ethtool: avoid signed-unsigned comparison in ethtool_validate_speed()

michaelzhivich · davem330 · commit afe64245af9f · 2019-04-08T16:30:43.000-07:00
When building C++ userspace code that includes ethtool.h
with "-Werror -Wall", g++ complains about signed-unsigned comparison in
ethtool_validate_speed() due to definition of SPEED_UNKNOWN as -1.

Explicitly cast SPEED_UNKNOWN to __u32 to match type of
ethtool_validate_speed() argument.

Signed-off-by: Michael Zhivich &lt;mzhivich@akamai.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
@@ -1591,7 +1591,7 @@ enum ethtool_link_mode_bit_indices {
 
 static inline int ethtool_validate_speed(__u32 speed)
 {
-	return speed <= INT_MAX || speed == SPEED_UNKNOWN;
+	return speed <= INT_MAX || speed == (__u32)SPEED_UNKNOWN;
 }
 
 /* Duplex, half or full. */

Original file line number	Diff line number	Diff line change
`@@ -1591,7 +1591,7 @@ enum ethtool_link_mode_bit_indices {`
`1591`	`1591`
`1592`	`1592`	`static inline int ethtool_validate_speed(__u32 speed)`
`1593`	`1593`	`{`
`1594`		`- return speed <= INT_MAX \|\| speed == SPEED_UNKNOWN;`
	`1594`	`+ return speed <= INT_MAX \|\| speed == (__u32)SPEED_UNKNOWN;`
`1595`	`1595`	`}`
`1596`	`1596`
`1597`	`1597`	`/* Duplex, half or full. */`