[PATCH v4 04/13] powerpc/rtas: Factor out function descriptor lookup

[Nathan Lynch via B4 Relay <devnull+nathanl.linux.ibm.com@kernel.org>]

From: Nathan Lynch <nathanl@linux.ibm.com>

Move the function descriptor table lookup out of rtas_function_token()
into a separate routine for use in new code to follow. No functional
change.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
 arch/powerpc/kernel/rtas.c | 31 +++++++++++++++++++------------
 1 file changed, 19 insertions(+), 12 deletions(-)

diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index f0051881348a..1fc0b3fffdd1 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -469,29 +469,36 @@ static struct rtas_function rtas_function_table[] __ro_after_init = {
 static DEFINE_RAW_SPINLOCK(rtas_lock);
 static struct rtas_args rtas_args;
 
-/**
- * rtas_function_token() - RTAS function token lookup.
- * @handle: Function handle, e.g. RTAS_FN_EVENT_SCAN.
- *
- * Context: Any context.
- * Return: the token value for the function if implemented by this platform,
- *         otherwise RTAS_UNKNOWN_SERVICE.
- */
-s32 rtas_function_token(const rtas_fn_handle_t handle)
+static struct rtas_function *rtas_function_lookup(const rtas_fn_handle_t handle)
 {
 	const size_t index = handle.index;
 	const bool out_of_bounds = index >= ARRAY_SIZE(rtas_function_table);
 
 	if (WARN_ONCE(out_of_bounds, "invalid function index %zu", index))
-		return RTAS_UNKNOWN_SERVICE;
+		return NULL;
 	/*
 	 * Various drivers attempt token lookups on non-RTAS
 	 * platforms.
 	 */
 	if (!rtas.dev)
-		return RTAS_UNKNOWN_SERVICE;
+		return NULL;
+
+	return &rtas_function_table[index];
+}
+
+/**
+ * rtas_function_token() - RTAS function token lookup.
+ * @handle: Function handle, e.g. RTAS_FN_EVENT_SCAN.
+ *
+ * Context: Any context.
+ * Return: the token value for the function if implemented by this platform,
+ *         otherwise RTAS_UNKNOWN_SERVICE.
+ */
+s32 rtas_function_token(const rtas_fn_handle_t handle)
+{
+	const struct rtas_function *func = rtas_function_lookup(handle);
 
-	return rtas_function_table[index].token;
+	return func ? func->token : RTAS_UNKNOWN_SERVICE;
 }
 EXPORT_SYMBOL_GPL(rtas_function_token);
 

-- 
2.41.0