Hi! > The driver uses a private lock for synchronization of the xmit function and > the xmit completion handler, but since the NETIF_F_LLTX flag is not set, > the xmit function is also called with the xmit_lock held. > > On the other hand the completion handler uses the reverse locking order by > first taking the private lock and (in case that the tx queue had been > stopped) then the xmit_lock. > > Improve the locking by removing the private lock and using only the > xmit_lock for synchronization instead.
Do you have stmmac hardware to test on?
I believe something is very wrong with the locking there. In
particular... scheduling the stmmac_tx_timer() function to run often
should not do anything bad if locking is correct... but it breaks the
driver rather quickly. [Example patch below, needs applying to two
places in net-next.]
(Other possibility is that hardware races with the driver.)
Giuseppe, is there documentation available for the chip? Driver says
Documentation available at:
http://www.stlinux.com
but that page does not work for me...
404 Not Found
Code: NoSuchBucket
Message: The specified bucket does not exist
BucketName: www.stlinux.com
RequestId: 1C8A20CB99AE7F75
HostId:
ljPnqbEpyD8exct5MUgcDXSW8n+I67Yw0aejNhLuBQ0pqN0UCfiRBa3ztlOMngiXoSN+COX+VSw=
Best regards,
Pavel
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index ffbcd03..8040370 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1973,8 +1973,9 @@ static void stmmac_xmit_common(struct sk_buff *skb,
struct net_device *dev, int
*/
priv->tx_count_frames += nfrags + 1;
if (likely(priv->tx_coal_frames > priv->tx_count_frames)) {
- mod_timer(&priv->txtimer,
- STMMAC_COAL_TIMER(priv->tx_coal_timer));
+ if (priv->tx_count_frames == nfrags + 1)
+ mod_timer(&priv->txtimer,
+ STMMAC_COAL_TIMER(priv->tx_coal_timer));
} else {
priv->tx_count_frames = 0;
priv->hw->desc->set_tx_ic(desc);
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures)
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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