gpu: nvgpu: unit: Sort unit tests by priority

Sort unit tests by their priority before running said unit tests.
There are three available priorities:

  UNIT_PRIO_SELF_TEST
  UNIT_PRIO_POSIX_TEST
  UNIT_PRIO_NVGPU_TEST

Which correspond to the types of testing expected to be run. In
general unit tests should always just use UNIT_PRIO_NVGPU_TEST but
in the case of tests for the POSIX API layer or the unit test
framework the other two priorities are provided.

The reason for this is that it doesn't make much sense to run a
bunch of unit tests if the environment itself or the POSIX API
layer is broken. By placing these tests at the front of the list
of tests to run an engineer will easily be able to see if there
are core problems versus nvgpu problems.

This also lets users fine grain control of test order by adding
or subtracting to UNIT_PRIO_NVGPU_TEST but one must be very
careful about how they do this.

JIRA NVGPU-525

Change-Id: I12a5b798e998f34e4d1168bb3696c579460f20b1
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1741953
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

userspace/src/module.c

@@ -99,6 +99,23 @@ static struct unit_module *load_one_module(struct unit_fw *fw,
 	return mod;
 }
 
+static int cmp_module_prio(const void *__mod_a, const void *__mod_b)
+{
+	const struct unit_module *mod_a = __mod_a;
+	const struct unit_module *mod_b = __mod_b;
+
+	return mod_a->prio > mod_b->prio;
+}
+
+/*
+ * Sort the module list according to prio.
+ */
+static void sort_modules_by_prio(struct unit_module **modules, int nr)
+{
+	qsort(modules, (size_t)nr, sizeof(struct unit_module *),
+	      cmp_module_prio);
+}
+
 /*
  * Load all the modules we can from the module load path. Return the list of
  * loaded module as an array of pointers to modules. The returned list of
@@ -159,6 +176,9 @@ struct unit_module **core_load_modules(struct unit_fw *fw)
 	}
 
 	modules[i] = NULL;
+
+	sort_modules_by_prio(modules, i);
+
 	return modules;
 
 err: