ethtool: Expand documentation of struct ethtool_perm_addr

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 1 deletions

diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
index e96aec0bf7c1..79be416f03e6 100644
--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h
@@ -614,8 +614,19 @@ struct ethtool_stats {
         __u64   data[0];
 };
 
+/**
+ * struct ethtool_perm_addr - permanent hardware address
+ * @cmd: Command number = %ETHTOOL_GPERMADDR
+ * @size: On entry, the size of the buffer.  On return, the size of the
+ *      address.  The command fails if the buffer is too small.
+ * @data: Buffer for the address
+ *
+ * Users must allocate the buffer immediately following this structure.
+ * A buffer size of %MAX_ADDR_LEN should be sufficient for any address
+ * type.
+ */
 struct ethtool_perm_addr {
-        __u32   cmd;            /* ETHTOOL_GPERMADDR */
+        __u32   cmd;
         __u32   size;
         __u8    data[0];
 };