xref: /dpdk/drivers/net/virtio/virtqueue.c (revision cdea34452b09f5ce3c2f3ada6182afa0071fce47)
1 /*-
2  *   BSD LICENSE
3  *
4  *   Copyright(c) 2010-2015 Intel Corporation. All rights reserved.
5  *   All rights reserved.
6  *
7  *   Redistribution and use in source and binary forms, with or without
8  *   modification, are permitted provided that the following conditions
9  *   are met:
10  *
11  *     * Redistributions of source code must retain the above copyright
12  *       notice, this list of conditions and the following disclaimer.
13  *     * Redistributions in binary form must reproduce the above copyright
14  *       notice, this list of conditions and the following disclaimer in
15  *       the documentation and/or other materials provided with the
16  *       distribution.
17  *     * Neither the name of Intel Corporation nor the names of its
18  *       contributors may be used to endorse or promote products derived
19  *       from this software without specific prior written permission.
20  *
21  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
24  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
25  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
31  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  */
33 #include <stdint.h>
34 
35 #include <rte_mbuf.h>
36 
37 #include "virtqueue.h"
38 #include "virtio_logs.h"
39 #include "virtio_pci.h"
40 
41 /*
42  * Two types of mbuf to be cleaned:
43  * 1) mbuf that has been consumed by backend but not used by virtio.
44  * 2) mbuf that hasn't been consued by backend.
45  */
46 struct rte_mbuf *
47 virtqueue_detatch_unused(struct virtqueue *vq)
48 {
49 	struct rte_mbuf *cookie;
50 	int idx;
51 
52 	if (vq != NULL)
53 		for (idx = 0; idx < vq->vq_nentries; idx++) {
54 			cookie = vq->vq_descx[idx].cookie;
55 			if (cookie != NULL) {
56 				vq->vq_descx[idx].cookie = NULL;
57 				return cookie;
58 			}
59 		}
60 	return NULL;
61 }
62 
63 /* Flush the elements in the used ring. */
64 void
65 virtqueue_flush(struct virtqueue *vq)
66 {
67 	struct vring_used_elem *uep;
68 	struct vq_desc_extra *dxp;
69 	uint16_t used_idx, desc_idx;
70 	uint16_t nb_used, i;
71 
72 	nb_used = VIRTQUEUE_NUSED(vq);
73 
74 	for (i = 0; i < nb_used; i++) {
75 		used_idx = vq->vq_used_cons_idx & (vq->vq_nentries - 1);
76 		uep = &vq->vq_ring.used->ring[used_idx];
77 		desc_idx = (uint16_t)uep->id;
78 		dxp = &vq->vq_descx[desc_idx];
79 		if (dxp->cookie != NULL) {
80 			rte_pktmbuf_free(dxp->cookie);
81 			dxp->cookie = NULL;
82 		}
83 		vq->vq_used_cons_idx++;
84 		vq_ring_free_chain(vq, desc_idx);
85 	}
86 }
87