This patch fixes a regression that was introduced by
commit 0a5f384677
davinci_emac: Add Carrier Link OK check in Davinci RX Handler
Said commit adds a check whether the carrier link is ok. If the link is
not ok, the skb is freed and no new dma descriptor added to the rx dma
channel. This causes trouble during initialization when the carrier
status has not yet been updated. If a lot of packets are received while
netif_carrier_ok returns false, all dma descriptors are freed and the
rx dma transfer is stopped.
The bug occurs when the board is connected to a network with lots of
traffic and the ifconfig down/up is done, e.g., when reconfiguring
the interface with DHCP.
The bug can be reproduced by flood pinging the davinci board while doing
ifconfig eth0 down
ifconfig eth0 up
on the board.
After that, the rx path stops working and the overrun value reported
by ifconfig is counting up.
This patch reverts commit 0a5f384677
and instead issues warnings only if cpdma_chan_submit returns -ENOMEM.
Signed-off-by: Christian Riesch <christian.riesch@omicron.at>
Cc: <stable@vger.kernel.org>
Cc: Hegde, Vinay <vinay.hegde@ti.com>
Cc: Cyril Chemparathy <cyril@ti.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Rajashekhara, Sudhakar <sudhakar.raj@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
PTR_ERR should be called before its argument is cleared.
The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@@
expression e,e1;
constant c;
@@
*e = c
... when != e = e1
when != &e
when != true IS_ERR(e)
*PTR_ERR(e)
// </smpl>
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Reported-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
The driver uses a shared pool for both rx and tx descriptors.
During open it queues fixed number of 128 descriptors for receive
packets. For each received packet it tries to queue another
descriptor. If this fails the descriptor is lost for rx.
The driver has no limitation on tx descriptors to use, so it
can happen during a nmap / ping -f attack that the driver
allocates all descriptors for tx and looses all rx descriptors.
The driver stops working then.
To fix this limit the number of tx descriptors used to half of
the descriptors available, the rx path uses the other half.
Tested on a custom board using nmap / ping -f to the board from
two different hosts.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
