dpaa_eth: reduce data alignment requirements for the A050385 erratum

[linux-2.6-microblaze.git] / drivers / net / ethernet / freescale / dpaa / dpaa_eth.c

diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
index 4360ce4..2a2c7db 100644 (file)
--- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
+++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
@@ -2182,6 +2182,7 @@ static int dpaa_a050385_wa_xdpf(struct dpaa_priv *priv,
        struct xdp_frame *new_xdpf, *xdpf = *init_xdpf;
        void *new_buff;
        struct page *p;
+       int headroom;
 
        /* Check the data alignment and make sure the headroom is large
         * enough to store the xdpf backpointer. Use an aligned headroom
@@ -2191,25 +2192,40 @@ static int dpaa_a050385_wa_xdpf(struct dpaa_priv *priv,
         * byte frame headroom. If the XDP program uses all of it, copy the
         * data to a new buffer and make room for storing the backpointer.
         */
-       if (PTR_IS_ALIGNED(xdpf->data, DPAA_A050385_ALIGN) &&
+       if (PTR_IS_ALIGNED(xdpf->data, DPAA_FD_DATA_ALIGNMENT) &&
            xdpf->headroom >= priv->tx_headroom) {
                xdpf->headroom = priv->tx_headroom;
                return 0;
        }
 
+       /* The new xdp_frame is stored in the new buffer. Reserve enough space
+        * in the headroom for storing it along with the driver's private
+        * info. The headroom needs to be aligned to DPAA_FD_DATA_ALIGNMENT to
+        * guarantee the data's alignment in the buffer.
+        */
+       headroom = ALIGN(sizeof(*new_xdpf) + priv->tx_headroom,
+                        DPAA_FD_DATA_ALIGNMENT);
+
+       /* Assure the extended headroom and data don't overflow the buffer,
+        * while maintaining the mandatory tailroom.
+        */
+       if (headroom + xdpf->len > DPAA_BP_RAW_SIZE -
+                       SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
+               return -ENOMEM;
+
        p = dev_alloc_pages(0);
        if (unlikely(!p))
                return -ENOMEM;
 
        /* Copy the data to the new buffer at a properly aligned offset */
        new_buff = page_address(p);
-       memcpy(new_buff + priv->tx_headroom, xdpf->data, xdpf->len);
+       memcpy(new_buff + headroom, xdpf->data, xdpf->len);
 
        /* Create an XDP frame around the new buffer in a similar fashion
         * to xdp_convert_buff_to_frame.
         */
        new_xdpf = new_buff;
-       new_xdpf->data = new_buff + priv->tx_headroom;
+       new_xdpf->data = new_buff + headroom;
        new_xdpf->len = xdpf->len;
        new_xdpf->headroom = priv->tx_headroom;
        new_xdpf->frame_sz = DPAA_BP_RAW_SIZE;