[PATCH ethtool] ethtool: Fix the "advertise" parameter logic.

[Michael Chan <michael.chan@broadcom.com>]

From: Michael Chan <mchan@broadcom.com>

The current code ignores the value of the advertise parameter.  For example,

ethtool -s ethx advertise 0x1000

The full_advertising_wanted parameter of 0x1000 is not passed to the kernel.
The reason is that advertising_wanted is NULL in this case, and ethtool
will think that the user has given no advertisement input and so it will
proceed to pass all supported advertisement speeds to the kernel.

The older legacy ethtool with similar logic worked because
advertising_wanted was an integer and could take on -1 and 0.  It would pass
the full_advertising_wanted value if advertising_wanted == -1.

This fix is to pass all supported advertisement speeds only when both
advertising_wanted == NULL && full_advertising_wanted == NULL.

Signed-off-by: Michael Chan <michael.chan@broadcom.com>
---
 ethtool.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/ethtool.c b/ethtool.c
index 49ac94e..7715823 100644
--- a/ethtool.c
+++ b/ethtool.c
@@ -2971,7 +2971,8 @@ static int do_sset(struct cmd_context *ctx)
 				fprintf(stderr,	"\n");
 			}
 			if (autoneg_wanted == AUTONEG_ENABLE &&
-			    advertising_wanted == NULL) {
+			    advertising_wanted == NULL &&
+			    full_advertising_wanted == NULL) {
 				unsigned int i;
 
 				/* Auto negotiation enabled, but with
-- 
1.8.4.5