greybus: introduce gb_operation_request_send_sync()
Define a new function used to initiate a synchronous operation.
It sends the operation request message and doesn't return until
the response has been received and/or the operation's result
has been set.
This gets rid of the convention that a null callback pointer
signifies a synchronous operation.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
diff --git a/drivers/staging/greybus/i2c-gb.c b/drivers/staging/greybus/i2c-gb.c
index 19a7df9..bd1bada 100644
--- a/drivers/staging/greybus/i2c-gb.c
+++ b/drivers/staging/greybus/i2c-gb.c
@@ -285,7 +285,7 @@
return -ENOMEM;
/* Synchronous operation--no callback */
- ret = gb_operation_request_send(operation, NULL);
+ ret = gb_operation_request_send_sync(operation);
if (ret) {
if (ret != -EAGAIN)
pr_err("transfer operation failed (%d)\n", ret);
diff --git a/drivers/staging/greybus/operation.c b/drivers/staging/greybus/operation.c
index 15a6e3b..c62f200 100644
--- a/drivers/staging/greybus/operation.c
+++ b/drivers/staging/greybus/operation.c
@@ -641,7 +641,6 @@
struct gb_operation_msg_hdr *header;
unsigned long timeout;
unsigned int cycle;
- int ret;
if (connection->state != GB_CONNECTION_STATE_ENABLED)
return -ENOTCONN;
@@ -652,11 +651,12 @@
*/
gb_operation_get(operation);
- /* A null callback pointer means synchronous return */
- if (callback)
- operation->callback = callback;
- else
- operation->callback = gb_operation_sync_callback;
+ /*
+ * Record the callback function, which is executed in
+ * non-atomic (workqueue) context when the final result
+ * of an operation has been set.
+ */
+ operation->callback = callback;
/*
* Assign the operation's id, and store it in the request header.
@@ -677,8 +677,22 @@
/* All set, send the request */
gb_operation_result_set(operation, -EINPROGRESS);
- ret = gb_message_send(operation->request);
- if (ret || callback)
+
+ return gb_message_send(operation->request);
+}
+
+/*
+ * Send a synchronous operation. This function is expected to
+ * block, returning only when the response has arrived, (or when an
+ * error is detected. The return value is the result of the
+ * operation.
+ */
+int gb_operation_request_send_sync(struct gb_operation *operation)
+{
+ int ret;
+
+ ret = gb_operation_request_send(operation, gb_operation_sync_callback);
+ if (ret)
return ret;
/* Cancel the operation if interrupted */
@@ -923,8 +937,7 @@
if (request_size)
memcpy(operation->request->payload, request, request_size);
- /* Synchronous operation--no callback */
- ret = gb_operation_request_send(operation, NULL);
+ ret = gb_operation_request_send_sync(operation);
if (ret)
pr_err("version operation failed (%d)\n", ret);
else
diff --git a/drivers/staging/greybus/operation.h b/drivers/staging/greybus/operation.h
index c73d9b9..3415e8b 100644
--- a/drivers/staging/greybus/operation.h
+++ b/drivers/staging/greybus/operation.h
@@ -115,6 +115,7 @@
int gb_operation_request_send(struct gb_operation *operation,
gb_operation_callback callback);
+int gb_operation_request_send_sync(struct gb_operation *operation);
int gb_operation_response_send(struct gb_operation *operation, int errno);
void gb_operation_cancel(struct gb_operation *operation, int errno);
diff --git a/drivers/staging/greybus/usb-gb.c b/drivers/staging/greybus/usb-gb.c
index ab4e093..e5da72a 100644
--- a/drivers/staging/greybus/usb-gb.c
+++ b/drivers/staging/greybus/usb-gb.c
@@ -169,7 +169,7 @@
memcpy(&request->payload, urb->transfer_buffer,
urb->transfer_buffer_length);
- ret = gb_operation_request_send(operation, NULL);
+ ret = gb_operation_request_send_sync(operation);
gb_operation_destroy(operation);
return ret;