[PATCH v4 14/15] fs: drop i_verity_info from struct inode

[Christian Brauner <brauner@xxxxxxxxxx>]

Now that all filesystems store the fsverity data pointer in their
private inode, drop the data pointer from struct inode itself freeing up
8 bytes.

Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
---
 fs/verity/open.c         | 18 ++++++------------
 include/linux/fs.h       |  5 -----
 include/linux/fsverity.h | 11 +++++++----
 3 files changed, 13 insertions(+), 21 deletions(-)

diff --git a/fs/verity/open.c b/fs/verity/open.c
index a4d7388e2f71..0dcd33f00361 100644
--- a/fs/verity/open.c
+++ b/fs/verity/open.c
@@ -250,20 +250,15 @@ struct fsverity_info *fsverity_create_info(const struct inode *inode,
 
 void fsverity_set_info(struct inode *inode, struct fsverity_info *vi)
 {
-	void *p;
-
 	/*
 	 * Multiple tasks may race to set ->i_verity_info, so use
 	 * cmpxchg_release().  This pairs with the smp_load_acquire() in
 	 * fsverity_get_info().  I.e., here we publish ->i_verity_info with a
 	 * RELEASE barrier so that other tasks can ACQUIRE it.
 	 */
-
-	if (inode->i_sb->s_vop->inode_info_offs)
-		p = cmpxchg_release(fsverity_addr(inode), NULL, vi);
-	else
-		p = cmpxchg_release(&inode->i_verity_info, NULL, vi);
-	if (p != NULL) {
+	VFS_WARN_ON_ONCE(!inode->i_sb->s_vop);
+	VFS_WARN_ON_ONCE(!inode->i_sb->s_vop->inode_info_offs);
+	if (cmpxchg_release(fsverity_addr(inode), NULL, vi) != NULL) {
 		/* Lost the race, so free the fsverity_info we allocated. */
 		fsverity_free_info(vi);
 		/*
@@ -411,10 +406,9 @@ void __fsverity_cleanup_inode(struct inode *inode)
 {
 	struct fsverity_info **vi;
 
-	if (inode->i_sb->s_vop->inode_info_offs)
-		vi = fsverity_addr(inode);
-	else
-		vi = &inode->i_verity_info;
+	VFS_WARN_ON_ONCE(!inode->i_sb->s_vop);
+	VFS_WARN_ON_ONCE(!inode->i_sb->s_vop->inode_info_offs);
+	vi = fsverity_addr(inode);
 	fsverity_free_info(*vi);
 	*vi = NULL;
 }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index b76a10fc765b..cb249b6646f3 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -73,7 +73,6 @@ struct seq_file;
 struct workqueue_struct;
 struct iov_iter;
 struct fscrypt_operations;
-struct fsverity_info;
 struct fsverity_operations;
 struct fsnotify_mark_connector;
 struct fsnotify_sb_info;
@@ -777,10 +776,6 @@ struct inode {
 	struct fsnotify_mark_connector __rcu	*i_fsnotify_marks;
 #endif
 
-#ifdef CONFIG_FS_VERITY
-	struct fsverity_info	*i_verity_info;
-#endif
-
 	void			*i_private; /* fs or device private pointer */
 } __randomize_layout;
 
diff --git a/include/linux/fsverity.h b/include/linux/fsverity.h
index 75ff6c9c50ef..0ee5b2fea389 100644
--- a/include/linux/fsverity.h
+++ b/include/linux/fsverity.h
@@ -136,7 +136,11 @@ static inline struct fsverity_info **fsverity_addr(const struct inode *inode)
 
 static inline struct fsverity_info *fsverity_get_info(const struct inode *inode)
 {
-	if (!inode->i_sb->s_vop)
+	/*
+	 * We're called from fsverity_active() which might be called on
+	 * inodes from filesystems that don't support fsverity at all.
+	 */
+	if (likely(!inode->i_sb->s_vop))
 		return NULL;
 
 	/*
@@ -145,9 +149,8 @@ static inline struct fsverity_info *fsverity_get_info(const struct inode *inode)
 	 * executing a RELEASE barrier.  We need to use smp_load_acquire() here
 	 * to safely ACQUIRE the memory the other task published.
 	 */
-	if (inode->i_sb->s_vop->inode_info_offs)
-		return smp_load_acquire(fsverity_addr(inode));
-	return smp_load_acquire(&inode->i_verity_info);
+	VFS_WARN_ON_ONCE(!inode->i_sb->s_vop->inode_info_offs);
+	return smp_load_acquire(fsverity_addr(inode));
 }
 
 /* enable.c */

-- 
2.47.2