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Message-ID: <50AC17A4.2040507@gmail.com>
Date: Tue, 20 Nov 2012 17:52:04 -0600
From: Rob Herring <robherring2@...il.com>
To: Stephen Warren <swarren@...dotorg.org>
CC: John Stultz <johnstul@...ibm.com>,
Thomas Gleixner <tglx@...utronix.de>,
Grant Likely <grant.likely@...retlab.ca>,
Rob Herring <rob.herring@...xeda.com>,
Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
Josh Cartwright <josh.cartwright@...il.com>,
Stephen Warren <swarren@...dia.com>,
Arnd Bergmann <arnd@...db.de>, linux-kernel@...r.kernel.org,
linux-tegra@...r.kernel.org, Olof Johansson <olof@...om.net>,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH V4 1/3] of: introduce for_each_matching_node_and_match()
On 11/20/2012 05:12 PM, Stephen Warren wrote:
> From: Stephen Warren <swarren@...dia.com>
>
> The following pattern of code is tempting:
>
> for_each_matching_node(np, table) {
> match = of_match_node(table, np);
>
> However, this results in iterating over table twice; the second time
> inside of_match_node(). The implementation of for_each_matching_node()
> already found the match, so this is redundant. Invent new function
> of_find_matching_node_and_match() and macro
> for_each_matching_node_and_match() to remove the double iteration,
> thus transforming the above code to:
>
> for_each_matching_node_and_match(np, table, &match)
>
> Signed-off-by: Stephen Warren <swarren@...dia.com>
> ---
> v4: New patch.
>
> This series is based on the ARM sys_timer rework that I posted yesterday,
> although patch 1/3 should be completely independant of that, and could
> perhaps even be applied for 3.8 right now.
Agreed. I will apply for 3.8 assuming no further comments in the next
few days.
Rob
> I hope that these patches can be taken through arm-soc tree for 3.9;
> I will repost them based on 3.8-rc1 at the appropriate time.
> ---
> drivers/of/base.c | 18 +++++++++++++-----
> include/linux/of.h | 15 +++++++++++++--
> 2 files changed, 26 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index f2f63c8..094271e 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -594,27 +594,35 @@ const struct of_device_id *of_match_node(const struct of_device_id *matches,
> EXPORT_SYMBOL(of_match_node);
>
> /**
> - * of_find_matching_node - Find a node based on an of_device_id match
> - * table.
> + * of_find_matching_node_and_match - Find a node based on an of_device_id
> + * match table.
> * @from: The node to start searching from or NULL, the node
> * you pass will not be searched, only the next one
> * will; typically, you pass what the previous call
> * returned. of_node_put() will be called on it
> * @matches: array of of device match structures to search in
> + * @match Updated to point at the matches entry which matched
> *
> * Returns a node pointer with refcount incremented, use
> * of_node_put() on it when done.
> */
> -struct device_node *of_find_matching_node(struct device_node *from,
> - const struct of_device_id *matches)
> +struct device_node *of_find_matching_node_and_match(struct device_node *from,
> + const struct of_device_id *matches,
> + const struct of_device_id **match)
> {
> struct device_node *np;
>
> + if (match)
> + *match = NULL;
> +
> read_lock(&devtree_lock);
> np = from ? from->allnext : allnodes;
> for (; np; np = np->allnext) {
> - if (of_match_node(matches, np) && of_node_get(np))
> + if (of_match_node(matches, np) && of_node_get(np)) {
> + if (match)
> + *match = matches;
> break;
> + }
> }
> of_node_put(from);
> read_unlock(&devtree_lock);
> diff --git a/include/linux/of.h b/include/linux/of.h
> index 681a6c8..1000496 100644
> --- a/include/linux/of.h
> +++ b/include/linux/of.h
> @@ -180,11 +180,22 @@ extern struct device_node *of_find_compatible_node(struct device_node *from,
> #define for_each_compatible_node(dn, type, compatible) \
> for (dn = of_find_compatible_node(NULL, type, compatible); dn; \
> dn = of_find_compatible_node(dn, type, compatible))
> -extern struct device_node *of_find_matching_node(struct device_node *from,
> - const struct of_device_id *matches);
> +extern struct device_node *of_find_matching_node_and_match(
> + struct device_node *from,
> + const struct of_device_id *matches,
> + const struct of_device_id **match);
> +static inline struct device_node *of_find_matching_node(
> + struct device_node *from,
> + const struct of_device_id *matches)
> +{
> + return of_find_matching_node_and_match(from, matches, NULL);
> +}
> #define for_each_matching_node(dn, matches) \
> for (dn = of_find_matching_node(NULL, matches); dn; \
> dn = of_find_matching_node(dn, matches))
> +#define for_each_matching_node_and_match(dn, matches, match) \
> + for (dn = of_find_matching_node_and_match(NULL, matches, match); \
> + dn; dn = of_find_matching_node_and_match(dn, matches, match))
> extern struct device_node *of_find_node_by_path(const char *path);
> extern struct device_node *of_find_node_by_phandle(phandle handle);
> extern struct device_node *of_get_parent(const struct device_node *node);
>
--
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