crypto: api - Use dedicated workqueue for crypto subsystem

Use dedicated workqueue for crypto subsystem

A dedicated workqueue named kcrypto_wq is created to be used by crypto
subsystem. The system shared keventd_wq is not suitable for
encryption/decryption, because of potential starvation problem.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/Kconfig

@@ -106,6 +106,9 @@ config CRYPTO_NULL
 	help
 	  These are 'Null' algorithms, used by IPsec, which do nothing.
 
+config CRYPTO_WORKQUEUE
+       tristate
+
 config CRYPTO_CRYPTD
 	tristate "Software async crypto daemon"
 	select CRYPTO_BLKCIPHER

crypto/Makefile

@@ -5,6 +5,8 @@
 obj-$(CONFIG_CRYPTO) += crypto.o
 crypto-objs := api.o cipher.o digest.o compress.o
 
+obj-$(CONFIG_CRYPTO_WORKQUEUE) += crypto_wq.o
+
 obj-$(CONFIG_CRYPTO_FIPS) += fips.o
 
 crypto_algapi-$(CONFIG_PROC_FS) += proc.o

crypto/crypto_wq.c

+/*
+ * Workqueue for crypto subsystem
+ *
+ * Copyright (c) 2009 Intel Corp.
+ *   Author: Huang Ying <ying.huang@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ */
+
+#include <linux/workqueue.h>
+#include <crypto/algapi.h>
+#include <crypto/crypto_wq.h>
+
+struct workqueue_struct *kcrypto_wq;
+EXPORT_SYMBOL_GPL(kcrypto_wq);
+
+static int __init crypto_wq_init(void)
+{
+	kcrypto_wq = create_workqueue("crypto");
+	if (unlikely(!kcrypto_wq))
+		return -ENOMEM;
+	return 0;
+}
+
+static void __exit crypto_wq_exit(void)
+{
+	destroy_workqueue(kcrypto_wq);
+}
+
+module_init(crypto_wq_init);
+module_exit(crypto_wq_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Workqueue for crypto subsystem");

include/crypto/crypto_wq.h

+#ifndef CRYPTO_WQ_H
+#define CRYPTO_WQ_H
+
+#include <linux/workqueue.h>
+
+extern struct workqueue_struct *kcrypto_wq;
+#endif