[PATCH v4 25/27] lib/bsearch: Provide __always_inline variant

Peter Zijlstra
2020-02-21T13:34:41Z

For code that needs the ultimate performance (it can inline the @cmp
function too) or simply needs to avoid calling external functions for
whatever reason, provide an __always_inline variant of bsearch().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/kernel/alternative.c | 9 ++++-----
include/linux/bsearch.h | 26 ++++++++++++++++++++++++--
lib/bsearch.c | 22 ++--------------------
3 files changed, 30 insertions(+), 27 deletions(-)

--- a/include/linux/bsearch.h
+++ b/include/linux/bsearch.h
@@ -4,7 +4,29 @@

#include <linux/types.h>

-void *bsearch(const void *key, const void *base, size_t num, size_t size,
- cmp_func_t cmp);
+static __always_inline
+void *__bsearch(const void *key, const void *base, size_t num, size_t size, cmp_func_t cmp)
+{
+ const char *pivot;
+ int result;
+
+ while (num > 0) {
+ pivot = base + (num >> 1) * size;
+ result = cmp(key, pivot);
+
+ if (result == 0)
+ return (void *)pivot;
+
+ if (result > 0) {
+ base = pivot + size;
+ num--;
+ }
+ num >>= 1;
+ }
+
+ return NULL;
+}
+
+extern void *bsearch(const void *key, const void *base, size_t num, size_t size, cmp_func_t cmp);

#endif /* _LINUX_BSEARCH_H */
--- a/lib/bsearch.c
+++ b/lib/bsearch.c
@@ -28,27 +28,9 @@
* the key and elements in the array are of the same type, you can use
* the same comparison function for both sort() and bsearch().
*/
-void *bsearch(const void *key, const void *base, size_t num, size_t size,
- cmp_func_t cmp)
+void *bsearch(const void *key, const void *base, size_t num, size_t size, cmp_func_t cmp)
{
- const char *pivot;
- int result;
-
- while (num > 0) {
- pivot = base + (num >> 1) * size;
- result = cmp(key, pivot);
-
- if (result == 0)
- return (void *)pivot;
-
- if (result > 0) {
- base = pivot + size;
- num--;
- }
- num >>= 1;
- }
-
- return NULL;
+ return __bsearch(key, base, num, size, cmp);
}
EXPORT_SYMBOL(bsearch);
NOKPROBE_SYMBOL(bsearch);