Re: [PATCH] net: arc_emac: fix arc_emac_rx() error paths

From: Florian Fainelli
Date: Tue Dec 19 2017 - 13:33:48 EST

On 12/19/2017 07:49 AM, Alexander Kochetkov wrote:
>> 19 ÐÐÐ. 2017 Ð., Ð 18:22, David Miller <davem@xxxxxxxxxxxxx> ÐÐÐÐÑÐÐ(Ð):
>> From: Alexander Kochetkov <al.kochet@xxxxxxxxx>
>> Date: Fri, 15 Dec 2017 20:20:06 +0300
>>> arc_emac_rx() has some issues found by code review.
>>> In case netdev_alloc_skb_ip_align() or dma_map_single() failure
>>> rx fifo entry will not be returned to EMAC.
>>> In case dma_map_single() failure previously allocated skb became
>>> lost to driver. At the same time address of newly allocated skb
>>> will not be provided to EMAC.
>>> Signed-off-by: Alexander Kochetkov <al.kochet@xxxxxxxxx>
>> This patch adds quite a few bugs, here is one which shows this is not
>> functionally tested:
> May be I donât understand correctly, but I donât see bug here.
> Wrong dma mapping usage should immediately manifest itself (kernel
> instability, koops and so on). The patch was tested on rk3188 and work fine for me.
> Also I did simulations of netdev_alloc_skb_ip_align() and dma_map_single()
> faults and can confirm that new error handling work.
> Could someone else with ARC EMAC test the patch? I would be very grateful for the help.
> Florian or Eric, can you test it on your hardware?

I don't actually have access to this hardware, the only change I did to
this driver was to use a standard Device Tree property :)