linux-kernel - [PATCH 1/7] crypto: octeon - don't disable bottom half in octeon-md5

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Message-Id: <1425845267-14413-2-git-send-email-aaro.koskinen@iki.fi>
Date:	Sun,  8 Mar 2015 22:07:41 +0200
From:	Aaro Koskinen <aaro.koskinen@....fi>
To:	Herbert Xu <herbert@...dor.apana.org.au>,
	"David S. Miller" <davem@...emloft.net>,
	linux-crypto@...r.kernel.org
Cc:	linux-mips@...ux-mips.org, linux-kernel@...r.kernel.org,
	Aaro Koskinen <aaro.koskinen@....fi>
Subject: [PATCH 1/7] crypto: octeon - don't disable bottom half in octeon-md5

Don't disable bottom half while the crypto engine is in use, as it
should be unnecessary: All kernel crypto engine usage is wrapped with
crypto engine state save/restore, so if we get interrupted by softirq
that uses crypto they should save and restore our context.

This actually fixes an issue when running OCTEON MD5 with interrupts
disabled (tcrypt mode=302). There's a WARNING because the module is
trying to enable the bottom half with irqs disabled:

[   52.656610] ------------[ cut here ]------------
[   52.661439] WARNING: CPU: 1 PID: 428 at /home/aaro/git/linux/kernel/softirq.c:150 __local_bh_enable_ip+0x9c/0xd8()
[   52.671780] Modules linked in: tcrypt(+)
[...]
[   52.763539] [<ffffffff8114082c>] warn_slowpath_common+0x94/0xd8
[   52.769465] [<ffffffff81144614>] __local_bh_enable_ip+0x9c/0xd8
[   52.775390] [<ffffffff81119574>] octeon_md5_final+0x12c/0x1e8
[   52.781144] [<ffffffff81337050>] shash_compat_digest+0xd0/0x1b0

Signed-off-by: Aaro Koskinen <aaro.koskinen@....fi>
---
 arch/mips/cavium-octeon/crypto/octeon-md5.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/arch/mips/cavium-octeon/crypto/octeon-md5.c b/arch/mips/cavium-octeon/crypto/octeon-md5.c
index b909881..3dd8845 100644
--- a/arch/mips/cavium-octeon/crypto/octeon-md5.c
+++ b/arch/mips/cavium-octeon/crypto/octeon-md5.c
@@ -97,7 +97,6 @@ static int octeon_md5_update(struct shash_desc *desc, const u8 *data,
 	memcpy((char *)mctx->block + (sizeof(mctx->block) - avail), data,
 	       avail);
 
-	local_bh_disable();
 	preempt_disable();
 	flags = octeon_crypto_enable(&state);
 	octeon_md5_store_hash(mctx);
@@ -115,7 +114,6 @@ static int octeon_md5_update(struct shash_desc *desc, const u8 *data,
 	octeon_md5_read_hash(mctx);
 	octeon_crypto_disable(&state, flags);
 	preempt_enable();
-	local_bh_enable();
 
 	memcpy(mctx->block, data, len);
 
@@ -133,7 +131,6 @@ static int octeon_md5_final(struct shash_desc *desc, u8 *out)
 
 	*p++ = 0x80;
 
-	local_bh_disable();
 	preempt_disable();
 	flags = octeon_crypto_enable(&state);
 	octeon_md5_store_hash(mctx);
@@ -153,7 +150,6 @@ static int octeon_md5_final(struct shash_desc *desc, u8 *out)
 	octeon_md5_read_hash(mctx);
 	octeon_crypto_disable(&state, flags);
 	preempt_enable();
-	local_bh_enable();
 
 	memcpy(out, mctx->hash, sizeof(mctx->hash));
 	memset(mctx, 0, sizeof(*mctx));
-- 
2.2.0

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