[PATCH v3 4/7] block: Modify the blk_crypto_fallback_bio_prep() calling convention

[Bart Van Assche <bvanassche@xxxxxxx>]

Return a bio pointer instead of accepting a struct bio ** argument. No
functionality has been changed.

Suggested-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
 block/blk-crypto-fallback.c | 16 ++++++++--------
 block/blk-crypto-internal.h |  8 ++++----
 block/blk-crypto.c          |  6 ++++--
 3 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/block/blk-crypto-fallback.c b/block/blk-crypto-fallback.c
index 98bba0cf89cc..bd668a52817d 100644
--- a/block/blk-crypto-fallback.c
+++ b/block/blk-crypto-fallback.c
@@ -484,7 +484,7 @@ static void blk_crypto_fallback_decrypt_endio(struct bio *bio)
 /**
  * blk_crypto_fallback_bio_prep - Prepare a bio to use fallback en/decryption
  *
- * @bio_ptr: pointer to the bio to prepare
+ * @bio: bio to prepare
  *
  * If bio is doing a WRITE operation, this splits the bio into two parts if it's
  * too big (see blk_crypto_fallback_split_bio_if_needed()). It then allocates a
@@ -499,28 +499,28 @@ static void blk_crypto_fallback_decrypt_endio(struct bio *bio)
  * of the stack except for blk-integrity (blk-integrity and blk-crypto are not
  * currently supported together).
  *
- * Return: true on success. Sets bio->bi_status and returns false on error.
+ * Return: a bio pointer on success; %NULL upon failure. Sets bio->bi_status on
+ * error.
  */
-bool blk_crypto_fallback_bio_prep(struct bio **bio_ptr)
+struct bio *blk_crypto_fallback_bio_prep(struct bio *bio)
 {
-	struct bio *bio = *bio_ptr;
 	struct bio_crypt_ctx *bc = bio->bi_crypt_context;
 	struct bio_fallback_crypt_ctx *f_ctx;
 
 	if (WARN_ON_ONCE(!tfms_inited[bc->bc_key->crypto_cfg.crypto_mode])) {
 		/* User didn't call blk_crypto_start_using_key() first */
 		bio->bi_status = BLK_STS_IOERR;
-		return false;
+		return NULL;
 	}
 
 	if (!__blk_crypto_cfg_supported(blk_crypto_fallback_profile,
 					&bc->bc_key->crypto_cfg)) {
 		bio->bi_status = BLK_STS_NOTSUPP;
-		return false;
+		return NULL;
 	}
 
 	if (bio_data_dir(bio) == WRITE)
-		return blk_crypto_fallback_encrypt_bio(bio_ptr);
+		return blk_crypto_fallback_encrypt_bio(&bio) ? bio : NULL;
 
 	/*
 	 * bio READ case: Set up a f_ctx in the bio's bi_private and set the
@@ -535,7 +535,7 @@ bool blk_crypto_fallback_bio_prep(struct bio **bio_ptr)
 	bio->bi_end_io = blk_crypto_fallback_decrypt_endio;
 	bio_crypt_free_ctx(bio);
 
-	return true;
+	return bio;
 }
 
 int blk_crypto_fallback_evict_key(const struct blk_crypto_key *key)
diff --git a/block/blk-crypto-internal.h b/block/blk-crypto-internal.h
index e2fd5a3221d3..212e5bbfc95f 100644
--- a/block/blk-crypto-internal.h
+++ b/block/blk-crypto-internal.h
@@ -219,7 +219,7 @@ static inline int blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio,
 
 int blk_crypto_fallback_start_using_mode(enum blk_crypto_mode_num mode_num);
 
-bool blk_crypto_fallback_bio_prep(struct bio **bio_ptr);
+struct bio *blk_crypto_fallback_bio_prep(struct bio *bio);
 
 int blk_crypto_fallback_evict_key(const struct blk_crypto_key *key);
 
@@ -232,11 +232,11 @@ blk_crypto_fallback_start_using_mode(enum blk_crypto_mode_num mode_num)
 	return -ENOPKG;
 }
 
-static inline bool blk_crypto_fallback_bio_prep(struct bio **bio_ptr)
+static inline struct bio *blk_crypto_fallback_bio_prep(struct bio *bio)
 {
 	pr_warn_once("crypto API fallback disabled; failing request.\n");
-	(*bio_ptr)->bi_status = BLK_STS_NOTSUPP;
-	return false;
+	bio->bi_status = BLK_STS_NOTSUPP;
+	return NULL;
 }
 
 static inline int
diff --git a/block/blk-crypto.c b/block/blk-crypto.c
index 84efb65fc51c..4bf8c212aee8 100644
--- a/block/blk-crypto.c
+++ b/block/blk-crypto.c
@@ -281,6 +281,7 @@ void __blk_crypto_free_request(struct request *rq)
  */
 struct bio *__blk_crypto_bio_prep(struct bio *bio)
 {
+	struct bio *new_bio;
 	const struct blk_crypto_key *bc_key = bio->bi_crypt_context->bc_key;
 
 	/* Error if bio has no data. */
@@ -301,8 +302,9 @@ struct bio *__blk_crypto_bio_prep(struct bio *bio)
 	if (blk_crypto_config_supported_natively(bio->bi_bdev,
 						 &bc_key->crypto_cfg))
 		return bio;
-	if (blk_crypto_fallback_bio_prep(&bio))
-		return bio;
+	new_bio = blk_crypto_fallback_bio_prep(bio);
+	if (new_bio)
+		return new_bio;
 fail:
 	bio_endio(bio);
 	return NULL;