s390/qeth: indicate contiguous TX buffer elements

The TX path usually maps the full content of a page into a buffer
element. But there's specific skb layouts (ie. linearized TSO skbs)
where the HW header (1) requires a separate buffer element, and (2) is
page-contiguous with the packet data that's mapped into the next buffer
element.
Flag such buffer elements accordingly, so that HW can optimize its data
access for them.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 9c9a6edb5384800a17774f3aeba65088ab336d67..4d1d053eebb725f6983c24d12e8a06f81c3c26df 100644 (file)
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -4110,8 +4110,16 @@ static unsigned int qeth_fill_buffer(struct qeth_qdio_out_buffer *buf,
                buffer->element[element].addr = virt_to_phys(hdr);
                buffer->element[element].length = hd_len;
                buffer->element[element].eflags = SBAL_EFLAGS_FIRST_FRAG;
-               /* remember to free cache-allocated HW header: */
-               buf->is_header[element] = ((void *)hdr != skb->data);
+
+               /* HW header is allocated from cache: */
+               if ((void *)hdr != skb->data)
+                       buf->is_header[element] = 1;
+               /* HW header was pushed and is contiguous with linear part: */
+               else if (length > 0 && !PAGE_ALIGNED(data) &&
+                        (data == (char *)hdr + hd_len))
+                       buffer->element[element].eflags |=
+                               SBAL_EFLAGS_CONTIGUOUS;
+
                element++;
        }