uids: Prevent tear down race

[safe/jmp/linux-2.6] / drivers / w1 / w1_int.c

diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c
index 9d723ef..4a46ed5 100644 (file)
--- a/drivers/w1/w1_int.c
+++ b/drivers/w1/w1_int.c
@@ -29,7 +29,8 @@
 #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);
 
 static int w1_enable_pullup = 1;
 module_param_named(enable_pullup, w1_enable_pullup, int, 0);
@@ -62,8 +63,8 @@ static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
        dev->initialized        = 0;
        dev->id                 = id;
        dev->slave_ttl          = slave_ttl;
+       dev->search_count       = w1_search_count;
        dev->enable_pullup      = w1_enable_pullup;
-        dev->search_count      = -1; /* continual scan */
 
        /* 1 for w1_process to decrement
         * 1 for __w1_remove_master_device to decrement
@@ -74,8 +75,7 @@ static struct w1_master * w1_alloc_dev(u32 id, int slave_count, int slave_ttl,
        mutex_init(&dev->mutex);
 
        memcpy(&dev->dev, device, sizeof(struct device));
-       snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id),
-                 "w1_bus_master%u", dev->id);
+       dev_set_name(&dev->dev, "w1_bus_master%u", dev->id);
        snprintf(dev->name, sizeof(dev->name), "w1_bus_master%u", dev->id);
 
        dev->driver = driver;
@@ -100,9 +100,10 @@ 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) &&
@@ -124,13 +125,33 @@ 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));
 
@@ -142,10 +163,10 @@ 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);