[PATCH v2 1/8] block: introduce blk_ksm_is_empty()

[Satya Tangirala]

This function checks if a given keyslot manager supports any encryption
mode/data unit size combination (and returns true if there is no such
supported combination). Helps clean up code a little.

Signed-off-by: Satya Tangirala <satyat@xxxxxxxxxx>
---
 block/keyslot-manager.c         | 13 +++++++++++++
 drivers/md/dm-table.c           | 11 +----------
 include/linux/keyslot-manager.h |  2 ++
 3 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/block/keyslot-manager.c b/block/keyslot-manager.c
index 2c4a55bea6ca..2a2b1a9785d2 100644
--- a/block/keyslot-manager.c
+++ b/block/keyslot-manager.c
@@ -437,6 +437,19 @@ void blk_ksm_destroy(struct blk_keyslot_manager *ksm)
 }
 EXPORT_SYMBOL_GPL(blk_ksm_destroy);
 
+bool blk_ksm_is_empty(struct blk_keyslot_manager *ksm)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ksm->crypto_modes_supported); i++) {
+		if (ksm->crypto_modes_supported[i])
+			return false;
+	}
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(blk_ksm_is_empty);
+
 bool blk_ksm_register(struct blk_keyslot_manager *ksm, struct request_queue *q)
 {
 	if (blk_integrity_queue_supports_integrity(q)) {
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 95391f78b8d5..db18a58adad7 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1313,7 +1313,6 @@ static int dm_table_construct_keyslot_manager(struct dm_table *t)
 	struct blk_keyslot_manager *ksm;
 	struct dm_target *ti;
 	unsigned int i;
-	bool ksm_is_empty = true;
 
 	dksm = kmalloc(sizeof(*dksm), GFP_KERNEL);
 	if (!dksm)
@@ -1350,15 +1349,7 @@ static int dm_table_construct_keyslot_manager(struct dm_table *t)
 	 * If the new KSM doesn't actually support any crypto modes, we may as
 	 * well represent it with a NULL ksm.
 	 */
-	ksm_is_empty = true;
-	for (i = 0; i < ARRAY_SIZE(ksm->crypto_modes_supported); i++) {
-		if (ksm->crypto_modes_supported[i]) {
-			ksm_is_empty = false;
-			break;
-		}
-	}
-
-	if (ksm_is_empty) {
+	if (blk_ksm_is_empty(ksm)) {
 		dm_destroy_keyslot_manager(ksm);
 		ksm = NULL;
 	}
diff --git a/include/linux/keyslot-manager.h b/include/linux/keyslot-manager.h
index a27605e2f826..5bf0cea20c81 100644
--- a/include/linux/keyslot-manager.h
+++ b/include/linux/keyslot-manager.h
@@ -117,4 +117,6 @@ bool blk_ksm_is_superset(struct blk_keyslot_manager *ksm_superset,
 void blk_ksm_update_capabilities(struct blk_keyslot_manager *target_ksm,
 				 struct blk_keyslot_manager *reference_ksm);
 
+bool blk_ksm_is_empty(struct blk_keyslot_manager *ksm);
+
 #endif /* __LINUX_KEYSLOT_MANAGER_H */
-- 
2.31.0.291.g576ba9dcdaf-goog