pidfs: remove pidfs_{get,put}_pid()

Now that we stash persistent information in struct pid there's no need
to play volatile games with pinning struct pid via dentries in pidfs.

Link: https://lore.kernel.org/20250618-work-pidfs-persistent-v2-8-98f3456fd552@kernel.org
Reviewed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>

1 files changed, 1 insertions, 34 deletions

diff --git a/fs/pidfs.c b/fs/pidfs.c
index c49c53d6ae51..bc2342cf4492 100644
--- a/fs/pidfs.c
+++ b/fs/pidfs.c
@@ -895,8 +895,7 @@ static void pidfs_put_data(void *data)
  * pidfs_register_pid - register a struct pid in pidfs
  * @pid: pid to pin
  *
- * Register a struct pid in pidfs. Needs to be paired with
- * pidfs_put_pid() to not risk leaking the pidfs dentry and inode.
+ * Register a struct pid in pidfs.
  *
  * Return: On success zero, on error a negative error code is returned.
  */
@@ -1007,38 +1006,6 @@ struct file *pidfs_alloc_file(struct pid *pid, unsigned int flags)
 	return pidfd_file;
 }
 
-/**
- * pidfs_get_pid - pin a struct pid through pidfs
- * @pid: pid to pin
- *
- * Similar to pidfs_register_pid() but only valid if the caller knows
- * there's a reference to the @pid through a dentry already that can't
- * go away.
- */
-void pidfs_get_pid(struct pid *pid)
-{
-	if (!pid)
-		return;
-	WARN_ON_ONCE(!stashed_dentry_get(&pid->stashed));
-}
-
-/**
- * pidfs_put_pid - drop a pidfs reference
- * @pid: pid to drop
- *
- * Drop a reference to @pid via pidfs. This is only safe if the
- * reference has been taken via pidfs_get_pid().
- */
-void pidfs_put_pid(struct pid *pid)
-{
-	might_sleep();
-
-	if (!pid)
-		return;
-	VFS_WARN_ON_ONCE(!pid->stashed);
-	dput(pid->stashed);
-}
-
 void __init pidfs_init(void)
 {
 	pidfs_attr_cachep = kmem_cache_create("pidfs_attr_cache", sizeof(struct pidfs_attr), 0,