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Date: Mon, 16 May 2016 19:52:33 +0300
From: Pantelis Antoniou <pantelis.antoniou@...sulko.com>
To: Rob Herring <robherring2@...il.com>
Cc: Frank Rowand <frowand.list@...il.com>,
Matt Porter <mporter@...sulko.com>,
Grant Likely <grant.likely@...retlab.ca>,
Koen Kooi <koen@...inion.thruhere.net>,
Guenter Roeck <linux@...ck-us.net>,
Marek Vasut <marex@...x.de>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
Pantelis Antoniou <pantelis.antoniou@...sulko.com>,
Pantelis Antoniou <panto@...oniou-consulting.com>
Subject: [PATCH v2 2/5] of: Support hashtable lookups for phandles
When a device tree contains a lot of phandles, resolving one
takes time because the original method uses a search against
all nodes (not just the ones with phandles).
Signed-off-by: Pantelis Antoniou <pantelis.antoniou@...sulko.com>
---
drivers/of/base.c | 41 ++++++++++++++++++++++++++++++++++++++---
drivers/of/dynamic.c | 8 ++++++++
drivers/of/of_private.h | 33 +++++++++++++++++++++++++++++++++
include/linux/of.h | 2 ++
4 files changed, 81 insertions(+), 3 deletions(-)
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 20bbc2f..436a088 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -27,6 +27,7 @@
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/proc_fs.h>
+#include <linux/rhashtable.h>
#include "of_private.h"
@@ -41,6 +42,18 @@ static const char *of_stdout_options;
struct kset *of_kset;
+const struct rhashtable_params of_phandle_ht_params = {
+ .key_offset = offsetof(struct device_node, phandle), /* base offset */
+ .key_len = sizeof(phandle),
+ .head_offset = offsetof(struct device_node, ht_node),
+ .automatic_shrinking = true,
+};
+
+struct rhashtable *of_phandle_ht;
+
+/* default is false */
+bool of_phandle_ht_is_disabled;
+
/*
* Used to protect the of_aliases, to hold off addition of nodes to sysfs.
* This mutex must be held whenever modifications are being made to the
@@ -162,6 +175,12 @@ int __of_attach_node_post(struct device_node *np)
struct property *pp;
int rc;
+ if (of_phandle_ht_available()) {
+ rc = of_phandle_ht_insert(np);
+ WARN(rc, "insert to phandle hash fail @%s\n",
+ of_node_full_name(np));
+ }
+
if (!IS_ENABLED(CONFIG_SYSFS))
return 0;
@@ -194,6 +213,17 @@ void __init of_core_init(void)
struct device_node *np;
int ret;
+ of_phandle_ht = kzalloc(sizeof(*of_phandle_ht), GFP_KERNEL);
+ if (!of_phandle_ht) {
+ pr_warn("devicetree: Failed to allocate hashtable\n");
+ return;
+ }
+ ret = rhashtable_init(of_phandle_ht, &of_phandle_ht_params);
+ if (ret) {
+ pr_warn("devicetree: Failed to initialize hashtable\n");
+ return;
+ }
+
/* Create the kset, and register existing nodes */
mutex_lock(&of_mutex);
of_kset = kset_create_and_add("devicetree", NULL, firmware_kobj);
@@ -1073,9 +1103,14 @@ struct device_node *of_find_node_by_phandle(phandle handle)
return NULL;
raw_spin_lock_irqsave(&devtree_lock, flags);
- for_each_of_allnodes(np)
- if (np->phandle == handle)
- break;
+ /* when we're ready use the hash table (and not disabled) */
+ if (of_phandle_ht_available() && !of_phandle_ht_is_disabled)
+ np = of_phandle_ht_lookup(handle);
+ else { /* fallback */
+ for_each_of_allnodes(np)
+ if (np->phandle == handle)
+ break;
+ }
of_node_get(np);
raw_spin_unlock_irqrestore(&devtree_lock, flags);
return np;
diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index 34ca783..931b905 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -11,6 +11,7 @@
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/proc_fs.h>
+#include <linux/rhashtable.h>
#include "of_private.h"
@@ -44,6 +45,13 @@ EXPORT_SYMBOL(of_node_put);
void __of_detach_node_post(struct device_node *np)
{
struct property *pp;
+ int rc;
+
+ if (of_phandle_ht_available()) {
+ rc = of_phandle_ht_remove(np);
+ WARN(rc, "remove from phandle hash fail @%s\n",
+ of_node_full_name(np));
+ }
if (!IS_ENABLED(CONFIG_SYSFS))
return;
diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
index 10b0342..386ae71 100644
--- a/drivers/of/of_private.h
+++ b/drivers/of/of_private.h
@@ -101,4 +101,37 @@ static inline int of_overlay_init(void)
}
#endif
+extern const struct rhashtable_params of_phandle_ht_params;
+extern struct rhashtable *of_phandle_ht;
+
+/* for unittest use */
+extern bool of_phandle_ht_is_disabled;
+
+static inline bool of_phandle_ht_available(void)
+{
+ return of_phandle_ht != NULL;
+}
+
+static inline int of_phandle_ht_insert(struct device_node *np)
+{
+ if (!np || !np->phandle)
+ return 0;
+ return rhashtable_insert_fast(of_phandle_ht,
+ &np->ht_node, of_phandle_ht_params);
+}
+
+static inline int of_phandle_ht_remove(struct device_node *np)
+{
+ if (!np || !np->phandle)
+ return 0;
+ return rhashtable_remove_fast(of_phandle_ht,
+ &np->ht_node, of_phandle_ht_params);
+}
+
+static inline struct device_node *of_phandle_ht_lookup(phandle handle)
+{
+ return rhashtable_lookup_fast(of_phandle_ht,
+ &handle, of_phandle_ht_params);
+}
+
#endif /* _LINUX_OF_PRIVATE_H */
diff --git a/include/linux/of.h b/include/linux/of.h
index 18a8e59..9de9a3f 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -25,6 +25,7 @@
#include <linux/notifier.h>
#include <linux/property.h>
#include <linux/list.h>
+#include <linux/rhashtable.h>
#include <asm/byteorder.h>
#include <asm/errno.h>
@@ -52,6 +53,7 @@ struct device_node {
phandle phandle;
const char *full_name;
struct fwnode_handle fwnode;
+ struct rhash_head ht_node;
struct property *properties;
struct property *deadprops; /* removed properties */
--
1.7.12
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