[PATCH v2 21/59] dyndbg-test: change do_prints testpoint to accept a loopct

[Jim Cromie]

echo 1000 > /sys/module/test_dynamic_debug/parameters/do_prints

This allows its use as a scriptable load generator, to generate
dynamic-prefix-emits for flag combinations vs undecorated messages.
This will make it easy to assess the cost of the prefixing.

Reading the ./do_prints node also prints messages (once) to the-log.

NB: the count is clamped to 10000, chosen to be notice able, but not
annoying, and not enough to accidentally flood the logs.

Signed-off-by: Jim Cromie <jim.cro...@gmail.com>
---
 lib/test_dynamic_debug.c | 37 ++++++++++++++++++++++++++-----------
 1 file changed, 26 insertions(+), 11 deletions(-)

diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c
index 9f9e3fddd7e6..4a3d2612ef60 100644
--- a/lib/test_dynamic_debug.c
+++ b/lib/test_dynamic_debug.c
@@ -29,18 +29,30 @@
 
 #include <linux/module.h>
 
-/* re-gen output by reading or writing sysfs node: do_prints */
-
-static void do_prints(void); /* device under test */
+/* re-trigger debug output by reading or writing sysfs node: do_prints */
+#define PRINT_CLAMP 10000
+static void do_prints(unsigned int); /* device under test */
 static int param_set_do_prints(const char *instr, const struct kernel_param 
*kp)
 {
-       do_prints();
+       int rc;
+       unsigned int ct;
+
+       rc = kstrtouint(instr, 0, &ct);
+       if (rc) {
+               pr_err("expecting numeric input, using 1 instead\n");
+               ct = 1;
+       }
+       if (ct > PRINT_CLAMP) {
+               ct = PRINT_CLAMP;
+               pr_info("clamping print-count to %d\n", ct);
+       }
+       do_prints(ct);
        return 0;
 }
 static int param_get_do_prints(char *buffer, const struct kernel_param *kp)
 {
-       do_prints();
-       return scnprintf(buffer, PAGE_SIZE, "did do_prints\n");
+       do_prints(1);
+       return scnprintf(buffer, PAGE_SIZE, "did 1 do_prints\n");
 }
 static const struct kernel_param_ops param_ops_do_prints = {
        .set = param_set_do_prints,
@@ -191,17 +203,20 @@ static void do_levels(void)
        prdbg(V7);
 }
 
-static void do_prints(void)
+static void do_prints(unsigned int ct)
 {
-       pr_debug("do_prints:\n");
-       do_cats();
-       do_levels();
+       /* maybe clamp this */
+       pr_debug("do-prints %d times:\n", ct);
+       for (; ct; ct--) {
+               do_cats();
+               do_levels();
+       }
 }
 
 static int __init test_dynamic_debug_init(void)
 {
        pr_debug("init start\n");
-       do_prints();
+       do_prints(1);
        pr_debug("init done\n");
        return 0;
 }
-- 
2.49.0