From 82e269ad8afe1c73aa6c28dca3c23fecc6c8b616 Mon Sep 17 00:00:00 2001
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Tue, 28 Sep 2021 13:54:01 +0200
Subject: [PATCH] crypto: testmgr - Only disable migration in crypto_disable_simd_for_test()
Git-commit: 82e269ad8afe1c73aa6c28dca3c23fecc6c8b616
Patch-mainline: v5.16-rc1
References: bsc#1189998

crypto_disable_simd_for_test() disables preemption in order to receive a
stable per-CPU variable which it needs to modify in order to alter
crypto_simd_usable() results.

This can also be achived by migrate_disable() which forbidds CPU
migrations but allows the task to be preempted. The latter is important
for PREEMPT_RT since operation like skcipher_walk_first() may allocate
memory which must not happen with disabled preemption on PREEMPT_RT.

Use migrate_disable() in crypto_disable_simd_for_test() to achieve a
stable per-CPU pointer.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>

---
 crypto/testmgr.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/crypto/testmgr.c b/crypto/testmgr.c
index 70f69f0910c9..58eee8eab4bf 100644
--- a/crypto/testmgr.c
+++ b/crypto/testmgr.c
@@ -1061,14 +1061,14 @@ static void generate_random_testvec_config(struct testvec_config *cfg,
 
 static void crypto_disable_simd_for_test(void)
 {
-	preempt_disable();
+	migrate_disable();
 	__this_cpu_write(crypto_simd_disabled_for_test, true);
 }
 
 static void crypto_reenable_simd_for_test(void)
 {
 	__this_cpu_write(crypto_simd_disabled_for_test, false);
-	preempt_enable();
+	migrate_enable();
 }
 
 /*
-- 
2.26.2