KVM: arm64: Don't open code ARRAY_SIZE()

Use ARRAY_SIZE() instead of an open-coded version.
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Kalesh Singh <kaleshsingh@google.com>
Tested-by: Kalesh Singh <kaleshsingh@google.com>
Link: https://lore.kernel.org/r/20220727142906.1856759-6-maz@kernel.org

arch/arm64/kvm/hyp/nvhe/stacktrace.c

@@ -103,14 +103,13 @@ static void notrace unwind(struct unwind_state *state,
 static bool pkvm_save_backtrace_entry(void *arg, unsigned long where)
 {
 	unsigned long *stacktrace = this_cpu_ptr(pkvm_stacktrace);
-	int size = NVHE_STACKTRACE_SIZE / sizeof(long);
 	int *idx = (int *)arg;
 
 	/*
 	 * Need 2 free slots: 1 for current entry and 1 for the
 	 * delimiter.
 	 */
-	if (*idx > size - 2)
+	if (*idx > ARRAY_SIZE(pkvm_stacktrace) - 2)
 		return false;
 
 	stacktrace[*idx] = where;

arch/arm64/kvm/stacktrace.c

@@ -187,11 +187,13 @@ static void pkvm_dump_backtrace(unsigned long hyp_offset)
 {
 	unsigned long *stacktrace
 		= (unsigned long *) this_cpu_ptr_nvhe_sym(pkvm_stacktrace);
-	int i, size = NVHE_STACKTRACE_SIZE / sizeof(long);
+	int i;
 
 	kvm_nvhe_dump_backtrace_start();
 	/* The saved stacktrace is terminated by a null entry */
-	for (i = 0; i < size && stacktrace[i]; i++)
+	for (i = 0;
+	     i < ARRAY_SIZE(kvm_nvhe_sym(pkvm_stacktrace)) && stacktrace[i];
+	     i++)
 		kvm_nvhe_dump_backtrace_entry((void *)hyp_offset, stacktrace[i]);
 	kvm_nvhe_dump_backtrace_end();
 }