_bufs_avail;
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wait_queue_head_t *vc_wq;
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/* Scatterlist: can be too big for stack. */
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struct scatterlist sg[VIRTQUEUE_NUM];
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@ -141,15 +143,21 @@ static void req_done(struct virtqueue *vq)
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do {
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spin_lock_irqsave(&chan->lock, flags);
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rc = virtqueue_get_buf(chan->vq, &len);
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spin_unlock_irqrestore(&chan->lock, flags);
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if (rc != NULL) {
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if (!chan->ring_bufs_avail) {
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chan->ring_bufs_avail = 1;
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wake_up(chan->vc_wq);
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}
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spin_unlock_irqrestore(&chan->lock, flags);
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P9_DPRINTK(P9_DEBUG_TRANS, ": rc %p\n", rc);
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P9_DPRINTK(P9_DEBUG_TRANS, ": lookup tag %d\n",
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rc->tag);
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req = p9_tag_lookup(chan->client, rc->tag);
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req->status = REQ_STATUS_RCVD;
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p9_client_cb(chan->client, req);
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} else {
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spin_unlock_irqrestore(&chan->lock, flags);
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}
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} while (rc != NULL);
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}
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@ -212,6 +220,7 @@ p9_virtio_request(struct p9_client *client, struct p9_req_t *req)
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P9_DPRINTK(P9_DEBUG_TRANS, "9p debug: virtio request\n");
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req_retry:
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req->status = REQ_STATUS_SENT;
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spin_lock_irqsave(&chan->lock, flags);
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@ -222,10 +231,23 @@ p9_virtio_request(struct p9_client *client, struct p9_req_t *req)
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err = virtqueue_add_buf(chan->vq, chan->sg, out, in, req->tc);
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if (err < 0) {
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spin_unlock_irqrestore(&chan->lock, flags);
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P9_DPRINTK(P9_DEBUG_TRANS,
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"9p debug: virtio rpc add_buf returned failure");
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return -EIO;
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if (err == -ENOSPC) {
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chan->ring_bufs_avail = 0;
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spin_unlock_irqrestore(&chan->lock, flags);
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err = wait_event_interruptible(*chan->vc_wq,
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chan->ring_bufs_avail);
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if (err == -ERESTARTSYS)
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return err;
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P9_DPRINTK(P9_DEBUG_TRANS, "9p:Retry virtio request\n");
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goto req_retry;
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} else {
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spin_unlock_irqrestore(&chan->lock, flags);
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P9_DPRINTK(P9_DEBUG_TRANS,
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"9p debug: "
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"virtio rpc add_buf returned failure");
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return -EIO;
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}
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}
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virtqueue_kick(chan->vq);
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@ -304,14 +326,23 @@ static int p9_virtio_probe(struct virtio_device *vdev)
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chan->tag_len = tag_len;
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err = sysfs_create_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
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if (err) {
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kfree(tag);
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goto out_free_vq;
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goto out_free_tag;
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}
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chan->vc_wq = kmalloc(sizeof(wait_queue_head_t), GFP_KERNEL);
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if (!chan->vc_wq) {
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err = -ENOMEM;
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goto out_free_tag;
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}
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init_waitqueue_head(chan->vc_wq);
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chan->ring_bufs_avail = 1;
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mutex_lock(&virtio_9p_lock);
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list_add_tail(&chan->chan_list, &virtio_chan_list);
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mutex_unlock(&virtio_9p_lock);
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return 0;
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out_free_tag:
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kfree(tag);
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out_free_vq:
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vdev->config->del_vqs(vdev);
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kfree(chan);
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@ -385,6 +416,7 @@ static void p9_virtio_remove(struct virtio_device *vdev)
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mutex_unlock(&virtio_9p_lock);
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sysfs_remove_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);
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kfree(chan->tag);
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kfree(chan->vc_wq);
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kfree(chan);
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}
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