Re: [PATCH] kexec: Export kexec_in_progress to modules

On 10/21/2016 11:37 AM, Eric W. Biederman wrote:

David Miller [off-list ref] writes:

quoted

From: ebiederm@xmission.com (Eric W. Biederman)
Date: Fri, 21 Oct 2016 00:26:55 -0500

quoted

So as far as I can tell you are advocating for a change to support a
driver doing something that is completely pointless.  So no let's not
export this symbol.  Please fix the driver to do something less
pointless instead.

FLorian explained his reasoning for doing what he is doing in this
specific driver and it made sense to me.

What doesn't make sense to me is not doing that for any other kind of
reboot.

Of the 3 uses of kexec_in_progres in the kernel (not counting this one)
I think there is only one of them that is really valid.   And that one
is only valid because it is the least horrible thing the pci layer can
do.  (AKA it is a hack even there).

It really is nonsense having methods do different things depending on
context and that is why kexec_in_progress is not exeported.

As far as I can tell the use of kexec_in_progress winds up being
a fragile hack that will just cause more problems later on.

Florian is there a good readon why you don't just do?

Checking kexec_in_progress allowed not to turn the PHY on for a normal
reboot case, since we don't necessarily know when it will be
re-initialized next, so in that sense it's a power optimization that is
nice to have.

static void bcm_sf2_sw_shutdown(struct platform_device *pdev)
{
        struct bcm_sf2_priv *priv = platform_get_drvdata(pdev);

	/* For a kernel about to be kexec'd we want to keep the GPHY on for a
         * successful MDIO bus scan to occur. If we did turn off the GPHY
	 * before (e.g: port_disable), this will also power it back on.
	 */
	if (priv->hw_params.num_gphy == 1)
		bcm_sf2_gphy_enable_set(priv->dev->ds, true);
}

I certainly don't see anything in the changelog to explain why that
isn't done.

That would result in an identical behavior for what I am after, David,
shall I send a revert plus this?
-- 
Florian