nvmet: add defines for discovery change async events

Add AEN/AER values as defined by the specification
Signed-off-by: NJay Sternberg <jay.e.sternberg@intel.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

drivers/nvme/target/nvmet.h

@@ -36,6 +36,8 @@
  */
 #define NVMET_AEN_CFG_OPTIONAL \
 	(NVME_AEN_CFG_NS_ATTR | NVME_AEN_CFG_ANA_CHANGE)
+#define NVMET_DISC_AEN_CFG_OPTIONAL \
+	(NVME_AEN_CFG_DISC_CHANGE)
 
 /*
  * Plus mandatory SMART AENs (we'll never send them, but allow enabling them):

include/linux/nvme.h

@@ -486,18 +486,21 @@ enum {
 	NVME_AER_NOTICE_NS_CHANGED	= 0x00,
 	NVME_AER_NOTICE_FW_ACT_STARTING = 0x01,
 	NVME_AER_NOTICE_ANA		= 0x03,
+	NVME_AER_NOTICE_DISC_CHANGED	= 0xf0,
 };
 
 enum {
 	NVME_AEN_BIT_NS_ATTR		= 8,
 	NVME_AEN_BIT_FW_ACT		= 9,
 	NVME_AEN_BIT_ANA_CHANGE		= 11,
+	NVME_AEN_BIT_DISC_CHANGE	= 31,
 };
 
 enum {
 	NVME_AEN_CFG_NS_ATTR		= 1 << NVME_AEN_BIT_NS_ATTR,
 	NVME_AEN_CFG_FW_ACT		= 1 << NVME_AEN_BIT_FW_ACT,
 	NVME_AEN_CFG_ANA_CHANGE		= 1 << NVME_AEN_BIT_ANA_CHANGE,
+	NVME_AEN_CFG_DISC_CHANGE	= 1 << NVME_AEN_BIT_DISC_CHANGE,
 };
 
 struct nvme_lba_range_type {