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Commit 894bb17f authored by James Smart's avatar James Smart Committed by Martin K. Petersen
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scsi: lpfc: Fix deadlock on host_lock during cable pulls 



During cable pull testing a deadlock was seen between lpfc_nlp_counters()
vs lpfc_mbox_process_link_up() vs lpfc_work_list_done(). They are all
waiting on the shost->host_lock.

Issue is all of these cases raise irq when taking out the lock but use
spin_unlock_irq() when unlocking. The unlock path is will unconditionally
re-enable interrupts in cases where irq state should be preserved. The
re-enablement allowed the other paths to execute which then causes the
deadlock.

Fix by converting the lock/unlock to irqsave/irqrestore.

Signed-off-by: default avatarDick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: default avatarJames Smart <jsmart2021@gmail.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 6825b7bd

drivers/scsi/lpfc/lpfc_hbadisc.c

+26 −21
Original line number Diff line number Diff line
@@ -118,6 +118,7 @@ lpfc_dev_loss_tmo_callbk(struct fc_rport *rport) 
	struct lpfc_work_evt *evtp;

	int  put_node;

	int  put_rport;

	unsigned long iflags;



	rdata = rport->dd_data;

	ndlp = rdata->pnode;
@@ -170,22 +171,22 @@ lpfc_dev_loss_tmo_callbk(struct fc_rport *rport) 
	}



	shost = lpfc_shost_from_vport(vport);

	spin_lock_irq(shost->host_lock);

	spin_lock_irqsave(shost->host_lock, iflags);

	ndlp->nlp_flag |= NLP_IN_DEV_LOSS;

	spin_unlock_irq(shost->host_lock);

	spin_unlock_irqrestore(shost->host_lock, iflags);



	/* We need to hold the node by incrementing the reference

	 * count until this queued work is done

	 */

	evtp->evt_arg1  = lpfc_nlp_get(ndlp);



	spin_lock_irq(&phba->hbalock);

	spin_lock_irqsave(&phba->hbalock, iflags);

	if (evtp->evt_arg1) {

		evtp->evt = LPFC_EVT_DEV_LOSS;

		list_add_tail(&evtp->evt_listp, &phba->work_list);

		lpfc_worker_wake_up(phba);

	}

	spin_unlock_irq(&phba->hbalock);

	spin_unlock_irqrestore(&phba->hbalock, iflags);



	return;

}
@@ -212,14 +213,15 @@ lpfc_dev_loss_tmo_handler(struct lpfc_nodelist *ndlp) 
	int  put_node;

	int warn_on = 0;

	int fcf_inuse = 0;

	unsigned long iflags;



	rport = ndlp->rport;

	vport = ndlp->vport;

	shost = lpfc_shost_from_vport(vport);



	spin_lock_irq(shost->host_lock);

	spin_lock_irqsave(shost->host_lock, iflags);

	ndlp->nlp_flag &= ~NLP_IN_DEV_LOSS;

	spin_unlock_irq(shost->host_lock);

	spin_unlock_irqrestore(shost->host_lock, iflags);



	if (!rport)

		return fcf_inuse;
@@ -3115,8 +3117,9 @@ lpfc_mbx_process_link_up(struct lpfc_hba *phba, struct lpfc_mbx_read_top *la) 
	int rc;

	struct fcf_record *fcf_record;

	uint32_t fc_flags = 0;

	unsigned long iflags;



	spin_lock_irq(&phba->hbalock);

	spin_lock_irqsave(&phba->hbalock, iflags);

	phba->fc_linkspeed = bf_get(lpfc_mbx_read_top_link_spd, la);



	if (!(phba->hba_flag & HBA_FCOE_MODE)) {
@@ -3213,12 +3216,12 @@ lpfc_mbx_process_link_up(struct lpfc_hba *phba, struct lpfc_mbx_read_top *la) 
		vport->fc_myDID = phba->fc_pref_DID;

		fc_flags |= FC_LBIT;

	}

	spin_unlock_irq(&phba->hbalock);

	spin_unlock_irqrestore(&phba->hbalock, iflags);



	if (fc_flags) {

		spin_lock_irq(shost->host_lock);

		spin_lock_irqsave(shost->host_lock, iflags);

		vport->fc_flag |= fc_flags;

		spin_unlock_irq(shost->host_lock);

		spin_unlock_irqrestore(shost->host_lock, iflags);

	}



	lpfc_linkup(phba);
@@ -3292,22 +3295,22 @@ lpfc_mbx_process_link_up(struct lpfc_hba *phba, struct lpfc_mbx_read_top *la) 
		 * The driver is expected to do FIP/FCF. Call the port

		 * and get the FCF Table.

		 */

		spin_lock_irq(&phba->hbalock);

		spin_lock_irqsave(&phba->hbalock, iflags);

		if (phba->hba_flag & FCF_TS_INPROG) {

			spin_unlock_irq(&phba->hbalock);

			spin_unlock_irqrestore(&phba->hbalock, iflags);

			return;

		}

		/* This is the initial FCF discovery scan */

		phba->fcf.fcf_flag |= FCF_INIT_DISC;

		spin_unlock_irq(&phba->hbalock);

		spin_unlock_irqrestore(&phba->hbalock, iflags);

		lpfc_printf_log(phba, KERN_INFO, LOG_FIP | LOG_DISCOVERY,

				"2778 Start FCF table scan at linkup\n");

		rc = lpfc_sli4_fcf_scan_read_fcf_rec(phba,

						     LPFC_FCOE_FCF_GET_FIRST);

		if (rc) {

			spin_lock_irq(&phba->hbalock);

			spin_lock_irqsave(&phba->hbalock, iflags);

			phba->fcf.fcf_flag &= ~FCF_INIT_DISC;

			spin_unlock_irq(&phba->hbalock);

			spin_unlock_irqrestore(&phba->hbalock, iflags);

			goto out;

		}

		/* Reset FCF roundrobin bmask for new discovery */
@@ -3366,6 +3369,7 @@ lpfc_mbx_cmpl_read_topology(struct lpfc_hba *phba, LPFC_MBOXQ_t *pmb) 
	MAILBOX_t *mb = &pmb->u.mb;

	struct lpfc_dmabuf *mp = (struct lpfc_dmabuf *)(pmb->ctx_buf);

	uint8_t attn_type;

	unsigned long iflags;



	/* Unblock ELS traffic */

	pring = lpfc_phba_elsring(phba);
@@ -3387,12 +3391,12 @@ lpfc_mbx_cmpl_read_topology(struct lpfc_hba *phba, LPFC_MBOXQ_t *pmb) 


	memcpy(&phba->alpa_map[0], mp->virt, 128);



	spin_lock_irq(shost->host_lock);

	spin_lock_irqsave(shost->host_lock, iflags);

	if (bf_get(lpfc_mbx_read_top_pb, la))

		vport->fc_flag |= FC_BYPASSED_MODE;

	else

		vport->fc_flag &= ~FC_BYPASSED_MODE;

	spin_unlock_irq(shost->host_lock);

	spin_unlock_irqrestore(shost->host_lock, iflags);



	if (phba->fc_eventTag <= la->eventTag) {

		phba->fc_stat.LinkMultiEvent++;
@@ -3403,12 +3407,12 @@ lpfc_mbx_cmpl_read_topology(struct lpfc_hba *phba, LPFC_MBOXQ_t *pmb) 


	phba->fc_eventTag = la->eventTag;

	if (phba->sli_rev < LPFC_SLI_REV4) {

		spin_lock_irq(&phba->hbalock);

		spin_lock_irqsave(&phba->hbalock, iflags);

		if (bf_get(lpfc_mbx_read_top_mm, la))

			phba->sli.sli_flag |= LPFC_MENLO_MAINT;

		else

			phba->sli.sli_flag &= ~LPFC_MENLO_MAINT;

		spin_unlock_irq(&phba->hbalock);

		spin_unlock_irqrestore(&phba->hbalock, iflags);

	}



	phba->link_events++;
@@ -4196,8 +4200,9 @@ static void 
lpfc_nlp_counters(struct lpfc_vport *vport, int state, int count)

{

	struct Scsi_Host *shost = lpfc_shost_from_vport(vport);

	unsigned long iflags;



	spin_lock_irq(shost->host_lock);

	spin_lock_irqsave(shost->host_lock, iflags);

	switch (state) {

	case NLP_STE_UNUSED_NODE:

		vport->fc_unused_cnt += count;
@@ -4227,7 +4232,7 @@ lpfc_nlp_counters(struct lpfc_vport *vport, int state, int count) 
			vport->fc_npr_cnt += count;

		break;

	}

	spin_unlock_irq(shost->host_lock);

	spin_unlock_irqrestore(shost->host_lock, iflags);

}



static void