fscrypt: use WARN_ON_ONCE instead of WARN_ON

As per Linus's suggestion
(https://lore.kernel.org/r/CAHk-=whefxRGyNGzCzG6BVeM=5vnvgb-XhSeFJVxJyAxAF8XRA@mail.gmail.com),
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/20230320233943.73600-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>

Author: ebiggers

fs/crypto/bio.c

@@ -69,7 +69,7 @@ static int fscrypt_zeroout_range_inline_crypt(const struct inode *inode,
 					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;
 		}
@@ -147,7 +147,7 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 			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. */
@@ -170,7 +170,7 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 			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

@@ -110,7 +110,7 @@ int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname,
 	 * 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);
@@ -570,7 +570,7 @@ u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name)
 {
 	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

@@ -101,7 +101,7 @@ static inline const u8 *fscrypt_context_nonce(const union fscrypt_context *ctx)
 	case FSCRYPT_CONTEXT_V2:
 		return ctx->v2.nonce;
 	}
-	WARN_ON(1);
+	WARN_ON_ONCE(1);
 	return NULL;
 }
 
@@ -386,7 +386,7 @@ fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
 				 const u8 *raw_key,
 				 const struct fscrypt_info *ci)
 {
-	WARN_ON(1);
+	WARN_ON_ONCE(1);
 	return -EOPNOTSUPP;
 }
 

fs/crypto/hkdf.c

@@ -79,7 +79,7 @@ int fscrypt_init_hkdf(struct fscrypt_hkdf *hkdf, const u8 *master_key,
 		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;
 	}
@@ -125,7 +125,7 @@ int fscrypt_hkdf_expand(const struct fscrypt_hkdf *hkdf, u8 context,
 	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

@@ -345,7 +345,7 @@ const char *fscrypt_get_symlink(struct inode *inode, const void *caddr,
 	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

@@ -73,7 +73,7 @@ void fscrypt_put_master_key(struct fscrypt_master_key *mk)
 	 * 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);
@@ -92,7 +92,7 @@ void fscrypt_put_master_key_activeref(struct super_block *sb,
 	 * 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);
@@ -102,8 +102,8 @@ void fscrypt_put_master_key_activeref(struct super_block *sb,
 	 * ->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(
@@ -237,9 +237,9 @@ void fscrypt_destroy_keyring(struct super_block *sb)
 			 * 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

@@ -125,7 +125,7 @@ fscrypt_allocate_skcipher(struct fscrypt_mode *mode, const u8 *raw_key,
 		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;
 	}
@@ -199,7 +199,7 @@ static int setup_per_mode_enc_key(struct fscrypt_info *ci,
 	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];
@@ -282,8 +282,8 @@ int fscrypt_derive_dirhash_key(struct fscrypt_info *ci,
 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);
@@ -503,7 +503,7 @@ static int setup_file_encryption_key(struct fscrypt_info *ci,
 		err = fscrypt_setup_v2_file_key(ci, mk, need_dirhash_key);
 		break;
 	default:
-		WARN_ON(1);
+		WARN_ON_ONCE(1);
 		err = -EINVAL;
 		break;
 	}
@@ -577,7 +577,7 @@ fscrypt_setup_encryption_info(struct inode *inode,
 		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

@@ -48,7 +48,7 @@ int fscrypt_policy_to_key_spec(const union fscrypt_policy *policy,
 		       FSCRYPT_KEY_IDENTIFIER_SIZE);
 		return 0;
 	default:
-		WARN_ON(1);
+		WARN_ON_ONCE(1);
 		return -EINVAL;
 	}
 }
@@ -463,7 +463,7 @@ static int set_encryption_policy(struct inode *inode,
 				     current->comm, current->pid);
 		break;
 	default:
-		WARN_ON(1);
+		WARN_ON_ONCE(1);
 		return -EINVAL;
 	}