module: Use binary search in lookup_symbol()

The function is_exported() with its helper function lookup_symbol() are used to verify if a provided symbol is effectively exported by the kernel or by the modules. Now that both have their symbols sorted we can replace a linear search with a binary search which provide a considerably speed-up. This work was supported by a hardware donation from the CE Linux Forum. Signed-off-by: Alessio Igor Bogani <[email protected]> Acked-by: Greg Kroah-Hartman <[email protected]> Signed-off-by: Rusty Russell <[email protected]>
rtvt123 · May 19, 2011 · 9d63487 · 9d63487
1 parent 403ed27
commit 9d63487
Showing 1 changed file with 2 additions and 5 deletions.
diff --git a/kernel/module.c b/kernel/module.c
@@ -2055,11 +2055,8 @@ static const struct kernel_symbol *lookup_symbol(const char *name,
 	const struct kernel_symbol *start,
 	const struct kernel_symbol *stop)
 {
-	const struct kernel_symbol *ks = start;
-	for (; ks < stop; ks++)
-		if (strcmp(ks->name, name) == 0)
-			return ks;
-	return NULL;
+	return bsearch(name, start, stop - start,
+			sizeof(struct kernel_symbol), cmp_name);
 }
 
 static int is_exported(const char *name, unsigned long value,