[11/33] NFC: nfc_targets_found() should accept zero target found

Commit Message

Samuel Ortiz July 6, 2012, 8:09 p.m. UTC

From: Eric Lapuyade <[e-mail]>

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

Signed-off-by: Eric Lapuyade <[e-mail]>
Signed-off-by: Samuel Ortiz <[e-mail]>
---
 net/nfc/core.c |   19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

Patch

diff --git a/net/nfc/core.c b/net/nfc/core.c
index 94ccf07..749ee48 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;