vhost: calculate mbuf size

As a lib, we have no idea the app defined mbuf size.
This patch will calculate mbuf size dynamically.

Signed-off-by: Huawei Xie <huawei.xie@intel.com>
Acked-by: Changchun Ouyang <changchun.ouyang@intel.com>

diff --git a/lib/librte_vhost/vhost_rxtx.c b/lib/librte_vhost/vhost_rxtx.c
index 09f5cb8..d75ae02 100644 (file)
--- a/lib/librte_vhost/vhost_rxtx.c
+++ b/lib/librte_vhost/vhost_rxtx.c
@@ -526,8 +526,6 @@ virtio_dev_merge_tx(struct virtio_net *dev, struct rte_mempool *mbuf_pool, struc
        uint32_t i;
        uint16_t free_entries, entry_success = 0;
        uint16_t avail_idx;
-       uint32_t buf_size = MBUF_SIZE - (sizeof(struct rte_mbuf)
-                       + RTE_PKTMBUF_HEADROOM);
 
        vq = dev->virtqueue[VIRTIO_TXQ];
        avail_idx =  *((volatile uint16_t *)&vq->avail->idx);
@@ -591,12 +589,6 @@ virtio_dev_merge_tx(struct virtio_net *dev, struct rte_mempool *mbuf_pool, struc
 
                vb_offset = 0;
                vb_avail = desc->len;
-               seg_offset = 0;
-               seg_avail = buf_size;
-               cpy_len = RTE_MIN(vb_avail, seg_avail);
-
-               PRINT_PACKET(dev, (uintptr_t)vb_addr, desc->len, 0);
-
                /* Allocate an mbuf and populate the structure. */
                m = rte_pktmbuf_alloc(mbuf_pool);
                if (unlikely(m == NULL)) {
@@ -604,6 +596,11 @@ virtio_dev_merge_tx(struct virtio_net *dev, struct rte_mempool *mbuf_pool, struc
                                "Failed to allocate memory for mbuf.\n");
                        return entry_success;
                }
+               seg_offset = 0;
+               seg_avail = m->buf_len - RTE_PKTMBUF_HEADROOM;
+               cpy_len = RTE_MIN(vb_avail, seg_avail);
+
+               PRINT_PACKET(dev, (uintptr_t)vb_addr, desc->len, 0);
 
                seg_num++;
                cur = m;
@@ -640,7 +637,7 @@ virtio_dev_merge_tx(struct virtio_net *dev, struct rte_mempool *mbuf_pool, struc
                                prev->next = cur;
                                prev = cur;
                                seg_offset = 0;
-                               seg_avail = buf_size;
+                               seg_avail = cur->buf_len - RTE_PKTMBUF_HEADROOM;
                        } else {
                                if (desc->flags & VRING_DESC_F_NEXT) {
                                        /*
@@ -674,7 +671,7 @@ virtio_dev_merge_tx(struct virtio_net *dev, struct rte_mempool *mbuf_pool, struc
                                                prev->next = cur;
                                                prev = cur;
                                                seg_offset = 0;
-                                               seg_avail = buf_size;
+                                               seg_avail = cur->buf_len - RTE_PKTMBUF_HEADROOM;
                                        }
 
                                        desc = &vq->desc[desc->next];