[S390] iucv: Locking free version of iucv_message_(receive|send)

Provide a locking free version of iucv_message_receive and iucv_message_send
that do not call local_bh_enable in a spin_lock_(bh|irqsave)() context.
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>

include/net/iucv/iucv.h

@@ -337,11 +337,34 @@ int iucv_message_purge(struct iucv_path *path, struct iucv_message *msg,
  * established paths. This function will deal with RMDATA messages
  * embedded in struct iucv_message as well.
  *
+ * Locking:	local_bh_enable/local_bh_disable
+ *
  * Returns the result from the CP IUCV call.
  */
 int iucv_message_receive(struct iucv_path *path, struct iucv_message *msg,
 			 u8 flags, void *buffer, size_t size, size_t *residual);
 
+/**
+ * __iucv_message_receive
+ * @path: address of iucv path structure
+ * @msg: address of iucv msg structure
+ * @flags: flags that affect how the message is received (IUCV_IPBUFLST)
+ * @buffer: address of data buffer or address of struct iucv_array
+ * @size: length of data buffer
+ * @residual:
+ *
+ * This function receives messages that are being sent to you over
+ * established paths. This function will deal with RMDATA messages
+ * embedded in struct iucv_message as well.
+ *
+ * Locking:	no locking.
+ *
+ * Returns the result from the CP IUCV call.
+ */
+int __iucv_message_receive(struct iucv_path *path, struct iucv_message *msg,
+			   u8 flags, void *buffer, size_t size,
+			   size_t *residual);
+
 /**
  * iucv_message_reject
  * @path: address of iucv path structure
@@ -386,11 +409,33 @@ int iucv_message_reply(struct iucv_path *path, struct iucv_message *msg,
  * transmitted is in a buffer and this is a one-way message and the
  * receiver will not reply to the message.
  *
+ * Locking:	local_bh_enable/local_bh_disable
+ *
  * Returns the result from the CP IUCV call.
  */
 int iucv_message_send(struct iucv_path *path, struct iucv_message *msg,
 		      u8 flags, u32 srccls, void *buffer, size_t size);
 
+/**
+ * __iucv_message_send
+ * @path: address of iucv path structure
+ * @msg: address of iucv msg structure
+ * @flags: how the message is sent (IUCV_IPRMDATA, IUCV_IPPRTY, IUCV_IPBUFLST)
+ * @srccls: source class of message
+ * @buffer: address of data buffer or address of struct iucv_array
+ * @size: length of send buffer
+ *
+ * This function transmits data to another application. Data to be
+ * transmitted is in a buffer and this is a one-way message and the
+ * receiver will not reply to the message.
+ *
+ * Locking:	no locking.
+ *
+ * Returns the result from the CP IUCV call.
+ */
+int __iucv_message_send(struct iucv_path *path, struct iucv_message *msg,
+			u8 flags, u32 srccls, void *buffer, size_t size);
+
 /**
  * iucv_message_send2way
  * @path: address of iucv path structure

net/iucv/iucv.c

@@ -957,7 +957,7 @@ int iucv_message_purge(struct iucv_path *path, struct iucv_message *msg,
 EXPORT_SYMBOL(iucv_message_purge);
 
 /**
- * iucv_message_receive
+ * iucv_message_receive_iprmdata
  * @path: address of iucv path structure
  * @msg: address of iucv msg structure
  * @flags: how the message is received (IUCV_IPBUFLST)
@@ -965,27 +965,22 @@ EXPORT_SYMBOL(iucv_message_purge);
  * @size: length of data buffer
  * @residual:
  *
- * This function receives messages that are being sent to you over
- * established paths. This function will deal with RMDATA messages
- * embedded in struct iucv_message as well.
- *
- * Returns the result from the CP IUCV call.
+ * Internal function used by iucv_message_receive and __iucv_message_receive
+ * to receive RMDATA data stored in struct iucv_message.
  */
-int iucv_message_receive(struct iucv_path *path, struct iucv_message *msg,
-			 u8 flags, void *buffer, size_t size, size_t *residual)
+static int iucv_message_receive_iprmdata(struct iucv_path *path,
+					 struct iucv_message *msg,
+					 u8 flags, void *buffer,
+					 size_t size, size_t *residual)
 {
-	union iucv_param *parm;
 	struct iucv_array *array;
 	u8 *rmmsg;
 	size_t copy;
-	int rc;
 
-	if (msg->flags & IUCV_IPRMDATA) {
 	/*
 	 * Message is 8 bytes long and has been stored to the
 	 * message descriptor itself.
 	 */
-		rc = (size < 8) ? 5 : 0;
 	if (residual)
 		*residual = abs(size - 8);
 	rmmsg = msg->rmmsg;
@@ -1004,9 +999,34 @@ int iucv_message_receive(struct iucv_path *path, struct iucv_message *msg,
 		memcpy(buffer, rmmsg, min_t(size_t, size, 8));
 	}
 	return 0;
-	}
+}
 
-	local_bh_disable();
+/**
+ * __iucv_message_receive
+ * @path: address of iucv path structure
+ * @msg: address of iucv msg structure
+ * @flags: how the message is received (IUCV_IPBUFLST)
+ * @buffer: address of data buffer or address of struct iucv_array
+ * @size: length of data buffer
+ * @residual:
+ *
+ * This function receives messages that are being sent to you over
+ * established paths. This function will deal with RMDATA messages
+ * embedded in struct iucv_message as well.
+ *
+ * Locking:	no locking
+ *
+ * Returns the result from the CP IUCV call.
+ */
+int __iucv_message_receive(struct iucv_path *path, struct iucv_message *msg,
+			   u8 flags, void *buffer, size_t size, size_t *residual)
+{
+	union iucv_param *parm;
+	int rc;
+
+	if (msg->flags & IUCV_IPRMDATA)
+		return iucv_message_receive_iprmdata(path, msg, flags,
+						     buffer, size, residual);
 	parm = iucv_param[smp_processor_id()];
 	memset(parm, 0, sizeof(union iucv_param));
 	parm->db.ipbfadr1 = (u32)(addr_t) buffer;
@@ -1022,6 +1042,37 @@ int iucv_message_receive(struct iucv_path *path, struct iucv_message *msg,
 		if (residual)
 			*residual = parm->db.ipbfln1f;
 	}
+	return rc;
+}
+EXPORT_SYMBOL(__iucv_message_receive);
+
+/**
+ * iucv_message_receive
+ * @path: address of iucv path structure
+ * @msg: address of iucv msg structure
+ * @flags: how the message is received (IUCV_IPBUFLST)
+ * @buffer: address of data buffer or address of struct iucv_array
+ * @size: length of data buffer
+ * @residual:
+ *
+ * This function receives messages that are being sent to you over
+ * established paths. This function will deal with RMDATA messages
+ * embedded in struct iucv_message as well.
+ *
+ * Locking:	local_bh_enable/local_bh_disable
+ *
+ * Returns the result from the CP IUCV call.
+ */
+int iucv_message_receive(struct iucv_path *path, struct iucv_message *msg,
+			 u8 flags, void *buffer, size_t size, size_t *residual)
+{
+	int rc;
+
+	if (msg->flags & IUCV_IPRMDATA)
+		return iucv_message_receive_iprmdata(path, msg, flags,
+						     buffer, size, residual);
+	local_bh_disable();
+	rc = __iucv_message_receive(path, msg, flags, buffer, size, residual);
 	local_bh_enable();
 	return rc;
 }
@@ -1101,7 +1152,7 @@ int iucv_message_reply(struct iucv_path *path, struct iucv_message *msg,
 EXPORT_SYMBOL(iucv_message_reply);
 
 /**
- * iucv_message_send
+ * __iucv_message_send
  * @path: address of iucv path structure
  * @msg: address of iucv msg structure
  * @flags: how the message is sent (IUCV_IPRMDATA, IUCV_IPPRTY, IUCV_IPBUFLST)
@@ -1113,15 +1164,16 @@ EXPORT_SYMBOL(iucv_message_reply);
  * transmitted is in a buffer and this is a one-way message and the
  * receiver will not reply to the message.
  *
+ * Locking:	no locking
+ *
  * Returns the result from the CP IUCV call.
  */
-int iucv_message_send(struct iucv_path *path, struct iucv_message *msg,
+int __iucv_message_send(struct iucv_path *path, struct iucv_message *msg,
 		      u8 flags, u32 srccls, void *buffer, size_t size)
 {
 	union iucv_param *parm;
 	int rc;
 
-	local_bh_disable();
 	parm = iucv_param[smp_processor_id()];
 	memset(parm, 0, sizeof(union iucv_param));
 	if (flags & IUCV_IPRMDATA) {
@@ -1144,6 +1196,34 @@ int iucv_message_send(struct iucv_path *path, struct iucv_message *msg,
 	rc = iucv_call_b2f0(IUCV_SEND, parm);
 	if (!rc)
 		msg->id = parm->db.ipmsgid;
+	return rc;
+}
+EXPORT_SYMBOL(__iucv_message_send);
+
+/**
+ * iucv_message_send
+ * @path: address of iucv path structure
+ * @msg: address of iucv msg structure
+ * @flags: how the message is sent (IUCV_IPRMDATA, IUCV_IPPRTY, IUCV_IPBUFLST)
+ * @srccls: source class of message
+ * @buffer: address of send buffer or address of struct iucv_array
+ * @size: length of send buffer
+ *
+ * This function transmits data to another application. Data to be
+ * transmitted is in a buffer and this is a one-way message and the
+ * receiver will not reply to the message.
+ *
+ * Locking:	local_bh_enable/local_bh_disable
+ *
+ * Returns the result from the CP IUCV call.
+ */
+int iucv_message_send(struct iucv_path *path, struct iucv_message *msg,
+		      u8 flags, u32 srccls, void *buffer, size_t size)
+{
+	int rc;
+
+	local_bh_disable();
+	rc = __iucv_message_send(path, msg, flags, srccls, buffer, size);
 	local_bh_enable();
 	return rc;
 }