| From e8a8f5b00c8d0ca0d5b35277b8e0fc840acc5357 Mon Sep 17 00:00:00 2001 |
| From: James Smart <jsmart2021@gmail.com> |
| Date: Tue, 12 Mar 2019 16:30:05 -0700 |
| Subject: scsi: lpfc: Resolve irq-unsafe lockdep heirarchy warning in |
| lpfc_io_free |
| |
| [ Upstream commit 50e3f871fb20a9bb644743e2986e8f50f98a25bc ] |
| |
| A patch in the 12.2.0.0 set caused a new lockdep warning: |
| |
| WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected |
| 5.0.0-rc8-next-20190301-dbg+ #1 Not tainted |
| |
| Possible interrupt unsafe locking scenario: |
| CPU0 CPU1 |
| ---- ---- |
| lock(&(&qp->io_buf_list_put_lock)->rlock); |
| local_irq_disable(); |
| lock(&(&phba->hbalock)->rlock); |
| lock(&(&qp->io_buf_list_put_lock)->rlock); |
| <Interrupt> |
| lock(&(&phba->hbalock)->rlock); |
| |
| see: https://www.spinics.net/lists/linux-scsi/msg128389.html |
| |
| In summary, the new patch added taking the io_buf_list_put_lock while under |
| an irq-disabled hbalock. This created a lock heirarchy dependent upon irq |
| being disabled, and there are paths that take the io_buf_list_put_lock |
| without disabling irq. |
| |
| Looking at the lpfc_io_free routine, which is where the new heirarchy was |
| introduced, there is no reason to be taking out the hbalock and raising |
| irq, as the functionality is replaced by the io_buf_list_xxx locks. |
| |
| Resolve by removing the hbalock/irq calls in lpfc_io_free. |
| |
| Fixes: 5e5b511d8bfa ("scsi: lpfc: Partition XRI buffer list across Hardware Queues") |
| Reported-by: Bart Van Assche <bvanassche@acm.org> |
| Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com> |
| Signed-off-by: James Smart <jsmart2021@gmail.com> |
| Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/scsi/lpfc/lpfc_init.c | 4 ---- |
| 1 file changed, 4 deletions(-) |
| |
| diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c |
| index 89a0c2bdb6a15..46e155d1fa155 100644 |
| --- a/drivers/scsi/lpfc/lpfc_init.c |
| +++ b/drivers/scsi/lpfc/lpfc_init.c |
| @@ -3618,8 +3618,6 @@ lpfc_io_free(struct lpfc_hba *phba) |
| struct lpfc_sli4_hdw_queue *qp; |
| int idx; |
| |
| - spin_lock_irq(&phba->hbalock); |
| - |
| for (idx = 0; idx < phba->cfg_hdw_queue; idx++) { |
| qp = &phba->sli4_hba.hdwq[idx]; |
| /* Release all the lpfc_nvme_bufs maintained by this host. */ |
| @@ -3649,8 +3647,6 @@ lpfc_io_free(struct lpfc_hba *phba) |
| } |
| spin_unlock(&qp->io_buf_list_get_lock); |
| } |
| - |
| - spin_unlock_irq(&phba->hbalock); |
| } |
| |
| /** |
| -- |
| 2.20.1 |
| |
