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Commit f2970af1 authored by Anatoliy Glagolev's avatar Anatoliy Glagolev Committed by Greg Kroah-Hartman
Browse files

scsi: qla2xxx: deadlock by configfs_depend_item 



[ Upstream commit 17b18eaa6f59044a5172db7d07149e31ede0f920 ]

The intent of invoking configfs_depend_item in commit 7474f52a
("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: default avatarAnatoliy Glagolev <glagolig@gmail.com>
Acked-by: default avatarHimanshu Madhani <hmadhani@marvell.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent c041756d

drivers/scsi/qla2xxx/tcm_qla2xxx.c

+8 −40
Original line number Diff line number Diff line
@@ -821,38 +821,14 @@ 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;
@@ -871,24 +847,16 @@ 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;

}

drivers/scsi/qla2xxx/tcm_qla2xxx.h

+0 −3
Original line number Diff line number Diff line
@@ -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 {