[PATCH 10/17] raid6: use static_call for gen_syndrom and xor_syndrom

[Christoph Hellwig]

Avoid indirect calls for P/Q parity generation.

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 lib/raid/raid6/algos.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/lib/raid/raid6/algos.c b/lib/raid/raid6/algos.c
index f9e8a8752e2d..b81c7594f6c4 100644
--- a/lib/raid/raid6/algos.c
+++ b/lib/raid/raid6/algos.c
@@ -14,6 +14,7 @@
 #include <linux/module.h>
 #include <linux/gfp.h>
 #include <linux/raid/pq.h>
+#include <linux/static_call.h>
 #include <kunit/visibility.h>
 #include "algos.h"
 
@@ -23,7 +24,8 @@ static unsigned int raid6_nr_algos;
 static const struct raid6_recov_calls *raid6_recov_algo;
 
 /* Selected algorithm */
-static struct raid6_calls raid6_call;
+DEFINE_STATIC_CALL_NULL(raid6_gen_syndrome_impl, *raid6_intx1.gen_syndrome);
+DEFINE_STATIC_CALL_NULL(raid6_xor_syndrome_impl, *raid6_intx1.xor_syndrome);
 
 /**
  * raid6_gen_syndrome - generate RAID6 P/Q parity
@@ -47,7 +49,7 @@ void raid6_gen_syndrome(int disks, size_t bytes, void **ptrs)
 	lockdep_assert_preemption_enabled();
 	WARN_ON_ONCE(bytes & 511);
 
-	raid6_call.gen_syndrome(disks, bytes, ptrs);
+	static_call(raid6_gen_syndrome_impl)(disks, bytes, ptrs);
 }
 EXPORT_SYMBOL_GPL(raid6_gen_syndrome);
 
@@ -83,7 +85,7 @@ void raid6_xor_syndrome(int disks, int start, int stop, size_t bytes,
 	WARN_ON_ONCE(bytes & 511);
 	WARN_ON_ONCE(stop < start);
 
-	raid6_call.xor_syndrome(disks, start, stop, bytes, ptrs);
+	static_call(raid6_xor_syndrome_impl)(disks, start, stop, bytes, ptrs);
 }
 EXPORT_SYMBOL_GPL(raid6_xor_syndrome);
 
@@ -94,7 +96,7 @@ EXPORT_SYMBOL_GPL(raid6_xor_syndrome);
  */
 bool raid6_can_xor_syndrome(void)
 {
-	return !!raid6_call.xor_syndrome;
+	return !!static_call_query(raid6_xor_syndrome_impl);
 }
 EXPORT_SYMBOL_GPL(raid6_can_xor_syndrome);
 
@@ -193,7 +195,8 @@ static int raid6_choose_gen(void *(*const dptrs)[RAID6_TEST_DISKS],
 		return -EINVAL;
 	}
 
-	raid6_call = *best;
+	static_call_update(raid6_gen_syndrome_impl, best->gen_syndrome);
+	static_call_update(raid6_xor_syndrome_impl, best->xor_syndrome);
 
 	pr_info("raid6: using algorithm %s gen() %ld MB/s\n",
 		best->name,
@@ -238,7 +241,10 @@ static int __init raid6_select_algo(void)
 	if (!IS_ENABLED(CONFIG_RAID6_PQ_BENCHMARK) || raid6_nr_algos == 1) {
 		pr_info("raid6: skipped pq benchmark and selected %s\n",
 			raid6_algos[0]->name);
-		raid6_call = *raid6_algos[0];
+		static_call_update(raid6_gen_syndrome_impl,
+				raid6_algos[0]->gen_syndrome);
+		static_call_update(raid6_xor_syndrome_impl,
+				raid6_algos[0]->xor_syndrome);
 		return 0;
 	}
 
-- 
2.47.3