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Subject[PATCH 4.15 075/105] can: peak/pcie_fd: fix echo_skb is occupied! bug
Date
4.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Stephane Grosjean <s.grosjean@peak-system.com>

commit e6048a00cfd0863d32f53b226e0b9a3633fc3332 upstream.

This patch makes atomic the handling of the linux-can echo_skb array and
the network tx queue. This prevents from the "BUG! echo_skb is occupied!"
message to be printed by the linux-can core, in SMP environments.

Reported-by: Diana Burgess <diana@peloton-tech.com>
Signed-off-by: Stephane Grosjean <s.grosjean@peak-system.com>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/can/peak_canfd/peak_canfd.c | 12 ++++++------
drivers/net/can/peak_canfd/peak_pciefd_main.c | 8 ++++++--
2 files changed, 12 insertions(+), 8 deletions(-)

--- a/drivers/net/can/peak_canfd/peak_canfd.c
+++ b/drivers/net/can/peak_canfd/peak_canfd.c
@@ -262,7 +262,6 @@ static int pucan_handle_can_rx(struct pe

spin_lock_irqsave(&priv->echo_lock, flags);
can_get_echo_skb(priv->ndev, msg->client);
- spin_unlock_irqrestore(&priv->echo_lock, flags);

/* count bytes of the echo instead of skb */
stats->tx_bytes += cf_len;
@@ -271,6 +270,7 @@ static int pucan_handle_can_rx(struct pe
/* restart tx queue (a slot is free) */
netif_wake_queue(priv->ndev);

+ spin_unlock_irqrestore(&priv->echo_lock, flags);
return 0;
}

@@ -726,11 +726,6 @@ static netdev_tx_t peak_canfd_start_xmit
*/
should_stop_tx_queue = !!(priv->can.echo_skb[priv->echo_idx]);

- spin_unlock_irqrestore(&priv->echo_lock, flags);
-
- /* write the skb on the interface */
- priv->write_tx_msg(priv, msg);
-
/* stop network tx queue if not enough room to save one more msg too */
if (priv->can.ctrlmode & CAN_CTRLMODE_FD)
should_stop_tx_queue |= (room_left <
@@ -742,6 +737,11 @@ static netdev_tx_t peak_canfd_start_xmit
if (should_stop_tx_queue)
netif_stop_queue(ndev);

+ spin_unlock_irqrestore(&priv->echo_lock, flags);
+
+ /* write the skb on the interface */
+ priv->write_tx_msg(priv, msg);
+
return NETDEV_TX_OK;
}

--- a/drivers/net/can/peak_canfd/peak_pciefd_main.c
+++ b/drivers/net/can/peak_canfd/peak_pciefd_main.c
@@ -349,8 +349,12 @@ static irqreturn_t pciefd_irq_handler(in
priv->tx_pages_free++;
spin_unlock_irqrestore(&priv->tx_lock, flags);

- /* wake producer up */
- netif_wake_queue(priv->ucan.ndev);
+ /* wake producer up (only if enough room in echo_skb array) */
+ spin_lock_irqsave(&priv->ucan.echo_lock, flags);
+ if (!priv->ucan.can.echo_skb[priv->ucan.echo_idx])
+ netif_wake_queue(priv->ucan.ndev);
+
+ spin_unlock_irqrestore(&priv->ucan.echo_lock, flags);
}

/* re-enable Rx DMA transfer for this CAN */

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