From 9999e48639b3cecb08ffb37358bcba3b48161b29 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Fri, 10 May 2024 08:50:17 +0000
Subject: [PATCH] add ax88772_rst

---
 kernel/fs/proc/base.c |   52 +++++++++++++++++++++++++++++++++++++++++-----------
 1 files changed, 41 insertions(+), 11 deletions(-)

diff --git a/kernel/fs/proc/base.c b/kernel/fs/proc/base.c
index efab1a9..8b1ecb5 100644
--- a/kernel/fs/proc/base.c
+++ b/kernel/fs/proc/base.c
@@ -96,7 +96,6 @@
 #include <linux/posix-timers.h>
 #include <linux/time_namespace.h>
 #include <linux/resctrl.h>
-#include <linux/swait.h>
 #include <linux/cpufreq_times.h>
 #include <trace/events/oom.h>
 #include "internal.h"
@@ -1883,7 +1882,7 @@
 	put_pid(pid);
 }
 
-struct inode *proc_pid_make_inode(struct super_block * sb,
+struct inode *proc_pid_make_inode(struct super_block *sb,
 				  struct task_struct *task, umode_t mode)
 {
 	struct inode * inode;
@@ -1912,11 +1911,6 @@
 
 	/* Let the pid remember us for quick removal */
 	ei->pid = pid;
-	if (S_ISDIR(mode)) {
-		spin_lock(&pid->lock);
-		hlist_add_head_rcu(&ei->sibling_inodes, &pid->inodes);
-		spin_unlock(&pid->lock);
-	}
 
 	task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
 	security_task_to_inode(task, inode);
@@ -1927,6 +1921,39 @@
 out_unlock:
 	iput(inode);
 	return NULL;
+}
+
+/*
+ * Generating an inode and adding it into @pid->inodes, so that task will
+ * invalidate inode's dentry before being released.
+ *
+ * This helper is used for creating dir-type entries under '/proc' and
+ * '/proc/<tgid>/task'. Other entries(eg. fd, stat) under '/proc/<tgid>'
+ * can be released by invalidating '/proc/<tgid>' dentry.
+ * In theory, dentries under '/proc/<tgid>/task' can also be released by
+ * invalidating '/proc/<tgid>' dentry, we reserve it to handle single
+ * thread exiting situation: Any one of threads should invalidate its
+ * '/proc/<tgid>/task/<pid>' dentry before released.
+ */
+static struct inode *proc_pid_make_base_inode(struct super_block *sb,
+				struct task_struct *task, umode_t mode)
+{
+	struct inode *inode;
+	struct proc_inode *ei;
+	struct pid *pid;
+
+	inode = proc_pid_make_inode(sb, task, mode);
+	if (!inode)
+		return NULL;
+
+	/* Let proc_flush_pid find this directory inode */
+	ei = PROC_I(inode);
+	pid = ei->pid;
+	spin_lock(&pid->lock);
+	hlist_add_head_rcu(&ei->sibling_inodes, &pid->inodes);
+	spin_unlock(&pid->lock);
+
+	return inode;
 }
 
 int pid_getattr(const struct path *path, struct kstat *stat,
@@ -2040,7 +2067,7 @@
 
 	child = d_hash_and_lookup(dir, &qname);
 	if (!child) {
-		DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
+		DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
 		child = d_alloc_parallel(dir, &qname, &wq);
 		if (IS_ERR(child))
 			goto end_instantiate;
@@ -3346,7 +3373,8 @@
 {
 	struct inode *inode;
 
-	inode = proc_pid_make_inode(dentry->d_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
+	inode = proc_pid_make_base_inode(dentry->d_sb, task,
+					 S_IFDIR | S_IRUGO | S_IXUGO);
 	if (!inode)
 		return ERR_PTR(-ENOENT);
 
@@ -3511,7 +3539,8 @@
 }
 
 static const struct inode_operations proc_tid_comm_inode_operations = {
-		.permission = proc_tid_comm_permission,
+		.setattr	= proc_setattr,
+		.permission	= proc_tid_comm_permission,
 };
 
 /*
@@ -3644,7 +3673,8 @@
 	struct task_struct *task, const void *ptr)
 {
 	struct inode *inode;
-	inode = proc_pid_make_inode(dentry->d_sb, task, S_IFDIR | S_IRUGO | S_IXUGO);
+	inode = proc_pid_make_base_inode(dentry->d_sb, task,
+					 S_IFDIR | S_IRUGO | S_IXUGO);
 	if (!inode)
 		return ERR_PTR(-ENOENT);
 

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