From 82e26f73b2a8ee4acc2507494430aa5774da2b74 Mon Sep 17 00:00:00 2001
From: Alex Elder <elder@linaro.org>
Date: Tue, 2 Dec 2014 08:30:39 -0600
Subject: [PATCH] greybus: send operation response messages
Define a helper function gb_operation_response_alloc() and use it
to allocate the response buffer for outgoing operations in
gb_operation_create_common(.
Use it also in gb_operation_response_send() if the caller has not
allocated a response buffer.
Once a response buffer is allocated, fill in its result code and
send it.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
---
drivers/staging/greybus/operation.c | 60 +++++++++++++++++++++++------
drivers/staging/greybus/operation.h | 3 ++
2 files changed, 52 insertions(+), 11 deletions(-)
diff --git a/drivers/staging/greybus/operation.c b/drivers/staging/greybus/operation.c
index f3246818d7770..1409d31f48c0f 100644
--- a/drivers/staging/greybus/operation.c
+++ b/drivers/staging/greybus/operation.c
@@ -471,6 +471,34 @@ static u8 gb_operation_errno_map(int errno)
}
}
+bool gb_operation_response_alloc(struct gb_operation *operation,
+ size_t response_size)
+{
+ struct greybus_host_device *hd = operation->connection->hd;
+ struct gb_operation_msg_hdr *request_header;
+ struct gb_message *response;
+ u8 type;
+
+ request_header = operation->request->header;
+ type = request_header->type | GB_OPERATION_TYPE_RESPONSE;
+ response = gb_operation_message_alloc(hd, type, response_size,
+ GFP_KERNEL);
+ if (!response)
+ return false;
+ response->operation = operation;
+
+ /*
+ * Size and type get initialized when the message is
+ * allocated. The errno will be set before sending. All
+ * that's left is the operation id, which we copy from the
+ * request message header (as-is, in little-endian order).
+ */
+ response->header->operation_id = request_header->operation_id;
+ operation->response = response;
+
+ return true;
+}
+
/*
* Create a Greybus operation to be sent over the given connection.
* The request buffer will be big enough for a payload of the given
@@ -513,14 +541,9 @@ gb_operation_create_common(struct gb_connection *connection, u8 type,
operation->request->operation = operation;
/* Allocate the response buffer for outgoing operations */
- if (type) {
- type |= GB_OPERATION_TYPE_RESPONSE;
- operation->response = gb_operation_message_alloc(hd, type,
- response_size, GFP_KERNEL);
- if (!operation->response)
+ if (type)
+ if (!gb_operation_response_alloc(operation, response_size))
goto err_request;
- operation->response->operation = operation;
- }
operation->errno = -EBADR; /* Initial value--means "never set" */
INIT_WORK(&operation->work, gb_operation_work);
@@ -680,7 +703,13 @@ int gb_operation_request_send(struct gb_operation *operation,
}
/*
- * Send a response for an incoming operation request.
+ * Send a response for an incoming operation request. A non-zero
+ * errno indicates a failed operation.
+ *
+ * If there is any response payload, the incoming request handler is
+ * responsible for allocating the response message. Otherwise the
+ * it can simply supply the result errno; this function will
+ * allocate the response message if necessary.
*/
int gb_operation_response_send(struct gb_operation *operation, int errno)
{
@@ -689,10 +718,19 @@ int gb_operation_response_send(struct gb_operation *operation, int errno)
pr_err("request result already set\n");
return -EIO; /* Shouldn't happen */
}
- (void)gb_operation_errno_map; /* avoid a build warning */
- gb_operation_destroy(operation);
- return 0;
+ if (!operation->response) {
+ if (!gb_operation_response_alloc(operation, 0)) {
+ pr_err("error allocating response\n");
+ /* XXX Respond with pre-allocated -ENOMEM? */
+ return -ENOMEM;
+ }
+ }
+
+ /* Fill in the response header and send it */
+ operation->response->header->result = gb_operation_errno_map(errno);
+
+ return gb_message_send(operation->response);
}
/*
diff --git a/drivers/staging/greybus/operation.h b/drivers/staging/greybus/operation.h
index adaec7c43ea94..c60decb405399 100644
--- a/drivers/staging/greybus/operation.h
+++ b/drivers/staging/greybus/operation.h
@@ -98,6 +98,9 @@ static inline void gb_operation_destroy(struct gb_operation *operation)
gb_operation_put(operation);
}
+bool gb_operation_response_alloc(struct gb_operation *operation,
+ size_t response_size);
+
int gb_operation_request_send(struct gb_operation *operation,
gb_operation_callback callback);
int gb_operation_response_send(struct gb_operation *operation, int errno);
--
2.30.2