linux-kernel - [PATCH 2/2] module: use bsearch in find_symbol_in_kernel

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Message-Id: <1253726926-5504-3-git-send-email-tabbott@ksplice.com>
Date:	Wed, 23 Sep 2009 13:28:46 -0400
From:	Tim Abbott <tabbott@...lice.com>
To:	Alan Jenkins <alan-jenkins@...fmail.co.uk>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	rusty@...tcorp.com.au, linux-kbuild@...r.kernel.org,
	linux-modules@...r.kernel.org, Tim Abbott <tabbott@...lice.com>
Subject: [PATCH 2/2] module: use bsearch in find_symbol_in_kernel_section.

Signed-off-by: Tim Abbott <tabbott@...lice.com>
---
 kernel/module.c |   34 +++++++++++++++-------------------
 1 files changed, 15 insertions(+), 19 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 9b19f23..25ff16b 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -55,6 +55,7 @@
 #include <linux/async.h>
 #include <linux/percpu.h>
 #include <linux/kmemleak.h>
+#include <linux/bsearch.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/module.h>
@@ -209,31 +210,26 @@ struct symsearch {
 #define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
 #endif
 
-/* binary search on sorted symbols */
+static int symbol_compare(const void *key, const void *elt)
+{
+	const char *str = key;
+	const struct kernel_symbol *sym = elt;
+	return strcmp(sym->name, str);
+}
+
 static bool find_symbol_in_kernel_section(const struct symsearch *syms,
 					  const char *name,
 					  unsigned int *symnum)
 {
-	int lo = 0, hi = syms->stop - syms->start - 1;
-	int mid, cmp;
-
-	while (lo <= hi) {
-		mid = (lo + hi) / 2;
-		cmp = strcmp(syms->start[mid].name, name);
-		if (cmp == 0) {
-			*symnum = mid;
-			return true;
-		}
-		else if (cmp < 0)
-			hi = mid - 1;
-		else
-			lo = mid + 1;
-	}
-
-	return false;
+	const struct kernel_symbol *sym =
+	    bsearch(name, syms->start, syms->stop - syms->start,
+		    sizeof(*syms->start), symbol_compare);
+	if (sym == NULL)
+		return false;
+	*symnum = sym - syms->start;
+	return true;
 }
 
-
 static bool find_symbol_in_kernel(const char *name,
 				  struct symsearch *sym,
 				  unsigned int *symnum)
-- 
1.6.3.3

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