lib: Add generic binary search function to the kernel.

There a large number hand-coded binary searches in the kernel (run
"git grep search | grep binary" to find many of them).  Since in my
experience, hand-coding binary searches can be error-prone, it seems
worth cleaning this up by providing a generic binary search function.

This generic binary search implementation comes from Ksplice.  It has
the same basic API as the C library bsearch() function.  Ksplice uses
it in half a dozen places with 4 different comparison functions, and I
think our code is substantially cleaner because of this.

Signed-off-by: Tim Abbott <tabbott@ksplice.com>
Extra-bikeshedding-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Extra-bikeshedding-by: André Goddard Rosa <andre.goddard@gmail.com>
Extra-bikeshedding-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Alessio Igor Bogani <abogani@kernel.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 9 insertions, 0 deletions

diff --git a/include/linux/bsearch.h b/include/linux/bsearch.h
new file mode 100644
index 000000000000..90b1aa867224
--- /dev/null
+++ b/include/linux/bsearch.h
@@ -0,0 +1,9 @@
+#ifndef _LINUX_BSEARCH_H
+#define _LINUX_BSEARCH_H
+
+#include <linux/types.h>
+
+void *bsearch(const void *key, const void *base, size_t num, size_t size,
+              int (*cmp)(const void *key, const void *elt));
+
+#endif /* _LINUX_BSEARCH_H */