[PATCH 6/8] raid6: defer implementation selection when built-in

[Christoph Hellwig]

Don't hold up early boot and defer the selection just like we've been
doing for the RAID5 XOR code since commit 524ccdbdfb52 ("crypto: xor -
defer load time benchmark to a later time").

This will also allow full use of the timing subsystem for benchmarking.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 lib/raid/raid6/algos.c | 37 +++++++++++++++++++++++++++----------
 1 file changed, 27 insertions(+), 10 deletions(-)

diff --git a/lib/raid/raid6/algos.c b/lib/raid/raid6/algos.c
index 6f5c89ab2b17..e7984bde5157 100644
--- a/lib/raid/raid6/algos.c
+++ b/lib/raid/raid6/algos.c
@@ -236,16 +236,6 @@ static int __init raid6_select_algo(void)
 	int i, cycle;
 	int error;
 
-	if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK) || raid6_nr_algos == 1) {
-		pr_info("raid6: skipped pq benchmark and selected %s\n",
-			raid6_algos[raid6_nr_algos - 1]->name);
-		static_call_update(raid6_gen_syndrome_impl,
-				raid6_algos[raid6_nr_algos - 1]->gen_syndrome);
-		static_call_update(raid6_xor_syndrome_impl,
-				raid6_algos[raid6_nr_algos - 1]->xor_syndrome);
-		return 0;
-	}
-
 	/* prepare the buffer and fill it circularly with gfmul table */
 	disk_ptr = kmalloc(PAGE_SIZE * RAID6_TEST_DISKS, GFP_KERNEL);
 	if (!disk_ptr) {
@@ -329,13 +319,40 @@ static int __init raid6_init(void)
 	static_call_update(raid6_recov_datap_impl, raid6_recov_algo->datap);
 	pr_info("raid6: using %s recovery algorithm\n", raid6_recov_algo->name);
 
+	if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK) || raid6_nr_algos == 1) {
+		pr_info("raid6: skipped pq benchmark and selected %s\n",
+			raid6_algos[raid6_nr_algos - 1]->name);
+		goto default_algo;
+	}
+
+#ifdef MODULE
 	return raid6_select_algo();
+#else
+	/*
+	 * Pick the last registered implementation as the temporary default until
+	 * calibration happens.
+	 */
+#endif
+default_algo:
+	static_call_update(raid6_gen_syndrome_impl,
+			raid6_algos[raid6_nr_algos - 1]->gen_syndrome);
+	static_call_update(raid6_xor_syndrome_impl,
+			raid6_algos[raid6_nr_algos - 1]->xor_syndrome);
+	return 0;
 }
 
 static void __exit raid6_exit(void)
 {
 }
 
+/*
+ * When built-in we must register the default implementation before md
+ * initializes, but we don't want calibration to run that early as that
+ * would delay the boot process.
+ */
+#ifndef MODULE
+device_initcall(raid6_select_algo);
+#endif
 subsys_initcall(raid6_init);
 module_exit(raid6_exit);
 MODULE_LICENSE("GPL");
-- 
2.53.0