1 files changed, 26 insertions, 6 deletions

diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c
index 3fd6e6651fbe..a3a54567bfba 100644
--- a/drivers/w1/w1_int.c
+++ b/drivers/w1/w1_int.c
@@ -29,7 +29,6 @@
 #include "w1_netlink.h"
 #include "w1_int.h"
 
-static u32 w1_ids = 1;
 static int w1_search_count = -1; /* Default is continual scan */
 module_param_named(search_count, w1_search_count, int, 0);
 
@@ -102,9 +101,10 @@ static void w1_free_dev(struct w1_master *dev)
 
 int w1_add_master_device(struct w1_bus_master *master)
 {
-        struct w1_master *dev;
+        struct w1_master *dev, *entry;
         int retval = 0;
         struct w1_netlink_msg msg;
+        int id, found;
 
         /* validate minimum functionality */
         if (!(master->touch_bit && master->reset_bus) &&
@@ -126,13 +126,33 @@ int w1_add_master_device(struct w1_bus_master *master)
                 master->set_pullup = NULL;
         }
 
-        dev = w1_alloc_dev(w1_ids++, w1_max_slave_count, w1_max_slave_ttl, &w1_master_driver, &w1_master_device);
-        if (!dev)
+        /* Lock until the device is added (or not) to w1_masters. */
+        mutex_lock(&w1_mlock);
+        /* Search for the first available id (starting at 1). */
+        id = 0;
+        do {
+                ++id;
+                found = 0;
+                list_for_each_entry(entry, &w1_masters, w1_master_entry) {
+                        if (entry->id == id) {
+                                found = 1;
+                                break;
+                        }
+                }
+        } while (found);
+
+        dev = w1_alloc_dev(id, w1_max_slave_count, w1_max_slave_ttl,
+                &w1_master_driver, &w1_master_device);
+        if (!dev) {
+                mutex_unlock(&w1_mlock);
                 return -ENOMEM;
+        }
 
         retval =  w1_create_master_attributes(dev);
-        if (retval)
+        if (retval) {
+                mutex_unlock(&w1_mlock);
                 goto err_out_free_dev;
+        }
 
         memcpy(dev->bus_master, master, sizeof(struct w1_bus_master));
 
@@ -144,10 +164,10 @@ int w1_add_master_device(struct w1_bus_master *master)
                 dev_err(&dev->dev,
                          "Failed to create new kernel thread. err=%d\n",
                          retval);
+                mutex_unlock(&w1_mlock);
                 goto err_out_rm_attr;
         }
 
-        mutex_lock(&w1_mlock);
         list_add(&dev->w1_master_entry, &w1_masters);
         mutex_unlock(&w1_mlock);