NFC: Use IDR library to assing NFC devices IDs

As a consequence the NFC device IDs won't be increasing all the time,
as IDR provides the first available ID.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 16 insertions, 7 deletions

diff --git a/net/nfc/core.c b/net/nfc/core.c
index f1c33f233311..e94363dbbf4a 100644
--- a/net/nfc/core.c
+++ b/net/nfc/core.c
@@ -40,6 +40,9 @@
 int nfc_devlist_generation;
 DEFINE_MUTEX(nfc_devlist_mutex);
 
+/* NFC device ID bitmap */
+static DEFINE_IDA(nfc_index_ida);
+
 /**
  * nfc_dev_up - turn on the NFC device
  *
@@ -760,7 +763,6 @@ struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops,
                                     u32 supported_protocols,
                                     int tx_headroom, int tx_tailroom)
 {
-        static atomic_t dev_no = ATOMIC_INIT(0);
         struct nfc_dev *dev;
 
         if (!ops->start_poll || !ops->stop_poll || !ops->activate_target ||
@@ -774,11 +776,6 @@ struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops,
         if (!dev)
                 return NULL;
 
-        dev->dev.class = &nfc_class;
-        dev->idx = atomic_inc_return(&dev_no) - 1;
-        dev_set_name(&dev->dev, "nfc%d", dev->idx);
-        device_initialize(&dev->dev);
-
         dev->ops = ops;
         dev->supported_protocols = supported_protocols;
         dev->tx_headroom = tx_headroom;
@@ -814,6 +811,14 @@ int nfc_register_device(struct nfc_dev *dev)
 
         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 
+        dev->idx = ida_simple_get(&nfc_index_ida, 0, 0, GFP_KERNEL);
+        if (dev->idx < 0)
+                return dev->idx;
+
+        dev->dev.class = &nfc_class;
+        dev_set_name(&dev->dev, "nfc%d", dev->idx);
+        device_initialize(&dev->dev);
+
         mutex_lock(&nfc_devlist_mutex);
         nfc_devlist_generation++;
         rc = device_add(&dev->dev);
@@ -842,10 +847,12 @@ EXPORT_SYMBOL(nfc_register_device);
  */
 void nfc_unregister_device(struct nfc_dev *dev)
 {
-        int rc;
+        int rc, id;
 
         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 
+        id = dev->idx;
+
         mutex_lock(&nfc_devlist_mutex);
         nfc_devlist_generation++;
 
@@ -864,6 +871,8 @@ void nfc_unregister_device(struct nfc_dev *dev)
                 pr_debug("The userspace won't be notified that the device %s was removed\n",
                          dev_name(&dev->dev));
 
+        ida_simple_remove(&nfc_index_ida, id);
+
 }
 EXPORT_SYMBOL(nfc_unregister_device);