Commit d718249b authored by Christian Brauner's avatar Christian Brauner
Browse files

pidfs: remove pidfs_pid_valid() 

The validation is now completely handled in path_from_stashed().

Link: https://lore.kernel.org/20250618-work-pidfs-persistent-v2-9-98f3456fd552@kernel.org


Reviewed-by: default avatarAlexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 804d6794

fs/pidfs.c

+0 −53
Original line number Diff line number Diff line
@@ -804,58 +804,8 @@ static int pidfs_export_permission(struct handle_to_path_ctx *ctx, 
	return 0;

}



static inline bool pidfs_pid_valid(struct pid *pid, const struct path *path,

				   unsigned int flags)

{

	enum pid_type type;



	if (flags & PIDFD_STALE)

		return true;



	/*

	 * Make sure that if a pidfd is created PIDFD_INFO_EXIT

	 * information will be available. So after an inode for the

	 * pidfd has been allocated perform another check that the pid

	 * is still alive. If it is exit information is available even

	 * if the task gets reaped before the pidfd is returned to

	 * userspace. The only exception are indicated by PIDFD_STALE:

	 *

	 * (1) The kernel is in the middle of task creation and thus no

	 *     task linkage has been established yet.

	 * (2) The caller knows @pid has been registered in pidfs at a

	 *     time when the task was still alive.

	 *

	 * In both cases exit information will have been reported.

	 */

	if (flags & PIDFD_THREAD)

		type = PIDTYPE_PID;

	else

		type = PIDTYPE_TGID;



	/*

	 * Since pidfs_exit() is called before struct pid's task linkage

	 * is removed the case where the task got reaped but a dentry

	 * was already attached to struct pid and exit information was

	 * recorded and published can be handled correctly.

	 */

	if (unlikely(!pid_has_task(pid, type))) {

		struct pidfs_attr *attr;



		attr = READ_ONCE(pid->attr);

		if (!attr)

			return false;

		if (!READ_ONCE(attr->exit_info))

			return false;

	}



	return true;

}



static struct file *pidfs_export_open(struct path *path, unsigned int oflags)

{

	if (!pidfs_pid_valid(d_inode(path->dentry)->i_private, path, oflags))

		return ERR_PTR(-ESRCH);



	/*

	 * Clear O_LARGEFILE as open_by_handle_at() forces it and raise

	 * O_RDWR as pidfds always are.
@@ -993,9 +943,6 @@ struct file *pidfs_alloc_file(struct pid *pid, unsigned int flags) 
	if (ret < 0)

		return ERR_PTR(ret);



	if (!pidfs_pid_valid(pid, &path, flags))

		return ERR_PTR(-ESRCH);



	flags &= ~PIDFD_STALE;

	flags |= O_RDWR;

	pidfd_file = dentry_open(&path, flags, current_cred());