From 8e316b9e7260cbc61974c2558733dab5de949399 Mon Sep 17 00:00:00 2001 From: Ursula Braun Date: Mon, 21 Oct 2019 16:13:11 +0200 Subject: [PATCH] net/smc: improve link group freeing Usually link groups are freed delayed to enable quick connection creation for a follow-on SMC socket. Terminated link groups are freed faster. This patch makes sure, fast schedule of link group freeing is not rescheduled by a delayed schedule. And it makes sure link group freeing is not rescheduled, if the real freeing is already running. Signed-off-by: Ursula Braun Signed-off-by: Karsten Graul Signed-off-by: Jakub Kicinski --- net/smc/smc_core.c | 47 +++++++++++++++++++++++++++++----------------- net/smc/smc_core.h | 2 ++ 2 files changed, 32 insertions(+), 17 deletions(-) diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c index 1f58cd82928c..e7e9dbcd7d8b 100644 --- a/net/smc/smc_core.c +++ b/net/smc/smc_core.c @@ -61,14 +61,21 @@ static void smc_lgr_schedule_free_work(struct smc_link_group *lgr) * creation. For client use a somewhat higher removal delay time, * otherwise there is a risk of out-of-sync link groups. */ - mod_delayed_work(system_wq, &lgr->free_work, - (!lgr->is_smcd && lgr->role == SMC_CLNT) ? - SMC_LGR_FREE_DELAY_CLNT : SMC_LGR_FREE_DELAY_SERV); + if (!lgr->freeing && !lgr->freefast) { + mod_delayed_work(system_wq, &lgr->free_work, + (!lgr->is_smcd && lgr->role == SMC_CLNT) ? + SMC_LGR_FREE_DELAY_CLNT : + SMC_LGR_FREE_DELAY_SERV); + } } void smc_lgr_schedule_free_work_fast(struct smc_link_group *lgr) { - mod_delayed_work(system_wq, &lgr->free_work, SMC_LGR_FREE_DELAY_FAST); + if (!lgr->freeing && !lgr->freefast) { + lgr->freefast = 1; + mod_delayed_work(system_wq, &lgr->free_work, + SMC_LGR_FREE_DELAY_FAST); + } } /* Register connection's alert token in our lookup structure. @@ -171,10 +178,15 @@ static void smc_lgr_free_work(struct work_struct *work) struct smc_link_group, free_work); spinlock_t *lgr_lock; + struct smc_link *lnk; bool conns; smc_lgr_list_head(lgr, &lgr_lock); spin_lock_bh(lgr_lock); + if (lgr->freeing) { + spin_unlock_bh(lgr_lock); + return; + } read_lock_bh(&lgr->conns_lock); conns = RB_EMPTY_ROOT(&lgr->conns_all); read_unlock_bh(&lgr->conns_lock); @@ -183,29 +195,27 @@ static void smc_lgr_free_work(struct work_struct *work) return; } list_del_init(&lgr->list); /* remove from smc_lgr_list */ - spin_unlock_bh(lgr_lock); + lnk = &lgr->lnk[SMC_SINGLE_LINK]; if (!lgr->is_smcd && !lgr->terminating) { - struct smc_link *lnk = &lgr->lnk[SMC_SINGLE_LINK]; - /* try to send del link msg, on error free lgr immediately */ if (lnk->state == SMC_LNK_ACTIVE && !smc_link_send_delete(lnk)) { /* reschedule in case we never receive a response */ smc_lgr_schedule_free_work(lgr); + spin_unlock_bh(lgr_lock); return; } } + lgr->freeing = 1; /* this instance does the freeing, no new schedule */ + spin_unlock_bh(lgr_lock); + cancel_delayed_work(&lgr->free_work); - if (!delayed_work_pending(&lgr->free_work)) { - struct smc_link *lnk = &lgr->lnk[SMC_SINGLE_LINK]; - - if (!lgr->is_smcd && lnk->state != SMC_LNK_INACTIVE) - smc_llc_link_inactive(lnk); - if (lgr->is_smcd) - smc_ism_signal_shutdown(lgr); - smc_lgr_free(lgr); - } + if (!lgr->is_smcd && lnk->state != SMC_LNK_INACTIVE) + smc_llc_link_inactive(lnk); + if (lgr->is_smcd) + smc_ism_signal_shutdown(lgr); + smc_lgr_free(lgr); } /* create a new SMC link group */ @@ -233,6 +243,9 @@ static int smc_lgr_create(struct smc_sock *smc, struct smc_init_info *ini) } lgr->is_smcd = ini->is_smcd; lgr->sync_err = 0; + lgr->terminating = 0; + lgr->freefast = 0; + lgr->freeing = 0; lgr->vlan_id = ini->vlan_id; rwlock_init(&lgr->sndbufs_lock); rwlock_init(&lgr->rmbs_lock); @@ -513,7 +526,7 @@ static void __smc_lgr_terminate(struct smc_link_group *lgr) read_unlock_bh(&lgr->conns_lock); if (!lgr->is_smcd) wake_up(&lgr->lnk[SMC_SINGLE_LINK].wr_reg_wait); - smc_lgr_schedule_free_work(lgr); + smc_lgr_schedule_free_work_fast(lgr); } /* unlink and terminate link group */ diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h index c00ac61dc129..12c2818b293f 100644 --- a/net/smc/smc_core.h +++ b/net/smc/smc_core.h @@ -204,6 +204,8 @@ struct smc_link_group { struct delayed_work free_work; /* delayed freeing of an lgr */ u8 sync_err : 1; /* lgr no longer fits to peer */ u8 terminating : 1;/* lgr is terminating */ + u8 freefast : 1; /* free worker scheduled fast */ + u8 freeing : 1; /* lgr is being freed */ bool is_smcd; /* SMC-R or SMC-D */ union { -- GitLab