NFC: Modified hci_transceive to become an asynchronous operation

This enables the completion callback to be called from a different
context, preventing a possible deadlock if the callback resulted in the
invocation of a nested call to the currently locked nfc_dev.
This is also more in line with the im_transceive nfc_ops for NFC Core or
NCI drivers which already behave asynchronously.

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

2 files changed, 8 insertions, 4 deletions

diff --git a/include/net/nfc/hci.h b/include/net/nfc/hci.h
index 54ba2caab4a6..6cee6e21fc46 100644
--- a/include/net/nfc/hci.h
+++ b/include/net/nfc/hci.h
@@ -38,8 +38,8 @@ struct nfc_hci_ops {
         int (*complete_target_discovered) (struct nfc_hci_dev *hdev, u8 gate,
                                            struct nfc_target *target);
         int (*data_exchange) (struct nfc_hci_dev *hdev,
-                              struct nfc_target *target,
-                              struct sk_buff *skb, struct sk_buff **res_skb);
+                              struct nfc_target *target, struct sk_buff *skb,
+                              data_exchange_cb_t cb, void *cb_context);
         int (*check_presence)(struct nfc_hci_dev *hdev,
                               struct nfc_target *target);
 };
@@ -103,6 +103,10 @@ struct nfc_hci_dev {
         u8 hw_mpw;
         u8 hw_software;
         u8 hw_bsid;
+
+        int async_cb_type;
+        data_exchange_cb_t async_cb;
+        void *async_cb_context;
 };
 
 /* hci device allocation */
diff --git a/include/net/nfc/shdlc.h b/include/net/nfc/shdlc.h
index 342427362989..fe5e19829352 100644
--- a/include/net/nfc/shdlc.h
+++ b/include/net/nfc/shdlc.h
@@ -34,8 +34,8 @@ struct nfc_shdlc_ops {
         int (*complete_target_discovered) (struct nfc_shdlc *shdlc, u8 gate,
                                            struct nfc_target *target);
         int (*data_exchange) (struct nfc_shdlc *shdlc,
-                              struct nfc_target *target,
-                              struct sk_buff *skb, struct sk_buff **res_skb);
+                              struct nfc_target *target, struct sk_buff *skb,
+                              data_exchange_cb_t cb, void *cb_context);
         int (*check_presence)(struct nfc_shdlc *shdlc,
                               struct nfc_target *target);
 };