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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: linux-crypto@vger.kernel.org
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
	"David S. Miller" <davem@davemloft.net>,
	Thomas Gleixner <tglx@linutronix.de>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: [PATCH] crypto: testmgr - Only disable migration in crypto_disable_simd_for_test()
Date: Tue, 28 Sep 2021 13:54:01 +0200	[thread overview]
Message-ID: <20210928115401.441339-1-bigeasy@linutronix.de> (raw)

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

--- a/crypto/testmgr.c
+++ b/crypto/testmgr.c
@@ -1061,14 +1061,14 @@ static void generate_random_testvec_conf
 
 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();
 }
 
 /*

             reply	other threads:[~2021-09-28 11:54 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-28 11:54 Sebastian Andrzej Siewior [this message]
2021-10-05 18:17 ` Eric Biggers
2021-10-07  9:42   ` Sebastian Andrzej Siewior
2021-10-07 17:53     ` Eric Biggers
2021-10-07 19:03       ` Sebastian Andrzej Siewior
2021-10-08 11:34         ` Herbert Xu
2021-10-08 12:24 ` Herbert Xu

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