[PATCH] module: Use binary search in lookup_symbol()

From: Alessio Igor Bogani
Date: Wed May 18 2011 - 16:36:18 EST

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 <abogani@xxxxxxxxxx>
Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
kernel/module.c | 7 ++-----
1 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 1e2b657..795bdc7 100644
--- 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,

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