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>
diff --git a/drivers/nfc/pn544_hci.c b/drivers/nfc/pn544_hci.c
index d90aecf..a176d1f7 100644
--- a/drivers/nfc/pn544_hci.c
+++ b/drivers/nfc/pn544_hci.c
@@ -148,6 +148,9 @@
* < 0 if hardware error occured (e.g. i2c err)
* and prevents normal operation.
*/
+ int async_cb_type;
+ data_exchange_cb_t async_cb;
+ void *async_cb_context;
};
static void pn544_hci_platform_init(struct pn544_hci_info *info)
@@ -731,6 +734,26 @@
return r;
}
+#define PN544_CB_TYPE_READER_F 1
+
+static void pn544_hci_data_exchange_cb(void *context, struct sk_buff *skb,
+ int err)
+{
+ struct pn544_hci_info *info = context;
+
+ switch (info->async_cb_type) {
+ case PN544_CB_TYPE_READER_F:
+ if (err == 0)
+ skb_pull(skb, 1);
+ info->async_cb(info->async_cb_context, skb, err);
+ break;
+ default:
+ if (err == 0)
+ kfree_skb(skb);
+ break;
+ }
+}
+
#define MIFARE_CMD_AUTH_KEY_A 0x60
#define MIFARE_CMD_AUTH_KEY_B 0x61
#define MIFARE_CMD_HEADER 2
@@ -744,11 +767,11 @@
*/
static int pn544_hci_data_exchange(struct nfc_shdlc *shdlc,
struct nfc_target *target,
- struct sk_buff *skb,
- struct sk_buff **res_skb)
+ struct sk_buff *skb, data_exchange_cb_t cb,
+ void *cb_context)
{
+ struct pn544_hci_info *info = nfc_shdlc_get_clientdata(shdlc);
struct nfc_hci_dev *hdev = nfc_shdlc_get_hci_dev(shdlc);
- int r;
pr_info(DRIVER_DESC ": %s for gate=%d\n", __func__,
target->hci_reader_gate);
@@ -773,25 +796,29 @@
memcpy(data, uid, MIFARE_UID_LEN);
}
- return nfc_hci_send_cmd(hdev, target->hci_reader_gate,
- PN544_MIFARE_CMD,
- skb->data, skb->len, res_skb);
+ return nfc_hci_send_cmd_async(hdev,
+ target->hci_reader_gate,
+ PN544_MIFARE_CMD,
+ skb->data, skb->len,
+ cb, cb_context);
} else
return 1;
case PN544_RF_READER_F_GATE:
*skb_push(skb, 1) = 0;
*skb_push(skb, 1) = 0;
- r = nfc_hci_send_cmd(hdev, target->hci_reader_gate,
- PN544_FELICA_RAW,
- skb->data, skb->len, res_skb);
- if (r == 0)
- skb_pull(*res_skb, 1);
- return r;
+ info->async_cb_type = PN544_CB_TYPE_READER_F;
+ info->async_cb = cb;
+ info->async_cb_context = cb_context;
+
+ return nfc_hci_send_cmd_async(hdev, target->hci_reader_gate,
+ PN544_FELICA_RAW, skb->data,
+ skb->len,
+ pn544_hci_data_exchange_cb, info);
case PN544_RF_READER_JEWEL_GATE:
- return nfc_hci_send_cmd(hdev, target->hci_reader_gate,
- PN544_JEWEL_RAW_CMD,
- skb->data, skb->len, res_skb);
+ return nfc_hci_send_cmd_async(hdev, target->hci_reader_gate,
+ PN544_JEWEL_RAW_CMD, skb->data,
+ skb->len, cb, cb_context);
default:
return 1;
}
diff --git a/include/net/nfc/hci.h b/include/net/nfc/hci.h
index 54ba2ca..6cee6e2 100644
--- a/include/net/nfc/hci.h
+++ b/include/net/nfc/hci.h
@@ -38,8 +38,8 @@
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 @@
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 3424273..fe5e198 100644
--- a/include/net/nfc/shdlc.h
+++ b/include/net/nfc/shdlc.h
@@ -34,8 +34,8 @@
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);
};
diff --git a/net/nfc/hci/core.c b/net/nfc/hci/core.c
index e387c86..dc57e3d 100644
--- a/net/nfc/hci/core.c
+++ b/net/nfc/hci/core.c
@@ -537,13 +537,37 @@
{
}
+#define HCI_CB_TYPE_TRANSCEIVE 1
+
+static void hci_transceive_cb(void *context, struct sk_buff *skb, int err)
+{
+ struct nfc_hci_dev *hdev = context;
+
+ switch (hdev->async_cb_type) {
+ case HCI_CB_TYPE_TRANSCEIVE:
+ /*
+ * TODO: Check RF Error indicator to make sure data is valid.
+ * It seems that HCI cmd can complete without error, but data
+ * can be invalid if an RF error occured? Ignore for now.
+ */
+ if (err == 0)
+ skb_trim(skb, skb->len - 1); /* RF Err ind */
+
+ hdev->async_cb(hdev->async_cb_context, skb, err);
+ break;
+ default:
+ if (err == 0)
+ kfree_skb(skb);
+ break;
+ }
+}
+
static int hci_transceive(struct nfc_dev *nfc_dev, struct nfc_target *target,
struct sk_buff *skb, data_exchange_cb_t cb,
void *cb_context)
{
struct nfc_hci_dev *hdev = nfc_get_drvdata(nfc_dev);
int r;
- struct sk_buff *res_skb = NULL;
pr_debug("target_idx=%d\n", target->idx);
@@ -551,40 +575,37 @@
case NFC_HCI_RF_READER_A_GATE:
case NFC_HCI_RF_READER_B_GATE:
if (hdev->ops->data_exchange) {
- r = hdev->ops->data_exchange(hdev, target, skb,
- &res_skb);
+ r = hdev->ops->data_exchange(hdev, target, skb, cb,
+ cb_context);
if (r <= 0) /* handled */
break;
}
*skb_push(skb, 1) = 0; /* CTR, see spec:10.2.2.1 */
- r = nfc_hci_send_cmd(hdev, target->hci_reader_gate,
- NFC_HCI_WR_XCHG_DATA,
- skb->data, skb->len, &res_skb);
- /*
- * TODO: Check RF Error indicator to make sure data is valid.
- * It seems that HCI cmd can complete without error, but data
- * can be invalid if an RF error occured? Ignore for now.
- */
- if (r == 0)
- skb_trim(res_skb, res_skb->len - 1); /* RF Err ind */
+
+ hdev->async_cb_type = HCI_CB_TYPE_TRANSCEIVE;
+ hdev->async_cb = cb;
+ hdev->async_cb_context = cb_context;
+
+ r = nfc_hci_send_cmd_async(hdev, target->hci_reader_gate,
+ NFC_HCI_WR_XCHG_DATA, skb->data,
+ skb->len, hci_transceive_cb, hdev);
break;
default:
if (hdev->ops->data_exchange) {
- r = hdev->ops->data_exchange(hdev, target, skb,
- &res_skb);
+ r = hdev->ops->data_exchange(hdev, target, skb, cb,
+ cb_context);
if (r == 1)
r = -ENOTSUPP;
}
else
r = -ENOTSUPP;
+ break;
}
kfree_skb(skb);
- cb(cb_context, res_skb, r);
-
- return 0;
+ return r;
}
static int hci_check_presence(struct nfc_dev *nfc_dev,
diff --git a/net/nfc/hci/shdlc.c b/net/nfc/hci/shdlc.c
index 9357ba7..c63af7d 100644
--- a/net/nfc/hci/shdlc.c
+++ b/net/nfc/hci/shdlc.c
@@ -777,12 +777,13 @@
static int nfc_shdlc_data_exchange(struct nfc_hci_dev *hdev,
struct nfc_target *target,
struct sk_buff *skb,
- struct sk_buff **res_skb)
+ data_exchange_cb_t cb, void *cb_context)
{
struct nfc_shdlc *shdlc = nfc_hci_get_clientdata(hdev);
if (shdlc->ops->data_exchange)
- return shdlc->ops->data_exchange(shdlc, target, skb, res_skb);
+ return shdlc->ops->data_exchange(shdlc, target, skb, cb,
+ cb_context);
return -EPERM;
}