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s390/qeth: indicate contiguous TX buffer elements

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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>
This commit is contained in:
Julian Wiedmann 2020-05-06 10:09:46 +02:00 committed by David S. Miller
parent fff1aceb88
commit a875fd1620
1 changed files with 10 additions and 2 deletions
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12
drivers/s390/net/qeth_core_main.c
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@ -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++;
}