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authorRichard Cochran <richardcochran@gmail.com>2011-10-20 20:49:15 -0400
committerDavid S. Miller <davem@davemloft.net>2011-10-24 02:54:50 -0400
commitda92b194cc36b5dc1fbd85206aeeffd80bee0c39 (patch)
tree375ead604156d8a8afc5ecef8d76415e999ce903 /include/linux/skbuff.h
parentf7ff19871bb4a3451e1ca2cf660bf633018cfbec (diff)
net: hold sock reference while processing tx timestamps
The pair of functions, * skb_clone_tx_timestamp() * skb_complete_tx_timestamp() were designed to allow timestamping in PHY devices. The first function, called during the MAC driver's hard_xmit method, identifies PTP protocol packets, clones them, and gives them to the PHY device driver. The PHY driver may hold onto the packet and deliver it at a later time using the second function, which adds the packet to the socket's error queue. As pointed out by Johannes, nothing prevents the socket from disappearing while the cloned packet is sitting in the PHY driver awaiting a timestamp. This patch fixes the issue by taking a reference on the socket for each such packet. In addition, the comments regarding the usage of these function are expanded to highlight the rule that PHY drivers must use skb_complete_tx_timestamp() to release the packet, in order to release the socket reference, too. These functions first appeared in v2.6.36. Reported-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Richard Cochran <richard.cochran@omicron.at> Cc: <stable@vger.kernel.org> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Reviewed-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/skbuff.h')
-rw-r--r--include/linux/skbuff.h7
1 files changed, 6 insertions, 1 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 8bd383caa363..0f966460a345 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2020,8 +2020,13 @@ static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
2020/** 2020/**
2021 * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps 2021 * skb_complete_tx_timestamp() - deliver cloned skb with tx timestamps
2022 * 2022 *
2023 * PHY drivers may accept clones of transmitted packets for
2024 * timestamping via their phy_driver.txtstamp method. These drivers
2025 * must call this function to return the skb back to the stack, with
2026 * or without a timestamp.
2027 *
2023 * @skb: clone of the the original outgoing packet 2028 * @skb: clone of the the original outgoing packet
2024 * @hwtstamps: hardware time stamps 2029 * @hwtstamps: hardware time stamps, may be NULL if not available
2025 * 2030 *
2026 */ 2031 */
2027void skb_complete_tx_timestamp(struct sk_buff *skb, 2032void skb_complete_tx_timestamp(struct sk_buff *skb,