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/include/linux/blkdev.h b/include/linux/blkdev.h
index 0c9f879..53fee61 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -497,7 +497,7 @@
 #define QUEUE_FLAG_DISCARD     14	/* supports DISCARD */
 #define QUEUE_FLAG_NOXMERGES   15	/* No extended merges */
 #define QUEUE_FLAG_ADD_RANDOM  16	/* Contributes to random pool */
-#define QUEUE_FLAG_SECDISCARD  17	/* supports SECDISCARD */
+#define QUEUE_FLAG_SECERASE    17	/* supports secure erase */
 #define QUEUE_FLAG_SAME_FORCE  18	/* force complete on same CPU */
 #define QUEUE_FLAG_DEAD        19	/* queue tear-down finished */
 #define QUEUE_FLAG_INIT_DONE   20	/* queue is initialized */
@@ -593,8 +593,8 @@
 #define blk_queue_stackable(q)	\
 	test_bit(QUEUE_FLAG_STACKABLE, &(q)->queue_flags)
 #define blk_queue_discard(q)	test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
-#define blk_queue_secdiscard(q)	(blk_queue_discard(q) && \
-	test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
+#define blk_queue_secure_erase(q) \
+	(test_bit(QUEUE_FLAG_SECERASE, &(q)->queue_flags))
 
 #define blk_noretry_request(rq) \
 	((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
@@ -675,21 +675,6 @@
 	return true;
 }
 
-static inline bool blk_check_merge_flags(unsigned int flags1, unsigned int op1,
-					 unsigned int flags2, unsigned int op2)
-{
-	if ((op1 == REQ_OP_DISCARD) != (op2 == REQ_OP_DISCARD))
-		return false;
-
-	if ((flags1 & REQ_SECURE) != (flags2 & REQ_SECURE))
-		return false;
-
-	if ((op1 == REQ_OP_WRITE_SAME) != (op2 == REQ_OP_WRITE_SAME))
-		return false;
-
-	return true;
-}
-
 static inline bool blk_write_same_mergeable(struct bio *a, struct bio *b)
 {
 	if (bio_data(a) == bio_data(b))
@@ -1158,7 +1143,7 @@
 extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 		sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
 extern int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
-		sector_t nr_sects, gfp_t gfp_mask, int op_flags,
+		sector_t nr_sects, gfp_t gfp_mask, int flags,
 		struct bio **biop);
 extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
 		sector_t nr_sects, gfp_t gfp_mask, struct page *page);