From f3e8fb552789f4845e60b11c47b676d14b9488e5 Mon Sep 17 00:00:00 2001 From: Eric Lapuyade Date: Tue, 11 Sep 2012 10:43:50 +0200 Subject: 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 Signed-off-by: Samuel Ortiz --- net/nfc/hci/core.c | 57 ++++++++++++++++++++++++++++++++++++----------------- net/nfc/hci/shdlc.c | 5 +++-- 2 files changed, 42 insertions(+), 20 deletions(-) (limited to 'net/nfc') 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; } -- cgit v1.2.3