[UNIKRAFT/LWIP PATCH v4 4/5] netbuf: Aligned buffers with `lwip_alloc_netbuf()`

[Simon Kuenzer <simon.kuenzer@xxxxxxxxx>]

Adds an alignment parameter to `lwip_alloc_netbuf()`. The netbuf
buffer area (`m->buf`) will be aligned.

Signed-off-by: Simon Kuenzer <simon.kuenzer@xxxxxxxxx>
---
 netbuf.c   | 26 ++++++--------------------
 netbuf.h   |  2 +-
 uknetdev.c |  1 +
 3 files changed, 8 insertions(+), 21 deletions(-)

diff --git a/netbuf.c b/netbuf.c
index 4878f74..97c129c 100644
--- a/netbuf.c
+++ b/netbuf.c
@@ -50,32 +50,20 @@ static void _netbuf_free(struct pbuf *p)
 }
 
 struct uk_netbuf *lwip_alloc_netbuf(struct uk_alloc *a, size_t alloc_size,
-                                   size_t headroom)
+                                   size_t alloc_align, uint16_t headroom)
 {
-       void *allocation;
        struct uk_netbuf *b;
        struct _netbuf_pbuf *np;
 
-       allocation = uk_malloc(a, alloc_size);
-       if (unlikely(!allocation))
-               goto err_out;
-
-       b = uk_netbuf_prepare_buf(allocation, alloc_size,
-                                 headroom, sizeof(struct _netbuf_pbuf), NULL);
+       b = uk_netbuf_alloc_buf(a, alloc_size, alloc_align,
+                               headroom, sizeof(struct _netbuf_pbuf), NULL);
        if (unlikely(!b)) {
                LWIP_DEBUGF(PBUF_DEBUG,
-                           ("Failed to initialize netbuf with encapsulated 
pbuf: requested headroom: %"__PRIsz", alloc_size: %"__PRIsz"\n",
-                            headroom, alloc_size));
-               goto err_free_allocation;
+                           ("Failed to allocate netbuf with encapsulated pbuf: 
requested headroom: %"__PRIu16", size: %"__PRIsz", alignement: %"__PRIsz"\n",
+                            headroom, alloc_size, alloc_align));
+               goto err_out;
        }
 
-       /*
-        * Register allocator so that uk_netbuf_free() will
-        * return our memory back to this allocator when free'ing
-        * this netbuf
-        */
-       b->_a = a;
-
        /* Fill-out meta data */
        np = (struct _netbuf_pbuf *) uk_netbuf_get_priv(b);
        memset(np, 0, sizeof(struct _netbuf_pbuf));
@@ -97,8 +85,6 @@ struct uk_netbuf *lwip_alloc_netbuf(struct uk_alloc *a, 
size_t alloc_size,
                     b, b->buflen, uk_netbuf_headroom(b)));
        return b;
 
-err_free_allocation:
-       uk_free(a, allocation);
 err_out:
        return NULL;
 }
diff --git a/netbuf.h b/netbuf.h
index 1492065..db5adf7 100644
--- a/netbuf.h
+++ b/netbuf.h
@@ -61,7 +61,7 @@ struct _netbuf_pbuf {
  * before handing over the embedded pbuf to the network stack.
  */
 struct uk_netbuf *lwip_alloc_netbuf(struct uk_alloc *a, size_t alloc_size,
-                                   size_t headroom);
+                                   size_t alloc_align, uint16_t headroom);
 
 /**
  * Returns the reference of the embedded pbuf of a netbuf
diff --git a/uknetdev.c b/uknetdev.c
index ba7d41c..7b689f9 100644
--- a/uknetdev.c
+++ b/uknetdev.c
@@ -99,6 +99,7 @@ static uint16_t netif_alloc_rxpkts(void *argp, struct 
uk_netbuf *nb[],
        for (i = 0; i < count; ++i) {
                nb[i] = lwip_alloc_netbuf(lwip_data->pkt_a,
                                          UKNETDEV_BUFLEN,
+                                         1,
                                          lwip_data->rx_headroom);
                if (!nb[i]) {
                        /* we run out of memory */
-- 
2.20.1