linux-kernel - [PATCH 2/7] crypto: octeon - always disable preemption when using crypto engine

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Date:	Sun,  8 Mar 2015 22:07:42 +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 2/7] crypto: octeon - always disable preemption when using crypto engine

Always disable preemption on behalf of the drivers when crypto engine
is taken into use. This will simplify the usage.

Signed-off-by: Aaro Koskinen <aaro.koskinen@....fi>
---
 arch/mips/cavium-octeon/crypto/octeon-crypto.c | 4 +++-
 arch/mips/cavium-octeon/crypto/octeon-md5.c    | 4 ----
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/arch/mips/cavium-octeon/crypto/octeon-crypto.c b/arch/mips/cavium-octeon/crypto/octeon-crypto.c
index 7c82ff4..f66bd1a 100644
--- a/arch/mips/cavium-octeon/crypto/octeon-crypto.c
+++ b/arch/mips/cavium-octeon/crypto/octeon-crypto.c
@@ -17,7 +17,7 @@
  * crypto operations in calls to octeon_crypto_enable/disable in order to make
  * sure the state of COP2 isn't corrupted if userspace is also performing
  * hardware crypto operations. Allocate the state parameter on the stack.
- * Preemption must be disabled to prevent context switches.
+ * Returns with preemption disabled.
  *
  * @state: Pointer to state structure to store current COP2 state in.
  *
@@ -28,6 +28,7 @@ unsigned long octeon_crypto_enable(struct octeon_cop2_state *state)
 	int status;
 	unsigned long flags;
 
+	preempt_disable();
 	local_irq_save(flags);
 	status = read_c0_status();
 	write_c0_status(status | ST0_CU2);
@@ -62,5 +63,6 @@ void octeon_crypto_disable(struct octeon_cop2_state *state,
 	else
 		write_c0_status(read_c0_status() & ~ST0_CU2);
 	local_irq_restore(flags);
+	preempt_enable();
 }
 EXPORT_SYMBOL_GPL(octeon_crypto_disable);
diff --git a/arch/mips/cavium-octeon/crypto/octeon-md5.c b/arch/mips/cavium-octeon/crypto/octeon-md5.c
index 3dd8845..12dccdb 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);
 
-	preempt_disable();
 	flags = octeon_crypto_enable(&state);
 	octeon_md5_store_hash(mctx);
 
@@ -113,7 +112,6 @@ static int octeon_md5_update(struct shash_desc *desc, const u8 *data,
 
 	octeon_md5_read_hash(mctx);
 	octeon_crypto_disable(&state, flags);
-	preempt_enable();
 
 	memcpy(mctx->block, data, len);
 
@@ -131,7 +129,6 @@ static int octeon_md5_final(struct shash_desc *desc, u8 *out)
 
 	*p++ = 0x80;
 
-	preempt_disable();
 	flags = octeon_crypto_enable(&state);
 	octeon_md5_store_hash(mctx);
 
@@ -149,7 +146,6 @@ static int octeon_md5_final(struct shash_desc *desc, u8 *out)
 
 	octeon_md5_read_hash(mctx);
 	octeon_crypto_disable(&state, flags);
-	preempt_enable();
 
 	memcpy(out, mctx->hash, sizeof(mctx->hash));
 	memset(mctx, 0, sizeof(*mctx));
-- 
2.2.0

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