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>
diff --git a/include/crypto/crypto_wq.h b/include/crypto/crypto_wq.h
new file mode 100644
index 0000000..a7d252d
--- /dev/null
+++ b/include/crypto/crypto_wq.h
@@ -0,0 +1,7 @@
+#ifndef CRYPTO_WQ_H
+#define CRYPTO_WQ_H
+
+#include <linux/workqueue.h>
+
+extern struct workqueue_struct *kcrypto_wq;
+#endif