[v1,07/10] fscrypt: make ci->ci_direct_key a bool not a pointer

Commit Message

Sweet Tea Dorminy April 10, 2023, 10:16 a.m. UTC

The ci_direct_key field is only used for v1 direct key policies,
recording the direct key that needs to have its refcount reduced when
the crypt_info is freed. However, now that crypt_info->ci_enc_key is a
pointer to the authoritative prepared key -- embedded in the direct key,
in this case, we no longer need to keep a full pointer to the direct key
-- we can use container_of() to go from the prepared key to its
surrounding direct key. Thus we can make ci_direct_key a bool instead of
a pointer, saving a few bytes.

Signed-off-by: Sweet Tea Dorminy <[e-mail]>
---
 fs/crypto/fscrypt_private.h | 7 +++----
 fs/crypto/keysetup.c        | 2 +-
 fs/crypto/keysetup_v1.c     | 7 +++++--
 3 files changed, 9 insertions(+), 7 deletions(-)

Patch

diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 5011737b60b3..b575fb58a506 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -234,10 +234,9 @@  struct fscrypt_info {
 	struct list_head ci_master_key_link;
 
 	/*
-	 * If non-NULL, then encryption is done using the master key directly
-	 * and ci_enc_key will equal ci_direct_key->dk_key.
+	 * If true, then encryption is done using the master key directly.
 	 */
-	struct fscrypt_direct_key *ci_direct_key;
+	bool ci_direct_key;
 
 	/*
 	 * This inode's hash key for filenames.  This is a 128-bit SipHash-2-4
@@ -641,7 +640,7 @@  static inline int fscrypt_require_key(struct inode *inode)
 
 /* keysetup_v1.c */
 
-void fscrypt_put_direct_key(struct fscrypt_direct_key *dk);
+void fscrypt_put_direct_key(struct fscrypt_prepared_key *prep_key);
 
 int fscrypt_setup_v1_file_key(struct fscrypt_info *ci,
 			      const u8 *raw_master_key);
diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c
index 845a92203c87..d81001bf0a51 100644
--- a/fs/crypto/keysetup.c
+++ b/fs/crypto/keysetup.c
@@ -578,7 +578,7 @@  static void put_crypt_info(struct fscrypt_info *ci)
 		return;
 
 	if (ci->ci_direct_key)
-		fscrypt_put_direct_key(ci->ci_direct_key);
+		fscrypt_put_direct_key(ci->ci_enc_key);
 	else if (ci->ci_owns_key) {
 		fscrypt_destroy_prepared_key(ci->ci_inode->i_sb,
 					     ci->ci_enc_key);
diff --git a/fs/crypto/keysetup_v1.c b/fs/crypto/keysetup_v1.c
index e1d761e8067f..09de84c65368 100644
--- a/fs/crypto/keysetup_v1.c
+++ b/fs/crypto/keysetup_v1.c
@@ -160,8 +160,11 @@  static void free_direct_key(struct fscrypt_direct_key *dk)
 	}
 }
 
-void fscrypt_put_direct_key(struct fscrypt_direct_key *dk)
+void fscrypt_put_direct_key(struct fscrypt_prepared_key *prep_key)
 {
+	struct fscrypt_direct_key *dk =
+		container_of(prep_key, struct fscrypt_direct_key, dk_key);
+
 	if (!refcount_dec_and_lock(&dk->dk_refcount, &fscrypt_direct_keys_lock))
 		return;
 	hash_del(&dk->dk_node);
@@ -258,7 +261,7 @@  static int setup_v1_file_key_direct(struct fscrypt_info *ci,
 	dk = fscrypt_get_direct_key(ci, raw_master_key);
 	if (IS_ERR(dk))
 		return PTR_ERR(dk);
-	ci->ci_direct_key = dk;
+	ci->ci_direct_key = true;
 	ci->ci_enc_key = &dk->dk_key;
 	return 0;
 }