From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frank Rowand Subject: Re: [PATCH 2/3] of: Make of_find_node_by_path() handle /aliases Date: Tue, 20 May 2014 19:41:22 -0700 Message-ID: <537C1252.3090900@gmail.com> References: <1399993115-21552-1-git-send-email-grant.likely@linaro.org> <1399993115-21552-3-git-send-email-grant.likely@linaro.org> <53757D25.1060005@gmail.com> <20140516105444.C1DB7C42277@trevor.secretlab.ca> <20140518092730.109AAC40B8A@trevor.secretlab.ca> Reply-To: frowand.list-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20140518092730.109AAC40B8A-WNowdnHR2B42iJbIjFUEsiwD8/FfD2ys@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Grant Likely Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, David Daney , Pantelis Antoniou List-Id: devicetree@vger.kernel.org On 5/18/2014 2:27 AM, Grant Likely wrote: > On Fri, 16 May 2014 11:54:44 +0100, Grant Likely wrote: >> On Thu, 15 May 2014 19:51:17 -0700, Frank Rowand 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 >>>> Signed-off-by: Pantelis Antoniou >>>> [grant.likely: Rework to not require allocating at runtime] >>>> Acked-by: Rob Herring >>>> Signed-off-by: Grant Likely >>>> --- >>>> 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. > > I've added a couple of test cases to make sure it works correctly: > > diff --git a/drivers/of/selftest.c b/drivers/of/selftest.c > index a9d00e8c17ea..10900b18fc06 100644 > --- a/drivers/of/selftest.c > +++ b/drivers/of/selftest.c > @@ -40,6 +40,12 @@ static void __init of_selftest_find_node_by_name(void) > "find /testcase-data failed\n"); > of_node_put(np); > > + /* Test if trailing '/' works */ > + np = of_find_node_by_path("/testcase-data/"); > + selftest(np && !strcmp("/testcase-data", np->full_name), > + "find /testcase-data/ failed\n"); > + of_node_put(np); > + > np = of_find_node_by_path("/testcase-data/phandle-tests/consumer-a"); > selftest(np && !strcmp("/testcase-data/phandle-tests/consumer-a", np->full_name), > "find /testcase-data/phandle-tests/consumer-a failed\n"); > @@ -50,6 +56,12 @@ static void __init of_selftest_find_node_by_name(void) > "find testcase-alias failed\n"); > of_node_put(np); > > + /* Test if trailing '/' works on aliases */ > + np = of_find_node_by_path("testcase-alias/"); > + selftest(np && !strcmp("/testcase-data", np->full_name), > + "find testcase-alias/ failed\n"); > + of_node_put(np); > + > np = of_find_node_by_path("testcase-alias/phandle-tests/consumer-a"); > selftest(np && !strcmp("/testcase-data/phandle-tests/consumer-a", np->full_name), > "find testcase-alias/phandle-tests/consumer-a failed\n"); > > g. > > >> >>> >>>> + >>>> + for_each_child_of_node(parent, child) { >>>> + const char *name = strrchr(child->full_name, '/'); >>>> + if (WARN(!name, "malformed device_node %s\n", child->full_name)) >>>> + continue; >>>> + name++; < snip > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html