drivers/net/virtio/virtqueue.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2015 Intel Corporation
   3  */
   4 #include <stdint.h>
   5
   6 #include <rte_mbuf.h>
   7
   8 #include "virtqueue.h"
   9 #include "virtio_logs.h"
  10 #include "virtio_pci.h"
  11
  12 /*
  13  * Two types of mbuf to be cleaned:
  14  * 1) mbuf that has been consumed by backend but not used by virtio.
  15  * 2) mbuf that hasn't been consued by backend.
  16  */
  17 struct rte_mbuf *
  18 virtqueue_detatch_unused(struct virtqueue *vq)
  19 {
  20         struct rte_mbuf *cookie;
  21         int idx;
  22
  23         if (vq != NULL)
  24                 for (idx = 0; idx < vq->vq_nentries; idx++) {
  25                         cookie = vq->vq_descx[idx].cookie;
  26                         if (cookie != NULL) {
  27                                 vq->vq_descx[idx].cookie = NULL;
  28                                 return cookie;
  29                         }
  30                 }
  31         return NULL;
  32 }
  33
  34 /* Flush the elements in the used ring. */
  35 void
  36 virtqueue_flush(struct virtqueue *vq)
  37 {
  38         struct vring_used_elem *uep;
  39         struct vq_desc_extra *dxp;
  40         uint16_t used_idx, desc_idx;
  41         uint16_t nb_used, i;
  42
  43         nb_used = VIRTQUEUE_NUSED(vq);
  44
  45         for (i = 0; i < nb_used; i++) {
  46                 used_idx = vq->vq_used_cons_idx & (vq->vq_nentries - 1);
  47                 uep = &vq->vq_ring.used->ring[used_idx];
  48                 desc_idx = (uint16_t)uep->id;
  49                 dxp = &vq->vq_descx[desc_idx];
  50                 if (dxp->cookie != NULL) {
  51                         rte_pktmbuf_free(dxp->cookie);
  52                         dxp->cookie = NULL;
  53                 }
  54                 vq->vq_used_cons_idx++;
  55                 vq_ring_free_chain(vq, desc_idx);
  56         }
  57 }