Merge tag 'mm-nonmm-stable-2022-10-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-MM updates from Andrew Morton:

 - hfs and hfsplus kmap API modernization (Fabio Francesco)

 - make crash-kexec work properly when invoked from an NMI-time panic
   (Valentin Schneider)

 - ntfs bugfixes (Hawkins Jiawei)

 - improve IPC msg scalability by replacing atomic_t's with percpu
   counters (Jiebin Sun)

 - nilfs2 cleanups (Minghao Chi)

 - lots of other single patches all over the tree!

* tag 'mm-nonmm-stable-2022-10-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (71 commits)
  include/linux/entry-common.h: remove has_signal comment of arch_do_signal_or_restart() prototype
  proc: test how it holds up with mapping'less process
  mailmap: update Frank Rowand email address
  ia64: mca: use strscpy() is more robust and safer
  init/Kconfig: fix unmet direct dependencies
  ia64: update config files
  nilfs2: replace WARN_ONs by nilfs_error for checkpoint acquisition failure
  fork: remove duplicate included header files
  init/main.c: remove unnecessary (void*) conversions
  proc: mark more files as permanent
  nilfs2: remove the unneeded result variable
  nilfs2: delete unnecessary checks before brelse()
  checkpatch: warn for non-standard fixes tag style
  usr/gen_init_cpio.c: remove unnecessary -1 values from int file
  ipc/msg: mitigate the lock contention with percpu counter
  percpu: add percpu_counter_add_local and percpu_counter_sub_local
  fs/ocfs2: fix repeated words in comments
  relay: use kvcalloc to alloc page array in relay_alloc_page_array
  proc: make config PROC_CHILDREN depend on PROC_FS
  fs: uninline inode_maybe_inc_iversion()
  ...

1 files changed, 34 insertions, 14 deletions

diff --git a/ipc/msg.c b/ipc/msg.c
index a0d05775af2c..e4e0990e08f7 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -39,6 +39,7 @@
 #include <linux/nsproxy.h>
 #include <linux/ipc_namespace.h>
 #include <linux/rhashtable.h>
+#include <linux/percpu_counter.h>
 
 #include <asm/current.h>
 #include <linux/uaccess.h>
@@ -285,10 +286,10 @@ static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
 	rcu_read_unlock();
 
 	list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) {
-		atomic_dec(&ns->msg_hdrs);
+		percpu_counter_sub_local(&ns->percpu_msg_hdrs, 1);
 		free_msg(msg);
 	}
-	atomic_sub(msq->q_cbytes, &ns->msg_bytes);
+	percpu_counter_sub_local(&ns->percpu_msg_bytes, msq->q_cbytes);
 	ipc_update_pid(&msq->q_lspid, NULL);
 	ipc_update_pid(&msq->q_lrpid, NULL);
 	ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
@@ -495,17 +496,22 @@ static int msgctl_info(struct ipc_namespace *ns, int msqid,
 	msginfo->msgssz = MSGSSZ;
 	msginfo->msgseg = MSGSEG;
 	down_read(&msg_ids(ns).rwsem);
-	if (cmd == MSG_INFO) {
+	if (cmd == MSG_INFO)
 		msginfo->msgpool = msg_ids(ns).in_use;
-		msginfo->msgmap = atomic_read(&ns->msg_hdrs);
-		msginfo->msgtql = atomic_read(&ns->msg_bytes);
+	max_idx = ipc_get_maxidx(&msg_ids(ns));
+	up_read(&msg_ids(ns).rwsem);
+	if (cmd == MSG_INFO) {
+		msginfo->msgmap = min_t(int,
+				     percpu_counter_sum(&ns->percpu_msg_hdrs),
+				     INT_MAX);
+		msginfo->msgtql = min_t(int,
+		                     percpu_counter_sum(&ns->percpu_msg_bytes),
+				     INT_MAX);
 	} else {
 		msginfo->msgmap = MSGMAP;
 		msginfo->msgpool = MSGPOOL;
 		msginfo->msgtql = MSGTQL;
 	}
-	max_idx = ipc_get_maxidx(&msg_ids(ns));
-	up_read(&msg_ids(ns).rwsem);
 	return (max_idx < 0) ? 0 : max_idx;
 }
 
@@ -935,8 +941,8 @@ static long do_msgsnd(int msqid, long mtype, void __user *mtext,
 		list_add_tail(&msg->m_list, &msq->q_messages);
 		msq->q_cbytes += msgsz;
 		msq->q_qnum++;
-		atomic_add(msgsz, &ns->msg_bytes);
-		atomic_inc(&ns->msg_hdrs);
+		percpu_counter_add_local(&ns->percpu_msg_bytes, msgsz);
+		percpu_counter_add_local(&ns->percpu_msg_hdrs, 1);
 	}
 
 	err = 0;
@@ -1159,8 +1165,8 @@ static long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, in
 			msq->q_rtime = ktime_get_real_seconds();
 			ipc_update_pid(&msq->q_lrpid, task_tgid(current));
 			msq->q_cbytes -= msg->m_ts;
-			atomic_sub(msg->m_ts, &ns->msg_bytes);
-			atomic_dec(&ns->msg_hdrs);
+			percpu_counter_sub_local(&ns->percpu_msg_bytes, msg->m_ts);
+			percpu_counter_sub_local(&ns->percpu_msg_hdrs, 1);
 			ss_wakeup(msq, &wake_q, false);
 
 			goto out_unlock0;
@@ -1297,20 +1303,34 @@ COMPAT_SYSCALL_DEFINE5(msgrcv, int, msqid, compat_uptr_t, msgp,
 }
 #endif
 
-void msg_init_ns(struct ipc_namespace *ns)
+int msg_init_ns(struct ipc_namespace *ns)
 {
+	int ret;
+
 	ns->msg_ctlmax = MSGMAX;
 	ns->msg_ctlmnb = MSGMNB;
 	ns->msg_ctlmni = MSGMNI;
 
-	atomic_set(&ns->msg_bytes, 0);
-	atomic_set(&ns->msg_hdrs, 0);
+	ret = percpu_counter_init(&ns->percpu_msg_bytes, 0, GFP_KERNEL);
+	if (ret)
+		goto fail_msg_bytes;
+	ret = percpu_counter_init(&ns->percpu_msg_hdrs, 0, GFP_KERNEL);
+	if (ret)
+		goto fail_msg_hdrs;
 	ipc_init_ids(&ns->ids[IPC_MSG_IDS]);
+	return 0;
+
+fail_msg_hdrs:
+	percpu_counter_destroy(&ns->percpu_msg_bytes);
+fail_msg_bytes:
+	return ret;
 }
 
 #ifdef CONFIG_IPC_NS
 void msg_exit_ns(struct ipc_namespace *ns)
 {
+	percpu_counter_destroy(&ns->percpu_msg_bytes);
+	percpu_counter_destroy(&ns->percpu_msg_hdrs);
 	free_ipcs(ns, &msg_ids(ns), freeque);
 	idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr);
 	rhashtable_destroy(&ns->ids[IPC_MSG_IDS].key_ht);