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scsi: qla2xxx: deadlock by configfs_depend_item 

The intent of invoking configfs_depend_item in commit 7474f52a82
("tcm_qla2xxx: Perform configfs depend/undepend for base_tpg")
was to prevent a physical Fibre Channel port removal when
virtual (NPIV) ports announced through that physical port are active.
The change does not work as expected: it makes enabled physical port
dependent on target configfs subsystem (the port's parent), something
the configfs guarantees anyway.

Besides, scheduling work in a worker thread and waiting for the work's
completion is not really a valid workaround for the requirement not to call
configfs_depend_item from a configfs callback: the call occasionally
deadlocks.

Thus, removing configfs_depend_item calls does not break anything and fixes
the deadlock problem.

Signed-off-by: Anatoliy Glagolev <glagolig@gmail.com>
Acked-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
5.0.x+fslc
Anatoliy Glagolev 2018-12-06 16:48:45 -07:00 committed by Martin K. Petersen
parent 38417468d4
commit 17b18eaa6f
2 changed files with 8 additions and 43 deletions
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48
drivers/scsi/qla2xxx/tcm_qla2xxx.c
View File

@ -954,38 +954,14 @@ static ssize_t tcm_qla2xxx_tpg_enable_show(struct config_item *item,
atomic_read(&tpg->lport_tpg_enabled));
}
static void tcm_qla2xxx_depend_tpg(struct work_struct *work)
{
struct tcm_qla2xxx_tpg *base_tpg = container_of(work,
struct tcm_qla2xxx_tpg, tpg_base_work);
struct se_portal_group *se_tpg = &base_tpg->se_tpg;
struct scsi_qla_host *base_vha = base_tpg->lport->qla_vha;
if (!target_depend_item(&se_tpg->tpg_group.cg_item)) {
atomic_set(&base_tpg->lport_tpg_enabled, 1);
qlt_enable_vha(base_vha);
}
complete(&base_tpg->tpg_base_comp);
}
static void tcm_qla2xxx_undepend_tpg(struct work_struct *work)
{
struct tcm_qla2xxx_tpg *base_tpg = container_of(work,
struct tcm_qla2xxx_tpg, tpg_base_work);
struct se_portal_group *se_tpg = &base_tpg->se_tpg;
struct scsi_qla_host *base_vha = base_tpg->lport->qla_vha;
if (!qlt_stop_phase1(base_vha->vha_tgt.qla_tgt)) {
atomic_set(&base_tpg->lport_tpg_enabled, 0);
target_undepend_item(&se_tpg->tpg_group.cg_item);
}
complete(&base_tpg->tpg_base_comp);
}
static ssize_t tcm_qla2xxx_tpg_enable_store(struct config_item *item,
const char *page, size_t count)
{
struct se_portal_group *se_tpg = to_tpg(item);
struct se_wwn *se_wwn = se_tpg->se_tpg_wwn;
struct tcm_qla2xxx_lport *lport = container_of(se_wwn,
struct tcm_qla2xxx_lport, lport_wwn);
struct scsi_qla_host *vha = lport->qla_vha;
struct tcm_qla2xxx_tpg *tpg = container_of(se_tpg,
struct tcm_qla2xxx_tpg, se_tpg);
unsigned long op;
@ -1004,24 +980,16 @@ static ssize_t tcm_qla2xxx_tpg_enable_store(struct config_item *item,
if (atomic_read(&tpg->lport_tpg_enabled))
return -EEXIST;
INIT_WORK(&tpg->tpg_base_work, tcm_qla2xxx_depend_tpg);
atomic_set(&tpg->lport_tpg_enabled, 1);
qlt_enable_vha(vha);
} else {
if (!atomic_read(&tpg->lport_tpg_enabled))
return count;
INIT_WORK(&tpg->tpg_base_work, tcm_qla2xxx_undepend_tpg);
atomic_set(&tpg->lport_tpg_enabled, 0);
qlt_stop_phase1(vha->vha_tgt.qla_tgt);
}
init_completion(&tpg->tpg_base_comp);
schedule_work(&tpg->tpg_base_work);
wait_for_completion(&tpg->tpg_base_comp);
if (op) {
if (!atomic_read(&tpg->lport_tpg_enabled))
return -ENODEV;
} else {
if (atomic_read(&tpg->lport_tpg_enabled))
return -EPERM;
}
return count;
}

3
drivers/scsi/qla2xxx/tcm_qla2xxx.h
View File

@ -48,9 +48,6 @@ struct tcm_qla2xxx_tpg {
struct tcm_qla2xxx_tpg_attrib tpg_attrib;
/* Returned by tcm_qla2xxx_make_tpg() */
struct se_portal_group se_tpg;
/* Items for dealing with configfs_depend_item */
struct completion tpg_base_comp;
struct work_struct tpg_base_work;
};
struct tcm_qla2xxx_fc_loopid {