mbuf: add a function to linearize a packet

This patch adds function rte_pktmbuf_linearize to let crypto PMD coalesce
chained mbuf before crypto operation and extend their capabilities to
support segmented mbufs when device cannot handle them natively.

Included unit tests for rte_pktmbuf_linearize functionality:

 1) Creates banch of segmented mbufs with different size and number of
    segments.
 2) Fills noncontigouos mbuf with sequential values.
 3) Uses rte_pktmbuf_linearize to coalesce segmented buffer into one
    contiguous.
 4) Verifies data in linearized buffer.

Signed-off-by: Tomasz Kulasek <tomaszx.kulasek@intel.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>

diff --git a/app/test/test_mbuf.c b/app/test/test_mbuf.c
index c0823ea..a2e9bc6 100644 (file)
--- a/app/test/test_mbuf.c
+++ b/app/test/test_mbuf.c
@@ -930,6 +930,124 @@ test_failing_mbuf_sanity_check(void)
        return 0;
 }
 
+static int
+test_mbuf_linearize(int pkt_len, int nb_segs) {
+
+       struct rte_mbuf *m = NULL, *mbuf = NULL;
+       uint8_t *data;
+       int data_len = 0;
+       int remain;
+       int seg, seg_len;
+       int i;
+
+       if (pkt_len < 1) {
+               printf("Packet size must be 1 or more (is %d)\n", pkt_len);
+               return -1;
+       }
+
+       if (nb_segs < 1) {
+               printf("Number of segments must be 1 or more (is %d)\n",
+                               nb_segs);
+               return -1;
+       }
+
+       seg_len = pkt_len / nb_segs;
+       if (seg_len == 0)
+               seg_len = 1;
+
+       remain = pkt_len;
+
+       /* Create chained mbuf_src and fill it generated data */
+       for (seg = 0; remain > 0; seg++) {
+
+               m = rte_pktmbuf_alloc(pktmbuf_pool);
+               if (m == NULL) {
+                       printf("Cannot create segment for source mbuf");
+                       goto fail;
+               }
+
+               /* Make sure if tailroom is zeroed */
+               memset(rte_pktmbuf_mtod(m, uint8_t *), 0,
+                               rte_pktmbuf_tailroom(m));
+
+               data_len = remain;
+               if (data_len > seg_len)
+                       data_len = seg_len;
+
+               data = (uint8_t *)rte_pktmbuf_append(m, data_len);
+               if (data == NULL) {
+                       printf("Cannot append %d bytes to the mbuf\n",
+                                       data_len);
+                       goto fail;
+               }
+
+               for (i = 0; i < data_len; i++)
+                       data[i] = (seg * seg_len + i) % 0x0ff;
+
+               if (seg == 0)
+                       mbuf = m;
+               else
+                       rte_pktmbuf_chain(mbuf, m);
+
+               remain -= data_len;
+       }
+
+       /* Create destination buffer to store coalesced data */
+       if (rte_pktmbuf_linearize(mbuf)) {
+               printf("Mbuf linearization failed\n");
+               goto fail;
+       }
+
+       if (!rte_pktmbuf_is_contiguous(mbuf)) {
+               printf("Source buffer should be contiguous after "
+                               "linearization\n");
+               goto fail;
+       }
+
+       data = rte_pktmbuf_mtod(mbuf, uint8_t *);
+
+       for (i = 0; i < pkt_len; i++)
+               if (data[i] != (i % 0x0ff)) {
+                       printf("Incorrect data in linearized mbuf\n");
+                       goto fail;
+               }
+
+       rte_pktmbuf_free(mbuf);
+       return 0;
+
+fail:
+       if (mbuf)
+               rte_pktmbuf_free(mbuf);
+       return -1;
+}
+
+static int
+test_mbuf_linearize_check(void)
+{
+       struct test_mbuf_array {
+               int size;
+               int nb_segs;
+       } mbuf_array[] = {
+                       { 128, 1 },
+                       { 64, 64 },
+                       { 512, 10 },
+                       { 250, 11 },
+                       { 123, 8 },
+       };
+       unsigned int i;
+
+       printf("Test mbuf linearize API\n");
+
+       for (i = 0; i < RTE_DIM(mbuf_array); i++)
+               if (test_mbuf_linearize(mbuf_array[i].size,
+                               mbuf_array[i].nb_segs)) {
+                       printf("Test failed for %d, %d\n", mbuf_array[i].size,
+                                       mbuf_array[i].nb_segs);
+                       return -1;
+               }
+
+       return 0;
+}
 
 static int
 test_mbuf(void)
@@ -1023,6 +1141,11 @@ test_mbuf(void)
                printf("test_failing_mbuf_sanity_check() failed\n");
                return -1;
        }
+
+       if (test_mbuf_linearize_check() < 0) {
+               printf("test_mbuf_linearize_check() failed\n");
+               return -1;
+       }
        return 0;
 }
 

diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index ffbb4b3..bfce9f4 100644 (file)
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -1716,6 +1716,57 @@ rte_validate_tx_offload(const struct rte_mbuf *m)
        return 0;
 }
 
+/**
+ * Linearize data in mbuf.
+ *
+ * This function moves the mbuf data in the first segment if there is enough
+ * tailroom. The subsequent segments are unchained and freed.
+ *
+ * @param mbuf
+ *   mbuf to linearize
+ * @return
+ *   - 0, on success
+ *   - -1, on error
+ */
+static inline int
+rte_pktmbuf_linearize(struct rte_mbuf *mbuf)
+{
+       int seg_len, copy_len;
+       struct rte_mbuf *m;
+       struct rte_mbuf *m_next;
+       char *buffer;
+
+       if (rte_pktmbuf_is_contiguous(mbuf))
+               return 0;
+
+       /* Extend first segment to the total packet length */
+       copy_len = rte_pktmbuf_pkt_len(mbuf) - rte_pktmbuf_data_len(mbuf);
+
+       if (unlikely(copy_len > rte_pktmbuf_tailroom(mbuf)))
+               return -1;
+
+       buffer = rte_pktmbuf_mtod_offset(mbuf, char *, mbuf->data_len);
+       mbuf->data_len = (uint16_t)(mbuf->pkt_len);
+
+       /* Append data from next segments to the first one */
+       m = mbuf->next;
+       while (m != NULL) {
+               m_next = m->next;
+
+               seg_len = rte_pktmbuf_data_len(m);
+               rte_memcpy(buffer, rte_pktmbuf_mtod(m, char *), seg_len);
+               buffer += seg_len;
+
+               rte_pktmbuf_free_seg(m);
+               m = m_next;
+       }
+
+       mbuf->next = NULL;
+       mbuf->nb_segs = 1;
+
+       return 0;
+}
+
 /**
  * Dump an mbuf structure to a file.
  *