fscrypt: use WARN_ON_ONCE instead of WARN_ON

As per Linus's suggestion
(https://lore.kernel.org/r/CAHk-=whefxRGyNGzCzG6BVeM=[e-mail]),
use WARN_ON_ONCE instead of WARN_ON. This barely adds any extra
overhead, and it makes it so that if any of these ever becomes reachable
(they shouldn't, but that's the point), the logs can't be flooded.

Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Eric Biggers <[e-mail]>

fs/crypto/bio.c

···
 					pblk << (blockbits - SECTOR_SHIFT);
 		}
 		ret = bio_add_page(bio, ZERO_PAGE(0), bytes_this_page, 0);
-		if (WARN_ON(ret != bytes_this_page)) {
+		if (WARN_ON_ONCE(ret != bytes_this_page)) {
 			err = -EIO;
 			goto out;
 		}
···
 			break;
 	}
 	nr_pages = i;
-	if (WARN_ON(nr_pages <= 0))
+	if (WARN_ON_ONCE(nr_pages <= 0))
 		return -EINVAL;
 
 	/* This always succeeds since __GFP_DIRECT_RECLAIM is set. */
···
 			offset += blocksize;
 			if (offset == PAGE_SIZE || len == 0) {
 				ret = bio_add_page(bio, pages[i++], offset, 0);
-				if (WARN_ON(ret != offset)) {
+				if (WARN_ON_ONCE(ret != offset)) {
 					err = -EIO;
 					goto out;
 				}

fs/crypto/fname.c

···
 	 * Copy the filename to the output buffer for encrypting in-place and
 	 * pad it with the needed number of NUL bytes.
 	 */
-	if (WARN_ON(olen < iname->len))
+	if (WARN_ON_ONCE(olen < iname->len))
 		return -ENOBUFS;
 	memcpy(out, iname->name, iname->len);
 	memset(out + iname->len, 0, olen - iname->len);
···
 {
 	const struct fscrypt_info *ci = dir->i_crypt_info;
 
-	WARN_ON(!ci->ci_dirhash_key_initialized);
+	WARN_ON_ONCE(!ci->ci_dirhash_key_initialized);
 
 	return siphash(name->name, name->len, &ci->ci_dirhash_key);
 }

fs/crypto/fscrypt_private.h

···
 	case FSCRYPT_CONTEXT_V2:
 		return ctx->v2.nonce;
 	}
-	WARN_ON(1);
+	WARN_ON_ONCE(1);
 	return NULL;
 }
 
···
 				 const u8 *raw_key,
 				 const struct fscrypt_info *ci)
 {
-	WARN_ON(1);
+	WARN_ON_ONCE(1);
 	return -EOPNOTSUPP;
 }
 

fs/crypto/hkdf.c

···
 		return PTR_ERR(hmac_tfm);
 	}
 
-	if (WARN_ON(crypto_shash_digestsize(hmac_tfm) != sizeof(prk))) {
+	if (WARN_ON_ONCE(crypto_shash_digestsize(hmac_tfm) != sizeof(prk))) {
 		err = -EINVAL;
 		goto err_free_tfm;
 	}
···
 	u8 counter = 1;
 	u8 tmp[HKDF_HASHLEN];
 
-	if (WARN_ON(okmlen > 255 * HKDF_HASHLEN))
+	if (WARN_ON_ONCE(okmlen > 255 * HKDF_HASHLEN))
 		return -EINVAL;
 
 	desc->tfm = hkdf->hmac_tfm;

fs/crypto/hooks.c

···
 	int err;
 
 	/* This is for encrypted symlinks only */
-	if (WARN_ON(!IS_ENCRYPTED(inode)))
+	if (WARN_ON_ONCE(!IS_ENCRYPTED(inode)))
 		return ERR_PTR(-EINVAL);
 
 	/* If the decrypted target is already cached, just return it. */

fs/crypto/keyring.c

···
 	 * fscrypt_master_key struct itself after an RCU grace period ensures
 	 * that concurrent keyring lookups can no longer find it.
 	 */
-	WARN_ON(refcount_read(&mk->mk_active_refs) != 0);
+	WARN_ON_ONCE(refcount_read(&mk->mk_active_refs) != 0);
 	key_put(mk->mk_users);
 	mk->mk_users = NULL;
 	call_rcu(&mk->mk_rcu_head, fscrypt_free_master_key);
···
 	 * destroying any subkeys embedded in it.
 	 */
 
-	if (WARN_ON(!sb->s_master_keys))
+	if (WARN_ON_ONCE(!sb->s_master_keys))
 		return;
 	spin_lock(&sb->s_master_keys->lock);
 	hlist_del_rcu(&mk->mk_node);
···
 	 * ->mk_active_refs == 0 implies that ->mk_secret is not present and
 	 * that ->mk_decrypted_inodes is empty.
 	 */
-	WARN_ON(is_master_key_secret_present(&mk->mk_secret));
-	WARN_ON(!list_empty(&mk->mk_decrypted_inodes));
+	WARN_ON_ONCE(is_master_key_secret_present(&mk->mk_secret));
+	WARN_ON_ONCE(!list_empty(&mk->mk_decrypted_inodes));
 
 	for (i = 0; i <= FSCRYPT_MODE_MAX; i++) {
 		fscrypt_destroy_prepared_key(
···
 			 * with ->mk_secret.  There should be no structural refs
 			 * beyond the one associated with the active ref.
 			 */
-			WARN_ON(refcount_read(&mk->mk_active_refs) != 1);
-			WARN_ON(refcount_read(&mk->mk_struct_refs) != 1);
-			WARN_ON(!is_master_key_secret_present(&mk->mk_secret));
+			WARN_ON_ONCE(refcount_read(&mk->mk_active_refs) != 1);
+			WARN_ON_ONCE(refcount_read(&mk->mk_struct_refs) != 1);
+			WARN_ON_ONCE(!is_master_key_secret_present(&mk->mk_secret));
 			wipe_master_key_secret(&mk->mk_secret);
 			fscrypt_put_master_key_activeref(sb, mk);
 		}

fs/crypto/keysetup.c

···
 		pr_info("fscrypt: %s using implementation \"%s\"\n",
 			mode->friendly_name, crypto_skcipher_driver_name(tfm));
 	}
-	if (WARN_ON(crypto_skcipher_ivsize(tfm) != mode->ivsize)) {
+	if (WARN_ON_ONCE(crypto_skcipher_ivsize(tfm) != mode->ivsize)) {
 		err = -EINVAL;
 		goto err_free_tfm;
 	}
···
 	unsigned int hkdf_infolen = 0;
 	int err;
 
-	if (WARN_ON(mode_num > FSCRYPT_MODE_MAX))
+	if (WARN_ON_ONCE(mode_num > FSCRYPT_MODE_MAX))
 		return -EINVAL;
 
 	prep_key = &keys[mode_num];
···
 void fscrypt_hash_inode_number(struct fscrypt_info *ci,
 			       const struct fscrypt_master_key *mk)
 {
-	WARN_ON(ci->ci_inode->i_ino == 0);
-	WARN_ON(!mk->mk_ino_hash_key_initialized);
+	WARN_ON_ONCE(ci->ci_inode->i_ino == 0);
+	WARN_ON_ONCE(!mk->mk_ino_hash_key_initialized);
 
 	ci->ci_hashed_ino = (u32)siphash_1u64(ci->ci_inode->i_ino,
 					      &mk->mk_ino_hash_key);
···
 		err = fscrypt_setup_v2_file_key(ci, mk, need_dirhash_key);
 		break;
 	default:
-		WARN_ON(1);
+		WARN_ON_ONCE(1);
 		err = -EINVAL;
 		break;
 	}
···
 		res = PTR_ERR(mode);
 		goto out;
 	}
-	WARN_ON(mode->ivsize > FSCRYPT_MAX_IV_SIZE);
+	WARN_ON_ONCE(mode->ivsize > FSCRYPT_MAX_IV_SIZE);
 	crypt_info->ci_mode = mode;
 
 	res = setup_file_encryption_key(crypt_info, need_dirhash_key, &mk);

fs/crypto/policy.c

···
 		       FSCRYPT_KEY_IDENTIFIER_SIZE);
 		return 0;
 	default:
-		WARN_ON(1);
+		WARN_ON_ONCE(1);
 		return -EINVAL;
 	}
 }
···
 				     current->comm, current->pid);
 		break;
 	default:
-		WARN_ON(1);
+		WARN_ON_ONCE(1);
 		return -EINVAL;
 	}