On Tue, 20 May 2014 19:41:22 -0700, Frank Rowand <frowand.list@xxxxxxxxx> wrote:
> On 5/18/2014 2:27 AM, Grant Likely wrote:
> > On Fri, 16 May 2014 11:54:44 +0100, Grant Likely <grant.likely@xxxxxxxxxx> wrote:
> >> On Thu, 15 May 2014 19:51:17 -0700, Frank Rowand <frowand.list@xxxxxxxxx> wrote:
> >>> On 5/13/2014 7:58 AM, Grant Likely wrote:
> >>>> Make of_find_node_by_path() handle aliases as prefixes. To make this
> >>>> work the name search is refactored to search by path component instead
> >>>> of by full string. This should be a more efficient search, and it makes
> >>>> it possible to start a search at a subnode of a tree.
> >>>>
> >>>> Signed-off-by: David Daney <david.daney@xxxxxxxxxx>
> >>>> Signed-off-by: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx>
> >>>> [grant.likely: Rework to not require allocating at runtime]
> >>>> Acked-by: Rob Herring <robh@xxxxxxxxxx>
> >>>> Signed-off-by: Grant Likely <grant.likely@xxxxxxxxxx>
> >>>> ---
> >>>> drivers/of/base.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++----
> >>>> 1 file changed, 56 insertions(+), 4 deletions(-)
> >>>>
> >>>> diff --git a/drivers/of/base.c b/drivers/of/base.c
> >>>> index 6e240698353b..60089b9a3014 100644
> >>>> --- a/drivers/of/base.c
> >>>> +++ b/drivers/of/base.c
> >>>> @@ -771,9 +771,38 @@ struct device_node *of_get_child_by_name(const struct device_node *node,
> >>>> }
> >>>> EXPORT_SYMBOL(of_get_child_by_name);
> >>>>
> >>>> +static struct device_node *__of_find_node_by_path(struct device_node *parent,
> >>>> + const char *path)
> >>>> +{
> >>>> + struct device_node *child;
> >>>> + int len = strchrnul(path, '/') - path;
> >>>> +
> >>>> + if (!len)
> >>>> + return parent;
> >>>
> >>> (!len) is true if the the final character of the path passed into of_find_node_by_path()
> >>> was "/". Strictly speaking, ->full_name will never end with "/", so the return value
> >>> should be NULL, indicating that the match fails.
> >>
> >> Ah, good catch. I should add a test case for that.
> >
> > In my testing this looks okay. The while loop that calls into
> > __of_find_node_by_path() looks like this:
> >
> > while (np && *path == '/') {
> > path++; /* Increment past '/' delimiter */
> > np = __of_find_node_by_path(np, path);
> > path = strchrnul(path, '/');
> > }
> >
> > If the path ends with a '/', then the loop will go around one more time.
> > The pointer will be incremented to point at the null character and len
> > will be null because strchrnul() will point at the last item.
>
> Yes, that was my point. The old version of of_find_node_by_path() would not
> find a match if the path ended with a "/" (unless the full path was "/").
> This patch series changes the behavior to be a match.
>
> I will reply to this email with an additional patch that restores the
> original behavior.
>
> If you move the additional test cases you provide below and the test cases
> in patch 3 to the beginning of the series, you can see the before and after
> behavior of adding patch 1 and patch 2.
Ah, I see. That raises the question about what the behaviour /should/
be. Off the top of my head, matching against a trailing '/' seems to be
okay. Are there situations that you see or can think of where matching
would be the wrong thing to do?
g.
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