2011-09-22 08:38:48

by ilanelias78

Subject: [PATCH] NFC: protect nci_data_exchange transactions

From: Ilan Elias <[email protected]>

Protect 'cb' and 'cb_context' arguments in nci_data_exchange.
In fact, this implements a queue with max length of 1 data
exchange transactions in parallel.

Signed-off-by: Ilan Elias <[email protected]>
---
include/net/nfc/nci_core.h | 1 +
net/nfc/nci/core.c | 10 +++++++++-
net/nfc/nci/data.c | 2 ++
net/nfc/nci/ntf.c | 2 +-
4 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/include/net/nfc/nci_core.h b/include/net/nfc/nci_core.h
index 2563f3a..b8b4bbd 100644
--- a/include/net/nfc/nci_core.h
+++ b/include/net/nfc/nci_core.h
@@ -40,6 +40,7 @@ enum {
NCI_UP,
NCI_DISCOVERY,
NCI_POLL_ACTIVE,
+ NCI_DATA_EXCHANGE,
};

/* NCI timeouts */
diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c
index 895e5fd..2fcbe58 100644
--- a/net/nfc/nci/core.c
+++ b/net/nfc/nci/core.c
@@ -452,6 +452,7 @@ static int nci_data_exchange(struct nfc_dev *nfc_dev, __u32 target_idx,
void *cb_context)
{
struct nci_dev *ndev = nfc_get_drvdata(nfc_dev);
+ int rc;

nfc_dbg("entry, target_idx %d, len %d", target_idx, skb->len);

@@ -460,11 +461,18 @@ static int nci_data_exchange(struct nfc_dev *nfc_dev, __u32 target_idx,
return -EINVAL;
}

+ if (test_and_set_bit(NCI_DATA_EXCHANGE, &ndev->flags))
+ return -EBUSY;
+
/* store cb and context to be used on receiving data */
ndev->data_exchange_cb = cb;
ndev->data_exchange_cb_context = cb_context;

- return nci_send_data(ndev, ndev->conn_id, skb);
+ rc = nci_send_data(ndev, ndev->conn_id, skb);
+ if (rc)
+ clear_bit(NCI_DATA_EXCHANGE, &ndev->flags);
+
+ return rc;
}

static struct nfc_ops nci_nfc_ops = {
diff --git a/net/nfc/nci/data.c b/net/nfc/nci/data.c
index 141790a..e5ed90f 100644
--- a/net/nfc/nci/data.c
+++ b/net/nfc/nci/data.c
@@ -54,6 +54,8 @@ void nci_data_exchange_complete(struct nci_dev *ndev,
/* no waiting callback, free skb */
kfree_skb(skb);
}
+
+ clear_bit(NCI_DATA_EXCHANGE, &ndev->flags);
}

/* ----------------- NCI TX Data ----------------- */
diff --git a/net/nfc/nci/ntf.c b/net/nfc/nci/ntf.c
index 8dd7535..96633f5 100644
--- a/net/nfc/nci/ntf.c
+++ b/net/nfc/nci/ntf.c
@@ -215,7 +215,7 @@ static void nci_rf_deactivate_ntf_packet(struct nci_dev *ndev,
}

/* complete the data exchange transaction, if exists */
- if (ndev->data_exchange_cb)
+ if (test_bit(NCI_DATA_EXCHANGE, &ndev->flags))
nci_data_exchange_complete(ndev, NULL, -EIO);
}

--
1.7.0.4

2011-09-26 21:03:25

by Lauro Ramos Venancio

Subject: Re: [PATCH] NFC: protect nci_data_exchange transactions

2011/9/22 <[email protected]>:
> From: Ilan Elias <[email protected]>
>
> Protect 'cb' and 'cb_context' arguments in nci_data_exchange.
> In fact, this implements a queue with max length of 1 data
> exchange transactions in parallel.
>
> Signed-off-by: Ilan Elias <[email protected]>
Acked-by: Lauro Ramos Venancio <[email protected]>