Merge tag 'kernel-7.0-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull pidfs updates from Christian Brauner:

 - pid: introduce task_ppid_vnr() helper

 - pidfs: convert rb-tree to rhashtable

   Mateusz reported performance penalties during task creation because
   pidfs uses pidmap_lock to add elements into the rbtree. Switch to an
   rhashtable to have separate fine-grained locking and to decouple from
   pidmap_lock moving all heavy manipulations outside of it

   Also move inode allocation outside of pidmap_lock. With this there's
   nothing happening for pidfs under pidmap_lock

 - pid: reorder fields in pid_namespace to reduce false sharing

 - Revert "pid: make __task_pid_nr_ns(ns => NULL) safe for zombie
   callers"

 - ipc: Add SPDX license id to mqueue.c

* tag 'kernel-7.0-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  pid: introduce task_ppid_vnr() helper
  pidfs: implement ino allocation without the pidmap lock
  Revert "pid: make __task_pid_nr_ns(ns => NULL) safe for zombie callers"
  pid: reorder fields in pid_namespace to reduce false sharing
  pidfs: convert rb-tree to rhashtable
  ipc: Add SPDX license id to mqueue.c

3 files changed, 16 insertions, 10 deletions

diff --git a/include/linux/pid.h b/include/linux/pid.h
index 003a1027d219..ddaef0bbc8ba 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -6,6 +6,7 @@
 #include <linux/rculist.h>
 #include <linux/rcupdate.h>
 #include <linux/refcount.h>
+#include <linux/rhashtable-types.h>
 #include <linux/sched.h>
 #include <linux/wait.h>
 
@@ -60,7 +61,7 @@ struct pid {
 	spinlock_t lock;
 	struct {
 		u64 ino;
-		struct rb_node pidfs_node;
+		struct rhash_head pidfs_hash;
 		struct dentry *stashed;
 		struct pidfs_attr *attr;
 	};
@@ -73,7 +74,6 @@ struct pid {
 	struct upid numbers[];
 };
 
-extern seqcount_spinlock_t pidmap_lock_seq;
 extern struct pid init_struct_pid;
 
 struct file;
@@ -310,6 +310,11 @@ static inline pid_t task_ppid_nr_ns(const struct task_struct *tsk, struct pid_na
 	return pid;
 }
 
+static inline pid_t task_ppid_vnr(const struct task_struct *tsk)
+{
+	return task_ppid_nr_ns(tsk, NULL);
+}
+
 static inline pid_t task_ppid_nr(const struct task_struct *tsk)
 {
 	return task_ppid_nr_ns(tsk, &init_pid_ns);
diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index 0e7ae12c96d2..b20baaa7e62b 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -27,6 +27,13 @@ struct pid_namespace {
 	struct idr idr;
 	struct rcu_head rcu;
 	unsigned int pid_allocated;
+#ifdef CONFIG_SYSCTL
+#if defined(CONFIG_MEMFD_CREATE)
+	int memfd_noexec_scope;
+#endif
+	struct ctl_table_set	set;
+	struct ctl_table_header *sysctls;
+#endif
 	struct task_struct *child_reaper;
 	struct kmem_cache *pid_cachep;
 	unsigned int level;
@@ -40,13 +47,6 @@ struct pid_namespace {
 	int reboot;	/* group exit code if this pidns was rebooted */
 	struct ns_common ns;
 	struct work_struct	work;
-#ifdef CONFIG_SYSCTL
-	struct ctl_table_set	set;
-	struct ctl_table_header *sysctls;
-#if defined(CONFIG_MEMFD_CREATE)
-	int memfd_noexec_scope;
-#endif
-#endif
 } __randomize_layout;
 
 extern struct pid_namespace init_pid_ns;
diff --git a/include/linux/pidfs.h b/include/linux/pidfs.h
index 3e08c33da2df..416bdff4d6ce 100644
--- a/include/linux/pidfs.h
+++ b/include/linux/pidfs.h
@@ -6,7 +6,8 @@ struct coredump_params;
 
 struct file *pidfs_alloc_file(struct pid *pid, unsigned int flags);
 void __init pidfs_init(void);
-void pidfs_add_pid(struct pid *pid);
+void pidfs_prepare_pid(struct pid *pid);
+int pidfs_add_pid(struct pid *pid);
 void pidfs_remove_pid(struct pid *pid);
 void pidfs_exit(struct task_struct *tsk);
 #ifdef CONFIG_COREDUMP