apparmor: Fix warning: 'decompress_zstd' defined but not used

decompress_zstd() is used in two cases:

- CONFIG SECURITY_APPARMOR_COMPRESSED_POLICY: which allows for
  compressed policy to be loaded
- CONFIG_SECURITY_APPARMOR_EXPORT_BINARY: which allows introspecting
  loaded policy, that is stored in compressed form until it is needed.

When neither of these are selected there is no need for decpress_zstd(),
which results in the decompressed_zstd defined but not used message.
Only define decmpress_zstd() if either of those config options are
enabled. The stub routine is not needed because all calling code is
gated by one of those config options.

Fixes: 1c5f27e845e84 ("apparmor: Fix build failure when ZSTD_DECOMPRESS is not enabled")
Signed-off-by: John Johansen <john.johansen@canonical.com>

1 files changed, 6 insertions, 10 deletions

diff --git a/security/apparmor/apparmorfs.c b/security/apparmor/apparmorfs.c
index 2ae7404526d1..eaee8dc300fa 100644
--- a/security/apparmor/apparmorfs.c
+++ b/security/apparmor/apparmorfs.c
@@ -484,7 +484,8 @@ static struct aa_loaddata *aa_simple_write_to_buffer(const char __user *userbuf,
 	return data;
 }
 
-#ifdef CONFIG_SECURITY_APPARMOR_COMPRESSED_POLICY
+#if defined(CONFIG_SECURITY_APPARMOR_COMPRESSED_POLICY) || \
+    defined(CONFIG_SECURITY_APPARMOR_EXPORT_BINARY)
 static int decompress_zstd(char *src, size_t slen, char *dst, size_t dlen)
 {
 	if (slen < dlen) {
@@ -519,7 +520,10 @@ cleanup:
 	memcpy(dst, src, slen);
 	return 0;
 }
+#endif
+
 
+#ifdef CONFIG_SECURITY_APPARMOR_COMPRESSED_POLICY
 /**
  * aa_get_data_from_compressed - common routine for getting compressed policy
  * from user and get both compressed and uncompressed version.
@@ -531,7 +535,6 @@ cleanup:
  * Returns: kernel buffer containing copy of user buffer data or an
  *          ERR_PTR on failure.
  */
-
 static struct aa_loaddata *aa_get_data_from_compressed(const char __user *userbuf,
 						  size_t buffer_size,
 						  loff_t *pos,
@@ -583,14 +586,6 @@ fail:
 
 }
 #else
-static int decompress_zstd(char *src __always_unused,
-			   size_t slen __always_unused,
-			   char *dst __always_unused,
-			   size_t dlen __always_unused)
-{
-	return -EINVAL;
-}
-
 static struct aa_loaddata *aa_get_data_from_compressed(const char __user *userbuf __always_unused,
 						  size_t buffer_size __always_unused,
 						  loff_t *pos __always_unused,
@@ -599,6 +594,7 @@ static struct aa_loaddata *aa_get_data_from_compressed(const char __user *userbu
 	return ERR_PTR(-EINVAL);
 }
 #endif /* CONFIG_SECURITY_APPARMOR_COMPRESSED_POLICY */
+
 struct aa_user_hdr {
 	uint8_t version;
 	uint8_t compress_level;