On 6/29/2018 1:17 PM, Rafal Kozik wrote:

From: Kozik <redacted>

Write combining (WC) increases NIC performance by making better
utilization of PCI bus, but cannot be use by all PMD.

To get internal_addr memory need to be mapped. But as memory could not be
mapped twice: with and without WC it should be skipped for WC. [1]

To do not spoil other drivers that potentially could use internal_addr,
parameter wc_activate adds possibility to skip it for those PMDs,
that do not use it.

[1] https://www.kernel.org/doc/ols/2008/ols2008v2-pages-135-144.pdf
	section 5.3 and 5.4

Signed-off-by: Rafal Kozik <redacted>
Acked-by: Bruce Richardson <redacted>

Acked-by: Ferruh Yigit <redacted>

(I am still not able to confirm this is needed, but since the behavior change is
controlled by module param and internal_addr is not used at all, no need to
block the patch)