linux-kernel - [PATCH v2] powerpc: don't enable cpu hotplug on mpic-based pseries

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Date:	Tue, 9 Oct 2007 19:38:24 -0500
From:	Olof Johansson <olof@...om.net>
To:	Stephen Rothwell <sfr@...b.auug.org.au>
Cc:	Greg KH <greg@...ah.com>, Greg KH <gregkh@...e.de>,
	linux-kernel@...r.kernel.org,
	Chris Wedgwood <reviews@...cw.f00f.org>,
	linuxppc-dev@...abs.org, paulus@...ba.org, tgall.foo@...il.com,
	Thomas Gleixner <tglx@...utronix.de>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	stable@...nel.org
Subject: [PATCH v2] powerpc: don't enable cpu hotplug on mpic-based pseries

Don't allow cpu hotplug on systems lacking XICS interrupt controller,
since current code is hardcoded for it.


Signed-off-by: Olof Johansson <olof@...om.net>

---

On Wed, Oct 10, 2007 at 10:18:26AM +1000, Stephen Rothwell wrote:

> > +	struct device_node *np;
> > +	const char *typep;
> > +
> > +	for (np = NULL; (np = of_find_node_by_name(np,
> > +						   "interrupt-controller"));) {
> > +		typep = of_get_property(np, "compatible", NULL);
> > +		if (strstr(typep, "open-pic")) {
> > +			printk(KERN_INFO "CPU Hotplug not supported on "
> > +				"systems using MPIC\n");
> 
> You need an of_node_put(np) here.

Grmbl, you're right.

pseries_discover_pic() doesn't have one, that's where I took the above
logic from. So we're obviously already leaking device node references.

Still, no reason to make it worse.


-Olof

diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index 9711eb0..ae85fc0 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -252,6 +252,21 @@ static struct notifier_block pseries_smp_nb = {
 
 static int __init pseries_cpu_hotplug_init(void)
 {
+	struct device_node *np;
+	const char *typep;
+
+	for (np = NULL; (np = of_find_node_by_name(np,
+						   "interrupt-controller"));) {
+		typep = of_get_property(np, "compatible", NULL);
+		if (strstr(typep, "open-pic")) {
+			of_node_put(np);
+
+			printk(KERN_INFO "CPU Hotplug not supported on "
+				"systems using MPIC\n");
+			return 0;
+		}
+	}
+
 	rtas_stop_self_args.token = rtas_token("stop-self");
 	qcss_tok = rtas_token("query-cpu-stopped-state");
 
-
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