add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/drivers/connector/cn_proc.c
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@@ -1,3 +1,4 @@
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+// SPDX-License-Identifier: GPL-2.0-or-later
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 /*
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  * cn_proc.c - process events connector
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  *
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  * Based on cn_fork.c by Guillaume Thouvenin <guillaume.thouvenin@bull.net>
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  * Original copyright notice follows:
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  * Copyright (C) 2005 BULL SA.
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- *
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- *
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- * This program is free software; you can redistribute it and/or modify
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- * it under the terms of the GNU General Public License as published by
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- * the Free Software Foundation; either version 2 of the License, or
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- * (at your option) any later version.
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- *
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- * This program is distributed in the hope that it will be useful,
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- * but WITHOUT ANY WARRANTY; without even the implied warranty of
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- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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- * GNU General Public License for more details.
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- *
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- * You should have received a copy of the GNU General Public License
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- * along with this program; if not, write to the Free Software
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- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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  */
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 #include <linux/kernel.h>
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@@ -32,6 +18,7 @@
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 #include <linux/pid_namespace.h>
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 #include <linux/cn_proc.h>
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+#include <linux/local_lock.h>
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 /*
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  * Size of a cn_msg followed by a proc_event structure.  Since the
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@@ -52,25 +39,31 @@
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 static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);
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 static struct cb_id cn_proc_event_id = { CN_IDX_PROC, CN_VAL_PROC };
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-/* proc_event_counts is used as the sequence number of the netlink message */
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-static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 };
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+/* local_event.count is used as the sequence number of the netlink message */
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+struct local_event {
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+	local_lock_t lock;
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+	__u32 count;
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+};
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+static DEFINE_PER_CPU(struct local_event, local_event) = {
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+	.lock = INIT_LOCAL_LOCK(lock),
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+};
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 static inline void send_msg(struct cn_msg *msg)
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 {
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-	preempt_disable();
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+	local_lock(&local_event.lock);
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-	msg->seq = __this_cpu_inc_return(proc_event_counts) - 1;
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+	msg->seq = __this_cpu_inc_return(local_event.count) - 1;
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 	((struct proc_event *)msg->data)->cpu = smp_processor_id();
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 	/*
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-	 * Preemption remains disabled during send to ensure the messages are
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-	 * ordered according to their sequence numbers.
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+	 * local_lock() disables preemption during send to ensure the messages
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+	 * are ordered according to their sequence numbers.
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 	 *
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 	 * If cn_netlink_send() fails, the data is not sent.
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 	 */
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 	cn_netlink_send(msg, 0, CN_IDX_PROC, GFP_NOWAIT);
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-	preempt_enable();
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+	local_unlock(&local_event.lock);
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 }
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 void proc_fork_connector(struct task_struct *task)