This is a note to let you know that I've just added the patch titled

    i2c-parport: Fix adapter list handling

to the 2.6.38-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     i2c-parport-fix-adapter-list-handling.patch
and it can be found in the queue-2.6.38 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From 56acc7a39ac4ac7638cdc32cd3d0832ebbc834e4 Mon Sep 17 00:00:00 2001
From: Jean Delvare <[email protected]>
Date: Sun, 1 May 2011 18:18:49 +0200
Subject: i2c-parport: Fix adapter list handling

From: Jean Delvare <[email protected]>

commit 56acc7a39ac4ac7638cdc32cd3d0832ebbc834e4 upstream.

Use a standard list with proper locking to handle the list of
adapters. Thankfully it only matters on systems with more than one
parallel port, which are very rare.

Thanks to Lukasz Kapiec for reporting the problem to me.

Signed-off-by: Jean Delvare <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 drivers/i2c/busses/i2c-parport.c |   27 ++++++++++++++-------------
 1 file changed, 14 insertions(+), 13 deletions(-)

--- a/drivers/i2c/busses/i2c-parport.c
+++ b/drivers/i2c/busses/i2c-parport.c
@@ -1,7 +1,7 @@
 /* ------------------------------------------------------------------------ *
  * i2c-parport.c I2C bus over parallel port                                 *
  * ------------------------------------------------------------------------ *
-   Copyright (C) 2003-2010 Jean Delvare <[email protected]>
+   Copyright (C) 2003-2011 Jean Delvare <[email protected]>
    
    Based on older i2c-philips-par.c driver
    Copyright (C) 1995-2000 Simon G. Vogl
@@ -33,6 +33,8 @@
 #include <linux/i2c-algo-bit.h>
 #include <linux/i2c-smbus.h>
 #include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
 #include "i2c-parport.h"
 
 /* ----- Device list ------------------------------------------------------ */
@@ -43,10 +45,11 @@ struct i2c_par {
        struct i2c_algo_bit_data algo_data;
        struct i2c_smbus_alert_setup alert_data;
        struct i2c_client *ara;
-       struct i2c_par *next;
+       struct list_head node;
 };
 
-static struct i2c_par *adapter_list;
+static LIST_HEAD(adapter_list);
+static DEFINE_MUTEX(adapter_list_lock);
 
 /* ----- Low-level parallel port access ----------------------------------- */
 
@@ -228,8 +231,9 @@ static void i2c_parport_attach (struct p
        }
 
        /* Add the new adapter to the list */
-       adapter->next = adapter_list;
-       adapter_list = adapter;
+       mutex_lock(&adapter_list_lock);
+       list_add_tail(&adapter->node, &adapter_list);
+       mutex_unlock(&adapter_list_lock);
         return;
 
 ERROR1:
@@ -241,11 +245,11 @@ ERROR0:
 
 static void i2c_parport_detach (struct parport *port)
 {
-       struct i2c_par *adapter, *prev;
+       struct i2c_par *adapter, *_n;
 
        /* Walk the list */
-       for (prev = NULL, adapter = adapter_list; adapter;
-            prev = adapter, adapter = adapter->next) {
+       mutex_lock(&adapter_list_lock);
+       list_for_each_entry_safe(adapter, _n, &adapter_list, node) {
                if (adapter->pdev->port == port) {
                        if (adapter->ara) {
                                parport_disable_irq(port);
@@ -259,14 +263,11 @@ static void i2c_parport_detach (struct p
                                
                        parport_release(adapter->pdev);
                        parport_unregister_device(adapter->pdev);
-                       if (prev)
-                               prev->next = adapter->next;
-                       else
-                               adapter_list = adapter->next;
+                       list_del(&adapter->node);
                        kfree(adapter);
-                       return;
                }
        }
+       mutex_unlock(&adapter_list_lock);
 }
 
 static struct parport_driver i2c_parport_driver = {


Patches currently in stable-queue which might be from [email protected] are

queue-2.6.38/i2c-parport-fix-adapter-list-handling.patch

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