14  * shared between user space and the kernel and can be resized
24  *   - User space indices may be out of range and must be
27  *   by user space so a local copy is used and a shared copy is
53 	 * kernel space and user space. Kernel reads and writes
55 	 * for read access by user space.
91 		/* protect user space index */  in queue_empty()
97 		/* protect user space index */  in queue_empty()
116 		/* protect user space index */  in queue_full()
122 		/* protect user space index */  in queue_full()
142 		/* protect user space index */  in queue_count()
148 		/* protect user space index */  in queue_count()
166 		pr_warn_once("Normally kernel should not write user space index\n");  in advance_producer()
167 		/* protect user space index */  in advance_producer()
196 		pr_warn_once("Normally kernel should not write user space index\n");  in advance_consumer()
197 		/* protect user space index */  in advance_consumer()
216 		/* protect user space index */  in producer_addr()
240 		/* protect user space index */  in consumer_addr()
259 		/* protect user space index */  in producer_index()
284 		/* protect user space index */  in consumer_index()