On 10/02/2017 10:36 PM, Parav Pandit wrote:
> Hi Ursula, Dave, Hans,
>
>> -----Original Message-----
>> From: [email protected] [mailto:linux-rdma-
>> [email protected]] On Behalf Of Ursula Braun
>> Sent: Wednesday, September 20, 2017 6:58 AM
>> To: [email protected]
>> Cc: [email protected]; [email protected]; linux-
>> [email protected]; [email protected]; [email protected];
>> [email protected]; [email protected];
>> [email protected]
>> Subject: [PATCH net-next 01/10] net/smc: add missing dev_put
>>
>> From: Hans Wippel <[email protected]>
>>
>> In the infiniband part, SMC currently uses get_netdev which calls dev_hold on
>> the returned net device. However, the SMC code never calls dev_put on that
>> net
>> device resulting in a wrong reference count.
>>
>> This patch adds a dev_put after the usage of the net device to fix the issue.
>>
>> Signed-off-by: Hans Wippel <[email protected]>
>> Signed-off-by: Ursula Braun <[email protected]>
>> ---
>> net/smc/smc_ib.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c index
>> 547e0e113b17..0b5852299158 100644
>> --- a/net/smc/smc_ib.c
>> +++ b/net/smc/smc_ib.c
>> @@ -380,6 +380,7 @@ static int smc_ib_fill_gid_and_mac(struct smc_ib_device
>> *smcibdev, u8 ibport)
>> ndev = smcibdev->ibdev->get_netdev(smcibdev->ibdev, ibport);
>> if (ndev) {
>> memcpy(&smcibdev->mac, ndev->dev_addr, ETH_ALEN);
>> + dev_put(ndev);
>
> I am sorry for providing late comments. smc_ib_fill_gid_and_mac() is not
> coded correctly.
> Few fixes are needed.
> 1. ULP such as SMC should not open code/deference any function pointer like
> get_netdev() of the IB device.
> 2. Replace ib_query_gid(..., NULL)
> With
> ib_query_gid(..., gid_attr);
>
> Use gid_attr.ndev to get the MAC address.
> Do dev_put(gid_attr.ndev);
>
> Code should look like below,
>
> struct ib_gid_attr gid_attr;
>
> rc = ib_query_gid(..., &gid_attr);
> if (rc || !gid_addr.ndev)
> return -ENODEV;
> else
> memcpy(smcibdev->mac, ndev->dev_addr, ETH_ALEN);
> dev_put(gid_addr.ndev);
>
Thanks, Parav!
Following your fix ideas I plan to change the function into this one:
static int smc_ib_fill_gid_and_mac(struct smc_ib_device *smcibdev, u8 ibport)
{
struct ib_gid_attr gattr;
int rc;
rc = ib_query_gid(smcibdev->ibdev, ibport, 0,
&smcibdev->gid[ibport - 1], &gattr);
/* the SMC protocol requires specification of the roce MAC address;
* if net_device cannot be determined, it can be derived from gid 0
*/
if (rc)
return rc;
if (gattr.ndev) {
memcpy(&smcibdev->mac, gattr.ndev->dev_addr, ETH_ALEN);
dev_put(gattr.ndev);
} else {
memcpy(&smcibdev->mac[ibport - 1][0],
&smcibdev->gid[ibport - 1].raw[8], 3);
memcpy(&smcibdev->mac[ibport - 1][3],
&smcibdev->gid[ibport - 1].raw[13], 3);
smcibdev->mac[ibport - 1][0] &= ~0x02;
}
return 0;
}
If you agree, I will submit the corresponding patch including a
Suggested-by: Parav Pandit <[email protected]>
Regards, Ursula
