[PATCH] Fix powerpc vio_find_name to not use devices_subsys

[PATCH] Fix powerpc vio_find_name to not use devices_subsys

[Paul Mackerras]

This fixes vio_find_name() in arch/powerpc/kernel/vio.c, which is
currently broken because it tries to use devices_subsys.  That is bad
for two reasons: (1) it's doing (or trying to do) a scan of all
devices when it should only be scanning those on the vio bus, and
(2) devices_subsys was an internal symbol of the device system code
which was never meant for external use and has now gone away, and
thus the kernel fails to compile on pSeries.

The new version uses bus_find_device() on the vio bus (vio_bus_type).

Signed-off-by: Paul Mackerras <paulus@samba.org>
---
Greg, do you want to send this to Linus or will I do that?  Or do you
have a better version? :)

diff --git a/arch/powerpc/kernel/vio.c b/arch/powerpc/kernel/vio.c
index 19a5656..b179b7e 100644
--- a/arch/powerpc/kernel/vio.c
+++ b/arch/powerpc/kernel/vio.c
@@ -37,8 +37,6 @@
 #include <asm/iseries/hv_call_xm.h>
 #include <asm/iseries/iommu.h>
 
-extern struct kset devices_subsys; /* needed for vio_find_name() */
-
 static struct bus_type vio_bus_type;
 
 static struct vio_dev vio_bus_device  = { /* fake "parent" device */
@@ -361,19 +359,23 @@ EXPORT_SYMBOL(vio_get_attribute);
 #ifdef CONFIG_PPC_PSERIES
 /* vio_find_name() - internal because only vio.c knows how we formatted the
  * kobject name
- * XXX once vio_bus_type.devices is actually used as a kset in
- * drivers/base/bus.c, this function should be removed in favor of
- * "device_find(kobj_name, &vio_bus_type)"
  */
-static struct vio_dev *vio_find_name(const char *kobj_name)
+static int name_cmp(struct device *dev, void *data)
+{
+	const char *name = data;
+
+	return !strcmp(name, dev->bus_id);
+}
+
+static struct vio_dev *vio_find_name(const char *name)
 {
-	struct kobject *found;
+	struct device *found;
 
-	found = kset_find_obj(&devices_subsys, kobj_name);
+	found = bus_find_device(&vio_bus_type, NULL, (void *)name, name_cmp);
 	if (!found)
 		return NULL;
 
-	return to_vio_dev(container_of(found, struct device, kobj));
+	return to_vio_dev(found);
 }
 
 /**

Re: [PATCH] Fix powerpc vio_find_name to not use devices_subsys

[Greg KH]

On Sun, Jan 27, 2008 at 11:45:30AM +1100, Paul Mackerras wrote:
> This fixes vio_find_name() in arch/powerpc/kernel/vio.c, which is
> currently broken because it tries to use devices_subsys.  That is bad
> for two reasons: (1) it's doing (or trying to do) a scan of all
> devices when it should only be scanning those on the vio bus, and
> (2) devices_subsys was an internal symbol of the device system code
> which was never meant for external use and has now gone away, and
> thus the kernel fails to compile on pSeries.
> 
> The new version uses bus_find_device() on the vio bus (vio_bus_type).
> 
> Signed-off-by: Paul Mackerras <paulus@samba.org>
> ---
> Greg, do you want to send this to Linus or will I do that?  Or do you
> have a better version? :)

I'll send it to him, with a minor change (I'm going to make this a core
function, as others also use the same functionality, no need for
everyone to re-invent the wheel all the time.

I also have some other patches to send him to fix up the fall-out of
these driver core changes :)

thanks,

greg k-h