greybus: operation: allow drivers to define custom timeouts

Add new interface gb_operation_request_send_sync_timeout, which allows
drivers to define a custom operation timeout instead of the default
one-second timeout.

The timeout is expected to depend on protocol and operation and
therefore needs to be configurable.

Note that that a timeout of zero is used to wait indefinitely.
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/operation.c

@@ -16,9 +16,6 @@
 
 #include "greybus.h"
 
-/* The default amount of time a request is given to complete */
-#define OPERATION_TIMEOUT_DEFAULT	1000	/* milliseconds */
-
 static struct kmem_cache *gb_operation_cache;
 static struct kmem_cache *gb_message_cache;
 
@@ -690,18 +687,24 @@ EXPORT_SYMBOL_GPL(gb_operation_request_send);
  * error is detected.  The return value is the result of the
  * operation.
  */
-int gb_operation_request_send_sync(struct gb_operation *operation)
+int gb_operation_request_send_sync_timeout(struct gb_operation *operation,
+						unsigned int timeout)
 {
 	int ret;
-	unsigned long timeout;
+	unsigned long timeout_jiffies;
 
 	ret = gb_operation_request_send(operation, gb_operation_sync_callback,
 					GFP_KERNEL);
 	if (ret)
 		return ret;
 
-	timeout = msecs_to_jiffies(OPERATION_TIMEOUT_DEFAULT);
-	ret = wait_for_completion_interruptible_timeout(&operation->completion, timeout);
+	if (timeout)
+		timeout_jiffies = msecs_to_jiffies(timeout);
+	else
+		timeout_jiffies = MAX_SCHEDULE_TIMEOUT;
+
+	ret = wait_for_completion_interruptible_timeout(&operation->completion,
+							timeout_jiffies);
 	if (ret < 0) {
 		/* Cancel the operation if interrupted */
 		gb_operation_cancel(operation, -ECANCELED);
@@ -712,7 +715,7 @@ int gb_operation_request_send_sync(struct gb_operation *operation)
 
 	return gb_operation_result(operation);
 }
-EXPORT_SYMBOL_GPL(gb_operation_request_send_sync);
+EXPORT_SYMBOL_GPL(gb_operation_request_send_sync_timeout);
 
 /*
  * Send a response for an incoming operation request.  A non-zero

drivers/staging/greybus/operation.h

@@ -14,6 +14,9 @@
 
 struct gb_operation;
 
+/* The default amount of time a request is given to complete */
+#define GB_OPERATION_TIMEOUT_DEFAULT	1000	/* milliseconds */
+
 /*
  * No protocol may define an operation that has numeric value 0x00.
  * It is reserved as an explicitly invalid value.
@@ -168,7 +171,14 @@ bool gb_operation_response_alloc(struct gb_operation *operation,
 int gb_operation_request_send(struct gb_operation *operation,
 				gb_operation_callback callback,
 				gfp_t gfp);
-int gb_operation_request_send_sync(struct gb_operation *operation);
+int gb_operation_request_send_sync_timeout(struct gb_operation *operation,
+						unsigned int timeout);
+static inline int
+gb_operation_request_send_sync(struct gb_operation *operation)
+{
+	return gb_operation_request_send_sync_timeout(operation,
+			GB_OPERATION_TIMEOUT_DEFAULT);
+}
 
 void gb_operation_cancel(struct gb_operation *operation, int errno);
 void gb_operation_cancel_incoming(struct gb_operation *operation, int errno);