diff mbox series

[04/11] lpfc: Correct race with abort on completion path

Message ID 20180910173051.6272-5-jsmart2021@gmail.com (mailing list archive)
State Accepted
Headers show
Series lpfc updates for 12.0.0.7 | expand

Commit Message

James Smart Sept. 10, 2018, 5:30 p.m. UTC 
On io completion, the driver is taking an adapter wide lock and
nulling the scsi command back pointer.  The nulling of the back
pointer is to signify the io was completed and the scsi_done()
routine was called.  However, the routine makes no check to see
if the abort routine had done the same thing and possibly
nulled the pointer. Thus it may doubly-complete the io.

Make the following mods:
- Check to make sure forward progress (call scsi_done()) only happens
  if the command pointer was non-null.
- As the taking of the lock, which is adapter wide, is very costly
  on a system under load, null the pointer using an xchg operation
  rather than under lock.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
---
 drivers/scsi/lpfc/lpfc_scsi.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/drivers/scsi/lpfc/lpfc_scsi.c b/drivers/scsi/lpfc/lpfc_scsi.c
index 5c7858e735c9..200b5bca1f5f 100644
--- a/drivers/scsi/lpfc/lpfc_scsi.c
+++ b/drivers/scsi/lpfc/lpfc_scsi.c
@@ -4158,9 +4158,17 @@  lpfc_scsi_cmd_iocb_cmpl(struct lpfc_hba *phba, struct lpfc_iocbq *pIocbIn,
 	}
 	lpfc_scsi_unprep_dma_buf(phba, lpfc_cmd);
 
-	spin_lock_irqsave(&phba->hbalock, flags);
-	lpfc_cmd->pCmd = NULL;
-	spin_unlock_irqrestore(&phba->hbalock, flags);
+	/* If pCmd was set to NULL from abort path, do not call scsi_done */
+	if (xchg(&lpfc_cmd->pCmd, NULL) == NULL) {
+		lpfc_printf_vlog(vport, KERN_INFO, LOG_FCP,
+				 "0711 FCP cmd already NULL, sid: 0x%06x, "
+				 "did: 0x%06x, oxid: 0x%04x\n",
+				 vport->fc_myDID,
+				 (pnode) ? pnode->nlp_DID : 0,
+				 phba->sli_rev == LPFC_SLI_REV4 ?
+				 lpfc_cmd->cur_iocbq.sli4_xritag : 0xffff);
+		return;
+	}
 
 	/* The sdev is not guaranteed to be valid post scsi_done upcall. */
 	cmd->scsi_done(cmd);