greybus: add a reference to pending operations
Grab an extra reference to an operation before sending it. Drop
that reference at the end of its completion handling.
It turns out gb_operation_get() got deleted along the way, so this
re-introduces it. We're assuming we only get a reference when
there's at least one in existence so we don't need a semaphore to
protect it. Emphasize this by *not* returning a pointer to
the referenced operation.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
diff --git a/drivers/staging/greybus/operation.c b/drivers/staging/greybus/operation.c
index 9ad714e..ab27cd9 100644
--- a/drivers/staging/greybus/operation.c
+++ b/drivers/staging/greybus/operation.c
@@ -157,6 +157,7 @@
operation->callback(operation);
else
complete_all(&operation->completion);
+ gb_operation_put(operation);
}
/*
@@ -410,6 +411,14 @@
}
/*
+ * Get an additional reference on an operation.
+ */
+void gb_operation_get(struct gb_operation *operation)
+{
+ kref_get(&operation->kref);
+}
+
+/*
* Destroy a previously created operation.
*/
static void _gb_operation_destroy(struct kref *kref)
@@ -429,6 +438,10 @@
kmem_cache_free(gb_operation_cache, operation);
}
+/*
+ * Drop a reference on an operation, and destroy it when the last
+ * one is gone.
+ */
void gb_operation_put(struct gb_operation *operation)
{
if (!WARN_ON(!operation))
@@ -454,11 +467,11 @@
return -ENOTCONN;
/*
- * XXX
- * I think the order of operations is going to be
- * significant, and if so, we may need a mutex to surround
- * setting the operation id and submitting the buffer.
+ * First, get an extra reference on the operation.
+ * It'll be dropped when the operation completes.
*/
+ gb_operation_get(operation);
+
operation->callback = callback;
gb_pending_operation_insert(operation);
diff --git a/drivers/staging/greybus/operation.h b/drivers/staging/greybus/operation.h
index f608844..befce15 100644
--- a/drivers/staging/greybus/operation.h
+++ b/drivers/staging/greybus/operation.h
@@ -88,7 +88,7 @@
struct gb_operation *gb_operation_create(struct gb_connection *connection,
u8 type, size_t request_size,
size_t response_size);
-struct gb_operation *gb_operation_get(struct gb_operation *operation);
+void gb_operation_get(struct gb_operation *operation);
void gb_operation_put(struct gb_operation *operation);
static inline void gb_operation_destroy(struct gb_operation *operation)
{