On Thu, Dec 16, 2010 at 09:40:55AM +1100, Michael Ellerman wrote: > On Wed, 2010-12-15 at 10:35 -0800, Hollis Blanchard wrote: > > On Wed, Dec 8, 2010 at 7:09 PM, David Gibson > > <da...@gibson.dropbear.id.au> wrote: > > > On Thu, Dec 09, 2010 at 12:33:22PM +1100, Michael Ellerman wrote: > > >> On Wed, 2010-12-08 at 15:01 -0600, Scott Wood wrote: > > >> > On Wed, 8 Dec 2010 11:29:44 -0800 > > >> > Deepak Saxena <deepak_sax...@mentor.com> wrote: > > >> > > > >> > > We only return the next child if the device is available. > > >> > > > > >> > > Signed-off-by: Hollis Blanchard <hollis_blanch...@mentor.com> > > >> > > Signed-off-by: Deepak Saxena <deepak_sax...@mentor.com> > > >> > > --- > > >> > > drivers/of/base.c | 4 +++- > > >> > > 1 files changed, 3 insertions(+), 1 deletions(-) > > >> > > > > >> > > diff --git a/drivers/of/base.c b/drivers/of/base.c > > >> > > index 5d269a4..81b2601 100644 > > >> > > --- a/drivers/of/base.c > > >> > > +++ b/drivers/of/base.c > > >> > > @@ -321,6 +321,8 @@ struct device_node *of_get_next_parent(struct > > >> > > device_node *node) > > >> > > * > > >> > > * Returns a node pointer with refcount incremented, use > > >> > > * of_node_put() on it when done. > > >> > > + * > > >> > > + * Does not return nodes marked unavailable by a status > > >> > > property. > > >> > > */ > > >> > > struct device_node *of_get_next_child(const struct device_node > > >> > > *node, > > >> > > struct device_node *prev) > > >> > > @@ -330,7 +332,7 @@ struct device_node *of_get_next_child(const > > >> > > struct device_node *node, > > >> > > read_lock(&devtree_lock); > > >> > > next = prev ? prev->sibling : node->child; > > >> > > for (; next; next = next->sibling) > > >> > > - if (of_node_get(next)) > > >> > > + if (of_device_is_available(next) && of_node_get(next)) > > >> > > break; > > >> > > of_node_put(prev); > > >> > > read_unlock(&devtree_lock); > > >> > > > >> > This seems like too low-level a place to put this. Some code may know > > >> > how to un-disable a device in certain situations, or it may be part of > > >> > debug code trying to dump the whole device tree, etc. Looking > > >> > further[1], I see a raw version of this function, but not other things > > >> > like of_find_compatible_node. > > >> > > >> Yeah I agree. I think we'll eventually end up with __ versions of all or > > >> lots of them. Not to mention there might be cases you've missed where > > >> code expects to see unavailable nodes. The right approach is to add > > >> _new_ routines that don't return unavailable nodes, and convert code > > >> that you know wants to use them. > > > > > > Actually, I don't think we really want these status-skipping > > > iterators at all. The device tree iterators should give us the device > > > tree, as it is. Those old-style drivers which seach for a node rather > > > than using the bus probing logic can keep individual checks of the > > > status property until they're converted to the new scheme. > > > > So the patch should look something like this? > > > > @@ -321,6 +321,8 @@ struct device_node *of_get_next_parent(struct > > device_node *node) > > * > > * Returns a node pointer with refcount incremented, use > > * of_node_put() on it when done. > > + * > > + * Do not use this function. > > */ > > struct device_node *of_get_next_child(const struct device_node *node, > > struct device_node *prev) > > Haha. No it should say "this function doesn't lie to you". > > And the patch should say "this patch _doesn't_ subtly change all callers > of of_get_next_child() without carefully auditing them".
Heh, Yes. The comments made on this patch are totally on-base. Not all nodes are devices, and not all callers will want to skip nodes; regardless of the reason for skipping. Case in point: the /proc/device-tree support code. If a caller needs a version of the function that skips unavailable nodes, then that behaviour should be explicitly asked for. In this case it should be a new function with a new name. Don't change the behaviour out from under the existing users. g. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
