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| author | Wen Gu <guwen@linux.alibaba.com> | 2022-01-16 08:43:42 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-01-16 13:30:28 +0100 |
| commit | 56d99e81ecbc997a5f984684d0eeb583992b2072 (patch) | |
| tree | 4284ef0b3b561af97ab5bd2dd8a6686fe86f7420 /net | |
| parent | ipv4: update fib_info_cnt under spinlock protection (diff) | |
| download | linux-56d99e81ecbc997a5f984684d0eeb583992b2072.tar.xz linux-56d99e81ecbc997a5f984684d0eeb583992b2072.zip | |
net/smc: Fix hung_task when removing SMC-R devices
A hung_task is observed when removing SMC-R devices. Suppose that
a link group has two active links(lnk_A, lnk_B) associated with two
different SMC-R devices(dev_A, dev_B). When dev_A is removed, the
link group will be removed from smc_lgr_list and added into
lgr_linkdown_list. lnk_A will be cleared and smcibdev(A)->lnk_cnt
will reach to zero. However, when dev_B is removed then, the link
group can't be found in smc_lgr_list and lnk_B won't be cleared,
making smcibdev->lnk_cnt never reaches zero, which causes a hung_task.
This patch fixes this issue by restoring the implementation of
smc_smcr_terminate_all() to what it was before commit 349d43127dac
("net/smc: fix kernel panic caused by race of smc_sock"). The original
implementation also satisfies the intention that make sure QP destroy
earlier than CQ destroy because we will always wait for smcibdev->lnk_cnt
reaches zero, which guarantees QP has been destroyed.
Fixes: 349d43127dac ("net/smc: fix kernel panic caused by race of smc_sock")
Signed-off-by: Wen Gu <guwen@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/smc/smc_core.c | 17 |
1 files changed, 1 insertions, 16 deletions
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c index 7199eeeb1667..29525d03b253 100644 --- a/net/smc/smc_core.c +++ b/net/smc/smc_core.c @@ -1531,16 +1531,11 @@ void smc_smcd_terminate_all(struct smcd_dev *smcd) /* Called when an SMCR device is removed or the smc module is unloaded. * If smcibdev is given, all SMCR link groups using this device are terminated. * If smcibdev is NULL, all SMCR link groups are terminated. - * - * We must wait here for QPs been destroyed before we destroy the CQs, - * or we won't received any CQEs and cdc_pend_tx_wr cannot reach 0 thus - * smc_sock cannot be released. */ void smc_smcr_terminate_all(struct smc_ib_device *smcibdev) { struct smc_link_group *lgr, *lg; LIST_HEAD(lgr_free_list); - LIST_HEAD(lgr_linkdown_list); int i; spin_lock_bh(&smc_lgr_list.lock); @@ -1552,7 +1547,7 @@ void smc_smcr_terminate_all(struct smc_ib_device *smcibdev) list_for_each_entry_safe(lgr, lg, &smc_lgr_list.list, list) { for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) { if (lgr->lnk[i].smcibdev == smcibdev) - list_move_tail(&lgr->list, &lgr_linkdown_list); + smcr_link_down_cond_sched(&lgr->lnk[i]); } } } @@ -1564,16 +1559,6 @@ void smc_smcr_terminate_all(struct smc_ib_device *smcibdev) __smc_lgr_terminate(lgr, false); } - list_for_each_entry_safe(lgr, lg, &lgr_linkdown_list, list) { - for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) { - if (lgr->lnk[i].smcibdev == smcibdev) { - mutex_lock(&lgr->llc_conf_mutex); - smcr_link_down_cond(&lgr->lnk[i]); - mutex_unlock(&lgr->llc_conf_mutex); - } - } - } - if (smcibdev) { if (atomic_read(&smcibdev->lnk_cnt)) wait_event(smcibdev->lnks_deleted, |