This is a note to let you know that I've just added the patch titled
staging: vt6655: vnt_tx_packet Correct TX order of OWNED_BY_NIC
to the 4.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
staging-vt6655-vnt_tx_packet-correct-tx-order-of-owned_by_nic.patch
and it can be found in the queue-4.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From d65d2b25d2761153390df8026cca1a528d9b6c5a Mon Sep 17 00:00:00 2001
From: Malcolm Priestley <[email protected]>
Date: Tue, 21 Apr 2015 22:33:00 +0100
Subject: staging: vt6655: vnt_tx_packet Correct TX order of OWNED_BY_NIC
From: Malcolm Priestley <[email protected]>
commit d65d2b25d2761153390df8026cca1a528d9b6c5a upstream.
The state of m_td0TD0.f1Owner should change after the buff_addr
has been filled otherwise the device grabs the buffer too early.
m_td0TD0.f1Owner is protected by memory barriers on both sides
of change.
iTDUsed is best incremented after MACvTransmit.
It appears that f1Owner actually polls to do the memory transfer.
A back port patch will be needed for v3.19
Signed-off-by: Malcolm Priestley <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/staging/vt6655/device_main.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
--- a/drivers/staging/vt6655/device_main.c
+++ b/drivers/staging/vt6655/device_main.c
@@ -1203,14 +1203,6 @@ static int vnt_tx_packet(struct vnt_priv
if (dma_idx == TYPE_AC0DMA)
head_td->pTDInfo->byFlags = TD_FLAGS_NETIF_SKB;
- priv->iTDUsed[dma_idx]++;
-
- /* Take ownership */
- wmb();
- head_td->m_td0TD0.f1Owner = OWNED_BY_NIC;
-
- /* get Next */
- wmb();
priv->apCurrTD[dma_idx] = head_td->next;
spin_unlock_irqrestore(&priv->lock, flags);
@@ -1231,11 +1223,18 @@ static int vnt_tx_packet(struct vnt_priv
head_td->buff_addr = cpu_to_le32(head_td->pTDInfo->skb_dma);
+ /* Poll Transmit the adapter */
+ wmb();
+ head_td->m_td0TD0.f1Owner = OWNED_BY_NIC;
+ wmb(); /* second memory barrier */
+
if (head_td->pTDInfo->byFlags & TD_FLAGS_NETIF_SKB)
MACvTransmitAC0(priv->PortOffset);
else
MACvTransmit0(priv->PortOffset);
+ priv->iTDUsed[dma_idx]++;
+
spin_unlock_irqrestore(&priv->lock, flags);
return 0;
Patches currently in stable-queue which might be from [email protected] are
queue-4.0/staging-vt6655-vnt_tx_packet-correct-tx-order-of-owned_by_nic.patch
queue-4.0/staging-vt6655-device_free_tx_buf-use-only-ieee80211_tx_status_irqsafe.patch
queue-4.0/staging-vt6656-use-ieee80211_tx_info-to-select-packet-type.patch
queue-4.0/staging-vt6655-implement-ieee80211_tx_stat_noack_transmitted.patch
queue-4.0/staging-vt6655-fix-80211-control-and-management-status-reporting.patch
queue-4.0/staging-vt6655-lock-macvwritebssidaddress.patch
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