Re: [PATCH net-next] qdisc: propagate errors from qdisc_create_dflt

[David Miller <davem@davemloft.net>]

From: Stephen Hemminger <stephen@networkplumber.org>
Date: Sun, 17 Mar 2013 09:36:22 -0700

> This patch improves the error handling of default queuing discipline.
> 
> The function qdisc_create_dflt masks the error code from the underlying
> qdisc init function. Use IS_ERR() to propagate it back out to the callers.
> 
> Change the error handling of several qdisc's to report error rather than
> silently substituting a noop qdisc. Change the log level of failure to
> setup queue discipline from info to notice, since it is a real error.
> 
> In current kernel, the only likely error from pfifo_fast is out of memory,
> but the API shouldn't be hiding errors.
> 
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

If you're going to do this, you must change all the call sites so that
they don't leave error pointers in the various datastructures.

So code that does:

	foo->member = qdisc_create_dflt();

must now go:

	var = qdisc_create_dflt();
	if (IS_ERR(var))
		goto out_err;

	foo->member = var;