block: add a separate operation type for secure erase

Instead of overloading the discard support with the REQ_SECURE flag.
Use the opportunity to rename the queue flag as well, and remove the
dead checks for this flag in the RAID 1 and RAID 10 drivers that don't
claim support for secure erase.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 03b0dd9..af49caf 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -1791,6 +1791,10 @@
 	case REQ_OP_DISCARD:
 		rwbs[i++] = 'D';
 		break;
+	case REQ_OP_SECURE_ERASE:
+		rwbs[i++] = 'D';
+		rwbs[i++] = 'E';
+		break;
 	case REQ_OP_FLUSH:
 		rwbs[i++] = 'F';
 		break;
@@ -1809,8 +1813,6 @@
 		rwbs[i++] = 'S';
 	if (rw & REQ_META)
 		rwbs[i++] = 'M';
-	if (rw & REQ_SECURE)
-		rwbs[i++] = 'E';
 
 	rwbs[i] = '\0';
 }