Hi Ursula,
> -----Original Message----- > From: Ursula Braun [mailto:ubr...@linux.vnet.ibm.com] > Sent: Thursday, October 05, 2017 2:54 AM > To: Parav Pandit <pa...@mellanox.com> > Cc: da...@davemloft.net; netdev@vger.kernel.org; linux- > r...@vger.kernel.org; linux-s...@vger.kernel.org; j...@linux.vnet.ibm.com; > schwidef...@de.ibm.com; heiko.carst...@de.ibm.com; > ra...@linux.vnet.ibm.com > Subject: Re: [PATCH net-next 01/10] net/smc: add missing dev_put > > > > On 10/02/2017 10:36 PM, Parav Pandit wrote: > > Hi Ursula, Dave, Hans, > > > >> -----Original Message----- > >> From: linux-rdma-ow...@vger.kernel.org [mailto:linux-rdma- > >> ow...@vger.kernel.org] On Behalf Of Ursula Braun > >> Sent: Wednesday, September 20, 2017 6:58 AM > >> To: da...@davemloft.net > >> Cc: netdev@vger.kernel.org; linux-r...@vger.kernel.org; linux- > >> s...@vger.kernel.org; j...@linux.vnet.ibm.com; schwidef...@de.ibm.com; > >> heiko.carst...@de.ibm.com; ra...@linux.vnet.ibm.com; > >> ubr...@linux.vnet.ibm.com > >> Subject: [PATCH net-next 01/10] net/smc: add missing dev_put > >> > >> From: Hans Wippel <hwip...@linux.vnet.ibm.com> > >> > >> 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 <hwip...@linux.vnet.ibm.com> > >> Signed-off-by: Ursula Braun <ubr...@linux.vnet.ibm.com> > >> --- > >> 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; This else part is not needed. You can fail the call as suggested above, inline below too. if (rc || !gid_addr.ndev) return -ENODEV; There must be valid netdev for RoCE gid. Rest code looks fine.
