From: Rusty Russell <rusty@rustcorp.com.au>
To: NeilBrown <neilb@cse.unsw.edu.au>
Cc: torvalds@transmeta.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Add module_kernel_thread for threads that live in modules.
Date: Mon, 16 Jun 2003 16:50:33 +1000
Message-Id: <20030616065058.D1C9E2C08A@lists.samba.org>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1331
Lines: 41

Hi Neil,

	There are several problems with this patch.  Ignoring the fact
that you use __module_get.  Firstly, you bump the module count
permentantly while the thread is running: how does it ever get
unloaded?  Secondly, modprobe becomes your parent.

	There have been ambitious attempts to do a nice "thread
creation and stopping" interface before.  Given the delicate logic
involved in shutting threads down, I think this makes sense.  Maybe
something like: 

/* Struct which identifies a kernel thread, handed to creator and
   thread. */
struct kthread
{
	int pid;
	int should_die; /* Thread should exit when this is set. */

	/* User supplied arg... */
	void *arg;
};

struct kthread *create_thread(int (*fn)(struct kthread*), void *arg, 
			      unsigned long flags,
			      const char *namefmt, ...);
void cleanup_thread(struct kthread *);

create_thread would use keventd to start the thread, and stop_thread
would tell keventd to set should_die, wmb(), wake it up, and
sys_wait() for it.

Thoughts?
Rusty.
--
  Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
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