Re: [PATCH next 3/3] ipvlan: Introduce l3s mode

On Sat, Sep 10, 2016 at 11:11 AM, David Miller [off-list ref] wrote:

From: David Ahern <redacted>
Date: Sat, 10 Sep 2016 10:25:27 -0600

quoted

On 9/9/16 4:46 PM, Mahesh Bandewar (महेश बंडेवार) wrote:

quoted

On Fri, Sep 9, 2016 at 3:26 PM, David Ahern [off-list ref] wrote:

quoted

On 9/9/16 3:53 PM, Mahesh Bandewar wrote:

quoted

diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 0c5415b05ea9..95edd1737ab5 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig

@@ -149,6 +149,7 @@ config IPVLAN
     tristate "IP-VLAN support"
     depends on INET
     depends on IPV6
+    select NET_L3_MASTER_DEV

depends on instead of select?

The kbuild/kconfig-language.txt suggests that for "depends on" the
option _must_ be selected otherwise menuconfig wont even present the
dependent option while select positively sets the option.

understood. VRF driver uses 'depends on'

Select is for things that are largely invisible to the user.  It is more of
a brute force tool that has several limitations.  For one, it doesn't
recursively apply dependencies of the thing you selected.  This makes it
quite trivial to create situations where you select X but it actually
can't work because it's "depend" statements aren't satisfied.

I look at "select" as more of a tool than brute-force / hack. It
allows to "select" something that is largely independent and otherwise
not really harmful (of for that matter even useful). Now if you look
at L3_MASTER, it's not really useful if the users of this feature (VRF
or IPvlan) are not chosen. Hence I would say "select" fits in this
scenario better (I mean for IPvlan or VRF driver choosing select over
depend) However I agree that if you "select" some option which has
dependencies and it becomes ambiguous but that's not the case here.

Depend is really the thing you ought to use, and yes this means that the
user has to know to enable the thing you depend upon to make your feature
available.  But that's just how it works.

I thought "select" is a better choice for the said reasons. I don't
mind changing it to "depend" but it would make it difficult for novice
users to figure-out why they can't see this driver-config.