1 // SPDX-License-Identifier: GPL-2.0-only
47  * struct virtio_chan - per-instance transport information
56  * @sg: scatter gather list which is used to pack a request (protected?)
59  * We keep all per-channel information in a structure.
60  * This structure is allocated within the devices dev->mem space.
94 	return PAGE_SIZE - offset_in_page(data);  in rest_of_page()
98  * p9_virtio_close - reclaim resources of a channel
108 	struct virtio_chan *chan = client->trans;  in p9_virtio_close()
112 		chan->inuse = false;  in p9_virtio_close()
117  * req_done - callback which signals activity from the server
121  * on the virtio channel - most likely a response to request we
131 	struct virtio_chan *chan = vq->vdev->priv;  in req_done()
139 	spin_lock_irqsave(&chan->lock, flags);  in req_done()
140 	while ((req = virtqueue_get_buf(chan->vq, &len)) != NULL) {  in req_done()
141 		if (!chan->ring_bufs_avail) {  in req_done()
142 			chan->ring_bufs_avail = 1;  in req_done()
147 			req->rc.size = len;  in req_done()
148 			p9_client_cb(chan->client, req, REQ_STATUS_RCVD);  in req_done()
151 	spin_unlock_irqrestore(&chan->lock, flags);  in req_done()
154 		wake_up(chan->vc_wq);  in req_done()
158  * pack_sg_list - pack a scatter gather list from a linear buffer
159  * @sg: scatter/gather list to pack into
162  * @data: data to pack into scatter/gather list
163  * @count: amount of data to pack into the scatter/gather list
166  * arbitrary data into an existing scatter gather list, segmenting the
185 		count -= s;  in pack_sg_list()
188 	if (index-start)  in pack_sg_list()
189 		sg_mark_end(&sg[index - 1]);  in pack_sg_list()
190 	return index-start;  in pack_sg_list()
207  * pack_sg_list_p - Just like pack_sg_list. Instead of taking a buffer,
209  * @sg: scatter/gather list to pack into
213  * @nr_pages: number of pages to pack into the scatter/gather list
215  * @count: amount of data to pack into the scatter/gather list
225 	BUG_ON(nr_pages > (limit - start));  in pack_sg_list_p()
231 		s = PAGE_SIZE - data_off;  in pack_sg_list_p()
239 		count -= s;  in pack_sg_list_p()
240 		nr_pages--;  in pack_sg_list_p()
243 	if (index-start)  in pack_sg_list_p()
244 		sg_mark_end(&sg[index - 1]);  in pack_sg_list_p()
245 	return index - start;  in pack_sg_list_p()
249  * p9_virtio_request - issue a request
261 	struct virtio_chan *chan = client->trans;  in p9_virtio_request()
266 	req->status = REQ_STATUS_SENT;  in p9_virtio_request()
268 	spin_lock_irqsave(&chan->lock, flags);  in p9_virtio_request()
272 	out = pack_sg_list(chan->sg, 0,  in p9_virtio_request()
273 			   VIRTQUEUE_NUM, req->tc.sdata, req->tc.size);  in p9_virtio_request()
275 		sgs[out_sgs++] = chan->sg;  in p9_virtio_request()
277 	in = pack_sg_list(chan->sg, out,  in p9_virtio_request()
278 			  VIRTQUEUE_NUM, req->rc.sdata, req->rc.capacity);  in p9_virtio_request()
280 		sgs[out_sgs + in_sgs++] = chan->sg + out;  in p9_virtio_request()
282 	err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req,  in p9_virtio_request()
285 		if (err == -ENOSPC) {  in p9_virtio_request()
286 			chan->ring_bufs_avail = 0;  in p9_virtio_request()
287 			spin_unlock_irqrestore(&chan->lock, flags);  in p9_virtio_request()
288 			err = wait_event_killable(*chan->vc_wq,  in p9_virtio_request()
289 						  chan->ring_bufs_avail);  in p9_virtio_request()
290 			if (err  == -ERESTARTSYS)  in p9_virtio_request()
296 			spin_unlock_irqrestore(&chan->lock, flags);  in p9_virtio_request()
299 			return -EIO;  in p9_virtio_request()
302 	virtqueue_kick(chan->vq);  in p9_virtio_request()
303 	spin_unlock_irqrestore(&chan->lock, flags);  in p9_virtio_request()
328 		if (atomic_read(&vp_pinned) >= chan->p9_max_pages) {  in p9_get_mapped_pages()
330 			      (atomic_read(&vp_pinned) < chan->p9_max_pages));  in p9_get_mapped_pages()
331 			if (err == -ERESTARTSYS)  in p9_get_mapped_pages()
347 		/* we'd already checked that it's non-empty */  in p9_get_mapped_pages()
351 				p = data->kvec->iov_base + data->iov_offset;  in p9_get_mapped_pages()
359 		nr_pages = DIV_ROUND_UP((unsigned long)p + len, PAGE_SIZE) -  in p9_get_mapped_pages()
365 			return -ENOMEM;  in p9_get_mapped_pages()
368 		p -= (*offs = offset_in_page(p));  in p9_get_mapped_pages()
381  * p9_virtio_zc_request - issue a zero copy request
400 	struct virtio_chan *chan = client->trans;  in p9_virtio_zc_request()
419 			memcpy(&req->tc.sdata[req->tc.size - 4], &v, 4);  in p9_virtio_zc_request()
426 		sz = cpu_to_le32(req->tc.size + outlen);  in p9_virtio_zc_request()
427 		memcpy(&req->tc.sdata[0], &sz, sizeof(sz));  in p9_virtio_zc_request()
438 			memcpy(&req->tc.sdata[req->tc.size - 4], &v, 4);  in p9_virtio_zc_request()
442 	req->status = REQ_STATUS_SENT;  in p9_virtio_zc_request()
444 	spin_lock_irqsave(&chan->lock, flags);  in p9_virtio_zc_request()
449 	out = pack_sg_list(chan->sg, 0,  in p9_virtio_zc_request()
450 			   VIRTQUEUE_NUM, req->tc.sdata, req->tc.size);  in p9_virtio_zc_request()
453 		sgs[out_sgs++] = chan->sg;  in p9_virtio_zc_request()
456 		sgs[out_sgs++] = chan->sg + out;  in p9_virtio_zc_request()
457 		out += pack_sg_list_p(chan->sg, out, VIRTQUEUE_NUM,  in p9_virtio_zc_request()
468 	in = pack_sg_list(chan->sg, out,  in p9_virtio_zc_request()
469 			  VIRTQUEUE_NUM, req->rc.sdata, in_hdr_len);  in p9_virtio_zc_request()
471 		sgs[out_sgs + in_sgs++] = chan->sg + out;  in p9_virtio_zc_request()
474 		sgs[out_sgs + in_sgs++] = chan->sg + out + in;  in p9_virtio_zc_request()
475 		in += pack_sg_list_p(chan->sg, out + in, VIRTQUEUE_NUM,  in p9_virtio_zc_request()
480 	err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req,  in p9_virtio_zc_request()
483 		if (err == -ENOSPC) {  in p9_virtio_zc_request()
484 			chan->ring_bufs_avail = 0;  in p9_virtio_zc_request()
485 			spin_unlock_irqrestore(&chan->lock, flags);  in p9_virtio_zc_request()
486 			err = wait_event_killable(*chan->vc_wq,  in p9_virtio_zc_request()
487 						  chan->ring_bufs_avail);  in p9_virtio_zc_request()
488 			if (err  == -ERESTARTSYS)  in p9_virtio_zc_request()
494 			spin_unlock_irqrestore(&chan->lock, flags);  in p9_virtio_zc_request()
497 			err = -EIO;  in p9_virtio_zc_request()
501 	virtqueue_kick(chan->vq);  in p9_virtio_zc_request()
502 	spin_unlock_irqrestore(&chan->lock, flags);  in p9_virtio_zc_request()
505 	err = wait_event_killable(req->wq, req->status >= REQ_STATUS_RCVD);  in p9_virtio_zc_request()
539 	chan = vdev->priv;  in p9_mount_tag_show()
540 	tag_len = strlen(chan->tag);  in p9_mount_tag_show()
542 	memcpy(buf, chan->tag, tag_len + 1);  in p9_mount_tag_show()
550  * p9_virtio_probe - probe for existence of 9P virtio channels
564 	if (!vdev->config->get) {  in p9_virtio_probe()
565 		dev_err(&vdev->dev, "%s failure: config access disabled\n",  in p9_virtio_probe()
567 		return -EINVAL;  in p9_virtio_probe()
573 		err = -ENOMEM;  in p9_virtio_probe()
577 	chan->vdev = vdev;  in p9_virtio_probe()
580 	chan->vq = virtio_find_single_vq(vdev, req_done, "requests");  in p9_virtio_probe()
581 	if (IS_ERR(chan->vq)) {  in p9_virtio_probe()
582 		err = PTR_ERR(chan->vq);  in p9_virtio_probe()
585 	chan->vq->vdev->priv = chan;  in p9_virtio_probe()
586 	spin_lock_init(&chan->lock);  in p9_virtio_probe()
588 	sg_init_table(chan->sg, VIRTQUEUE_NUM);  in p9_virtio_probe()
590 	chan->inuse = false;  in p9_virtio_probe()
594 		err = -EINVAL;  in p9_virtio_probe()
599 		err = -ENOMEM;  in p9_virtio_probe()
605 	chan->tag = tag;  in p9_virtio_probe()
606 	err = sysfs_create_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);  in p9_virtio_probe()
610 	chan->vc_wq = kmalloc(sizeof(wait_queue_head_t), GFP_KERNEL);  in p9_virtio_probe()
611 	if (!chan->vc_wq) {  in p9_virtio_probe()
612 		err = -ENOMEM;  in p9_virtio_probe()
615 	init_waitqueue_head(chan->vc_wq);  in p9_virtio_probe()
616 	chan->ring_bufs_avail = 1;  in p9_virtio_probe()
618 	chan->p9_max_pages = nr_free_buffer_pages()/4;  in p9_virtio_probe()
623 	list_add_tail(&chan->chan_list, &virtio_chan_list);  in p9_virtio_probe()
627 	kobject_uevent(&(vdev->dev.kobj), KOBJ_CHANGE);  in p9_virtio_probe()
632 	sysfs_remove_file(&vdev->dev.kobj, &dev_attr_mount_tag.attr);  in p9_virtio_probe()
636 	vdev->config->del_vqs(vdev);  in p9_virtio_probe()
645  * p9_virtio_create - allocate a new virtio channel
648  * @args: args passed from sys_mount() for per-transport options (unused)
662 	int ret = -ENOENT;  in p9_virtio_create()
666 		return -EINVAL;  in p9_virtio_create()
670 		if (!strcmp(devname, chan->tag)) {  in p9_virtio_create()
671 			if (!chan->inuse) {  in p9_virtio_create()
672 				chan->inuse = true;  in p9_virtio_create()
676 			ret = -EBUSY;  in p9_virtio_create()
686 	client->trans = (void *)chan;  in p9_virtio_create()
687 	client->status = Connected;  in p9_virtio_create()
688 	chan->client = client;  in p9_virtio_create()
694  * p9_virtio_remove - clean up resources associated with a virtio device
701 	struct virtio_chan *chan = vdev->priv;  in p9_virtio_remove()
707 	list_del(&chan->chan_list);  in p9_virtio_remove()
711 	while (chan->inuse) {  in p9_virtio_remove()
715 			dev_emerg(&vdev->dev,  in p9_virtio_remove()
724 	vdev->config->reset(vdev);  in p9_virtio_remove()
725 	vdev->config->del_vqs(vdev);  in p9_virtio_remove()
727 	sysfs_remove_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr);  in p9_virtio_remove()
728 	kobject_uevent(&(vdev->dev.kobj), KOBJ_CHANGE);  in p9_virtio_remove()
729 	kfree(chan->tag);  in p9_virtio_remove()
730 	kfree(chan->vc_wq);  in p9_virtio_remove()
769 	.maxsize = PAGE_SIZE * (VIRTQUEUE_NUM - 3),