blk-crypto: make blk_crypto_evict_key() return void

blk_crypto_evict_key() is only called in contexts such as inode eviction
where failure is not an option.  So there is nothing the caller can do
with errors except log them.  (dm-table.c does "use" the error code, but
only to pass on to upper layers, so it doesn't really count.)

Just make blk_crypto_evict_key() return void and log errors itself.

Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230315183907.53675-2-ebiggers@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-crypto.c

@@ -13,6 +13,7 @@
 #include <linux/blkdev.h>
 #include <linux/blk-crypto-profile.h>
 #include <linux/module.h>
+#include <linux/ratelimit.h>
 #include <linux/slab.h>
 
 #include "blk-crypto-internal.h"
@@ -408,21 +409,18 @@ int blk_crypto_start_using_key(struct block_device *bdev,
  * Upper layers (filesystems) must call this function to ensure that a key is
  * evicted from any hardware that it might have been programmed into.  The key
  * must not be in use by any in-flight IO when this function is called.
- *
- * Return: 0 on success or if the key wasn't in any keyslot; -errno on error.
  */
-int blk_crypto_evict_key(struct block_device *bdev,
+void blk_crypto_evict_key(struct block_device *bdev,
 			  const struct blk_crypto_key *key)
 {
 	struct request_queue *q = bdev_get_queue(bdev);
+	int err;
 
 	if (blk_crypto_config_supported_natively(bdev, &key->crypto_cfg))
-		return __blk_crypto_evict_key(q->crypto_profile, key);
+		err = __blk_crypto_evict_key(q->crypto_profile, key);
-
+	else
-	/*
+		err = blk_crypto_fallback_evict_key(key);
-	 * If the block_device didn't support the key, then blk-crypto-fallback
+	if (err)
-	 * may have been used, so try to evict the key from blk-crypto-fallback.
+		pr_warn_ratelimited("%pg: error %d evicting key\n", bdev, err);
-	 */
-	return blk_crypto_fallback_evict_key(key);
 }
 EXPORT_SYMBOL_GPL(blk_crypto_evict_key);

drivers/md/dm-table.c

@@ -1202,21 +1202,12 @@ struct dm_crypto_profile {
 	struct mapped_device *md;
 };
 
-struct dm_keyslot_evict_args {
-	const struct blk_crypto_key *key;
-	int err;
-};
-
 static int dm_keyslot_evict_callback(struct dm_target *ti, struct dm_dev *dev,
 				     sector_t start, sector_t len, void *data)
 {
-	struct dm_keyslot_evict_args *args = data;
+	const struct blk_crypto_key *key = data;
-	int err;
 
-	err = blk_crypto_evict_key(dev->bdev, args->key);
+	blk_crypto_evict_key(dev->bdev, key);
-	if (!args->err)
-		args->err = err;
-	/* Always try to evict the key from all devices. */
 	return 0;
 }
 
@@ -1229,7 +1220,6 @@ static int dm_keyslot_evict(struct blk_crypto_profile *profile,
 {
 	struct mapped_device *md =
 		container_of(profile, struct dm_crypto_profile, profile)->md;
-	struct dm_keyslot_evict_args args = { key };
 	struct dm_table *t;
 	int srcu_idx;
 
@@ -1242,11 +1232,12 @@ static int dm_keyslot_evict(struct blk_crypto_profile *profile,
 
 		if (!ti->type->iterate_devices)
 			continue;
-		ti->type->iterate_devices(ti, dm_keyslot_evict_callback, &args);
+		ti->type->iterate_devices(ti, dm_keyslot_evict_callback,
+					  (void *)key);
 	}
 
 	dm_put_live_table(md, srcu_idx);
-	return args.err;
+	return 0;
 }
 
 static int

include/linux/blk-crypto.h

@@ -95,7 +95,7 @@ int blk_crypto_init_key(struct blk_crypto_key *blk_key, const u8 *raw_key,
 int blk_crypto_start_using_key(struct block_device *bdev,
 			       const struct blk_crypto_key *key);
 
-int blk_crypto_evict_key(struct block_device *bdev,
+void blk_crypto_evict_key(struct block_device *bdev,
 			  const struct blk_crypto_key *key);
 
 bool blk_crypto_config_supported_natively(struct block_device *bdev,