Merge branch 'for-5.17/core' into for-linus

- support for USI style pens (Tero Kristo, Mika Westerberg)
- quirk for devices that need inverted X/Y axes (Alistair Francis)
- small core code cleanups and deduplication (Benjamin Tissoires)

1 files changed, 36 insertions, 0 deletions

diff --git a/kernel/pid.c b/kernel/pid.c
index efe87db44683..2fc0a16ec77b 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -540,6 +540,42 @@ struct pid *pidfd_get_pid(unsigned int fd, unsigned int *flags)
 }
 
 /**
+ * pidfd_get_task() - Get the task associated with a pidfd
+ *
+ * @pidfd: pidfd for which to get the task
+ * @flags: flags associated with this pidfd
+ *
+ * Return the task associated with @pidfd. The function takes a reference on
+ * the returned task. The caller is responsible for releasing that reference.
+ *
+ * Currently, the process identified by @pidfd is always a thread-group leader.
+ * This restriction currently exists for all aspects of pidfds including pidfd
+ * creation (CLONE_PIDFD cannot be used with CLONE_THREAD) and pidfd polling
+ * (only supports thread group leaders).
+ *
+ * Return: On success, the task_struct associated with the pidfd.
+ *	   On error, a negative errno number will be returned.
+ */
+struct task_struct *pidfd_get_task(int pidfd, unsigned int *flags)
+{
+	unsigned int f_flags;
+	struct pid *pid;
+	struct task_struct *task;
+
+	pid = pidfd_get_pid(pidfd, &f_flags);
+	if (IS_ERR(pid))
+		return ERR_CAST(pid);
+
+	task = get_pid_task(pid, PIDTYPE_TGID);
+	put_pid(pid);
+	if (!task)
+		return ERR_PTR(-ESRCH);
+
+	*flags = f_flags;
+	return task;
+}
+
+/**
  * pidfd_create() - Create a new pid file descriptor.
  *
  * @pid:   struct pid that the pidfd will reference