rrpc: Round-robin sector target with cost-based gc

This target allows an Open-Channel SSD to be exposed asas a block
device.

It implements a round-robin approach for sector allocation,
together with a greedy cost-based garbage collector.

Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/drivers/lightnvm/Kconfig b/drivers/lightnvm/Kconfig
index 2a27971..a16bf56 100644
--- a/drivers/lightnvm/Kconfig
+++ b/drivers/lightnvm/Kconfig
@@ -32,4 +32,11 @@
 	functionality to device, while keeping data placement and garbage
 	collection decisions on the host.
 
+config NVM_RRPC
+	tristate "Round-robin Hybrid Open-Channel SSD target"
+	---help---
+	Allows an open-channel SSD to be exposed as a block device to the
+	host. The target is implemented using a linear mapping table and
+	cost-based garbage collection. It is optimized for 4K IO sizes.
+
 endif # NVM