Commit 4f7a07b8 authored by Ingo Molnar's avatar Ingo Molnar Committed by Linus Torvalds
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[PATCH] convert fs/9p/ to mutexes, fix locking bugs 



Convert fs/9p/mux.c from semaphore to mutex.

NOTE: fixed locking bugs in the process - the code was using semaphores
the other way around.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Cc: Eric Van Hensbergen <ericvh@ericvh.myip.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 9331b315

fs/9p/mux.c

+6 −5
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
#include <linux/poll.h>

#include <linux/kthread.h>

#include <linux/idr.h>

#include <linux/mutex.h>



#include "debug.h"

#include "v9fs.h"
@@ -110,7 +111,7 @@ static void v9fs_pollwait(struct file *filp, wait_queue_head_t * wait_address, 
static u16 v9fs_mux_get_tag(struct v9fs_mux_data *);

static void v9fs_mux_put_tag(struct v9fs_mux_data *, u16);



static DECLARE_MUTEX(v9fs_mux_task_lock);

static DEFINE_MUTEX(v9fs_mux_task_lock);

static struct workqueue_struct *v9fs_mux_wq;



static int v9fs_mux_num;
@@ -166,7 +167,7 @@ static int v9fs_mux_poll_start(struct v9fs_mux_data *m) 


	dprintk(DEBUG_MUX, "mux %p muxnum %d procnum %d\n", m, v9fs_mux_num,

		v9fs_mux_poll_task_num);

	up(&v9fs_mux_task_lock);

	mutex_lock(&v9fs_mux_task_lock);



	n = v9fs_mux_calc_poll_procs(v9fs_mux_num + 1);

	if (n > v9fs_mux_poll_task_num) {
@@ -225,7 +226,7 @@ static int v9fs_mux_poll_start(struct v9fs_mux_data *m) 
	}



	v9fs_mux_num++;

	down(&v9fs_mux_task_lock);

	mutex_unlock(&v9fs_mux_task_lock);



	return 0;

}
@@ -235,7 +236,7 @@ static void v9fs_mux_poll_stop(struct v9fs_mux_data *m) 
	int i;

	struct v9fs_mux_poll_task *vpt;



	up(&v9fs_mux_task_lock);

	mutex_lock(&v9fs_mux_task_lock);

	vpt = m->poll_task;

	list_del(&m->mux_list);

	for(i = 0; i < ARRAY_SIZE(m->poll_waddr); i++) {
@@ -252,7 +253,7 @@ static void v9fs_mux_poll_stop(struct v9fs_mux_data *m) 
		v9fs_mux_poll_task_num--;

	}

	v9fs_mux_num--;

	down(&v9fs_mux_task_lock);

	mutex_unlock(&v9fs_mux_task_lock);

}



/**