On 2023/10/18 15:01, Dust Li wrote: > On Tue, Oct 17, 2023 at 08:42:34PM +0800, Guangguan Wang wrote: >> The ini->rc is used to store the last error happened when finding usable >> ism or rdma device in smc_listen_find_device, and is set by calling smc_ >> find_device_store_rc. Once the ini->rc is assigned to an none-zero value, >> the value can not be overwritten anymore. So the ini-rc should be set to >> the error reason only when an error actually occurs. >> >> When finding ISM/RDMA devices, device not found is not a real error, as >> not all machine have ISM/RDMA devices. Failures after device found, when >> initializing device or when initializing connection, is real errors, and >> should be store in ini->rc. >> >> SMC_CLC_DECL_DIFFPREFIX also is not a real error, as for SMC-RV2, it is >> not require same prefix. >> >> Signed-off-by: Guangguan Wang <guangguan.wang@xxxxxxxxxxxxxxxxx> >> --- >> net/smc/af_smc.c | 12 +++--------- >> 1 file changed, 3 insertions(+), 9 deletions(-) >> >> diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c >> index b3a67a168495..21e9c6ec4d01 100644 >> --- a/net/smc/af_smc.c >> +++ b/net/smc/af_smc.c >> @@ -2163,10 +2163,8 @@ static void smc_find_ism_v2_device_serv(struct smc_sock *new_smc, >> } >> mutex_unlock(&smcd_dev_list.mutex); >> >> - if (!ini->ism_dev[0]) { >> - smc_find_device_store_rc(SMC_CLC_DECL_NOSMCD2DEV, ini); >> + if (!ini->ism_dev[0]) > > Hi Guangguan, > > Generally, I think this is right. Fallback in one kind of device should > not be the final fallback reason. > > But what if we have more than one device and failed more than once, for > example: > Let's say we have an ISM device, a RDMA device. First we looked the ISM device > and failed during the initialization, we got a fallback reason A. Then we > looked for the RDMA device, and failed again, with another reason B. > Finally, we fallback to TCP. What should fallback reason be ? IMO, the order of finding devices is defined by preference. ISM v2, ISM v1, RDMA v2, RDMA v1, the former the prefer. I think it should return the most preferred device's failure reason if found and failed during the initialization. So, here should return the first reason(reason A). > > OTOH, SMC_CLC_DECL_NOSMCD2DEV is only used here. Removing it would mean > that we would never see SMC_CLC_DECL_NOSMCD2DEV in the fallback reason, > which makes it meaningless. > Is SMC_CLC_DECL_NOSMCD2DEV really necessary? There is no reason names SMC_CLC_DECL_NOSMCR2DEV. Thanks, Guangguan Wang > Best regards, > Dust > >> goto not_found; >> - } >> >> smc_ism_get_system_eid(&eid); >> if (!smc_clc_match_eid(ini->negotiated_eid, smc_v2_ext, >> @@ -2216,9 +2214,9 @@ static void smc_find_ism_v1_device_serv(struct smc_sock *new_smc, >> rc = smc_listen_ism_init(new_smc, ini); >> if (!rc) >> return; /* V1 ISM device found */ >> + smc_find_device_store_rc(rc, ini); >> >> not_found: >> - smc_find_device_store_rc(rc, ini); >> ini->smcd_version &= ~SMC_V1; >> ini->ism_dev[0] = NULL; >> ini->is_smcd = false; >> @@ -2267,10 +2265,8 @@ static void smc_find_rdma_v2_device_serv(struct smc_sock *new_smc, >> ini->smcrv2.saddr = new_smc->clcsock->sk->sk_rcv_saddr; >> ini->smcrv2.daddr = smc_ib_gid_to_ipv4(smc_v2_ext->roce); >> rc = smc_find_rdma_device(new_smc, ini); >> - if (rc) { >> - smc_find_device_store_rc(rc, ini); >> + if (rc) >> goto not_found; >> - } >> if (!ini->smcrv2.uses_gateway) >> memcpy(ini->smcrv2.nexthop_mac, pclc->lcl.mac, ETH_ALEN); >> >> @@ -2331,8 +2327,6 @@ static int smc_listen_find_device(struct smc_sock *new_smc, >> >> /* check for matching IP prefix and subnet length (V1) */ >> prfx_rc = smc_listen_prfx_check(new_smc, pclc); >> - if (prfx_rc) >> - smc_find_device_store_rc(prfx_rc, ini); >> >> /* get vlan id from IP device */ >> if (smc_vlan_by_tcpsk(new_smc->clcsock, ini)) >> -- >> 2.24.3 (Apple Git-128)