NFC: nfc_targets_found() should accept zero target found

The semantics for a zero target found event is that the polling operation
could not complete.

Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 13 insertions, 6 deletions

diff --git a/net/nfc/core.c b/net/nfc/core.c
index 94ccf07374a5..749ee48d3600 100644
--- a/net/nfc/core.c
+++ b/net/nfc/core.c
@@ -560,6 +560,8 @@ EXPORT_SYMBOL(nfc_alloc_recv_skb);
  * The device driver must call this function when one or many nfc targets
  * are found. After calling this function, the device driver must stop
  * polling for targets.
+ * NOTE: This function can be called with targets=NULL and n_targets=0 to
+ * notify a driver error, meaning that the polling operation cannot complete.
  * IMPORTANT: this function must not be called from an atomic context.
  * In addition, it must also not be called from a context that would prevent
  * the NFC Core to call other nfc ops entry point concurrently.
@@ -586,13 +588,18 @@ int nfc_targets_found(struct nfc_dev *dev,
         dev->targets_generation++;
 
         kfree(dev->targets);
-        dev->targets = kmemdup(targets, n_targets * sizeof(struct nfc_target),
-                               GFP_ATOMIC);
+        dev->targets = NULL;
 
-        if (!dev->targets) {
-                dev->n_targets = 0;
-                device_unlock(&dev->dev);
-                return -ENOMEM;
+        if (targets) {
+                dev->targets = kmemdup(targets,
+                                       n_targets * sizeof(struct nfc_target),
+                                       GFP_ATOMIC);
+
+                if (!dev->targets) {
+                        dev->n_targets = 0;
+                        device_unlock(&dev->dev);
+                        return -ENOMEM;
+                }
         }
 
         dev->n_targets = n_targets;