lib: Use a bsearch to find the module name

Even with a small number of known drivers (6), a bsearch will take at
most 3 steps, whereas the linear search will take 3 steps on average. In
the future with more known drivers, the logN bsearch will be even more
advantageous.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Katarzyna Dec <katarzyna.dec@intel.com>
Reviewed-by: Katarzyna Dec <katarzyna.dec@intel.com>

1 files changed, 9 insertions, 3 deletions

diff --git a/lib/drmtest.c b/lib/drmtest.c
index 93228f90..bfb38f1e 100644
--- a/lib/drmtest.c
+++ b/lib/drmtest.c
@@ -222,9 +222,15 @@ static int open_device(const char *name, unsigned int chipset)
 	if (__get_drm_device_name(fd, dev_name, sizeof(dev_name) - 1) == -1)
 		goto err;
 
-	for (const struct module *m = modules; m->module; m++) {
-		if (strcmp(m->module, dev_name) == 0) {
-			chip = m->bit;
+	for (int start = 0, end = ARRAY_SIZE(modules) - 1; start < end; ){
+		int mid = start + (end - start) / 2;
+		int ret = strcmp(modules[mid].module, dev_name);
+		if (ret < 0) {
+			end = mid;
+		} else if (ret > 0) {
+			start = mid + 1;
+		} else {
+			chip = modules[mid].bit;
 			break;
 		}
 	}