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authorEric Lapuyade <eric.lapuyade@linux.intel.com>2012-09-11 10:43:50 +0200
committerSamuel Ortiz <sameo@linux.intel.com>2012-09-25 00:17:25 +0200
commitf3e8fb552789f4845e60b11c47b676d14b9488e5 (patch)
tree8fde55db141d361952cbb190d9e59231e143157b /net/nfc
parente4c4789e55327e5f2bd6cafcccd46f9b6251bbc3 (diff)
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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>
Diffstat (limited to 'net/nfc')
-rw-r--r--net/nfc/hci/core.c57
-rw-r--r--net/nfc/hci/shdlc.c5
2 files changed, 42 insertions, 20 deletions
diff --git a/net/nfc/hci/core.c b/net/nfc/hci/core.c
index e387c86e0cc..dc57e3dc15a 100644
--- a/net/nfc/hci/core.c
+++ b/net/nfc/hci/core.c
@@ -537,13 +537,37 @@ static void hci_deactivate_target(struct nfc_dev *nfc_dev,
{
}
+#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 @@ static int hci_transceive(struct nfc_dev *nfc_dev, struct nfc_target *target,
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 9357ba7362f..c63af7d3e85 100644
--- a/net/nfc/hci/shdlc.c
+++ b/net/nfc/hci/shdlc.c
@@ -777,12 +777,13 @@ static int nfc_shdlc_complete_target_discovered(struct nfc_hci_dev *hdev,
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;
}