ANDROID: block: fix some inline crypto bugs

While we're waiting for v7 of the inline crypto patchset, fix some bugs
that made it into the v6 patchset, including one that caused bios with
an encryption context to never be merged, and one that could cause
non-contiguous pages to incorrectly added to a bio.

Bug: 137270441
Change-Id: I3911fcd6c76b5c9063b86d6af6267ad990a46718
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Satya Tangirala <satyat@google.com>

block/bio-crypt-ctx.c

@@ -96,10 +96,9 @@ bool bio_crypt_ctx_compatible(struct bio *b_1, struct bio *b_2)
 	struct bio_crypt_ctx *bc1 = b_1->bi_crypt_context;
 	struct bio_crypt_ctx *bc2 = b_2->bi_crypt_context;
 
-	if (bc1 != bc2)
-		return false;
-
-	return !bc1 || bc1->bc_key == bc2->bc_key;
+	if (!bc1)
+		return !bc2;
+	return bc2 && bc1->bc_key == bc2->bc_key;
 }
 
 /*

block/blk-crypto-fallback.c

@@ -568,7 +568,7 @@ int blk_crypto_fallback_submit_bio(struct 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_mode])) {
+	if (!tfms_inited[bc->bc_key->crypto_mode]) {
 		bio->bi_status = BLK_STS_IOERR;
 		return -EIO;
 	}

block/blk-crypto-internal.h

@@ -36,7 +36,7 @@ static inline bool bio_crypt_fallback_crypted(const struct bio_crypt_ctx *bc)
 
 static inline int blk_crypto_fallback_submit_bio(struct bio **bio_ptr)
 {
-	pr_warn_once("blk-crypto crypto API fallback disabled; failing request");
+	pr_warn_once("crypto API fallback disabled; failing request\n");
 	(*bio_ptr)->bi_status = BLK_STS_NOTSUPP;
 	return -EIO;
 }

include/linux/bio-crypt-ctx.h

@@ -118,7 +118,7 @@ static inline bool bio_crypt_dun_is_contiguous(const struct bio_crypt_ctx *bc,
 	int i = 0;
 	unsigned int inc = bytes >> bc->bc_key->data_unit_size_bits;
 
-	while (inc && i < BLK_CRYPTO_DUN_ARRAY_SIZE) {
+	while (i < BLK_CRYPTO_DUN_ARRAY_SIZE) {
 		if (bc->bc_dun[i] + inc != next_dun[i])
 			return false;
 		inc = ((bc->bc_dun[i] + inc)  < inc);