[PATCH AUTOSEL 4.9 36/90] scsi: lpfc: Fix RQ buffer leakage when no IOCBs available

[Sasha Levin]

From: James Smart <jsmart2021@xxxxxxxxx>

[ Upstream commit 39c4f1a965a9244c3ba60695e8ff8da065ec6ac4 ]

The driver is occasionally seeing the following SLI Port error, requiring
reset and reinit:

 Port Status Event: ... error 1=0x52004a01, error 2=0x218

The failure means an RQ timeout. That is, the adapter had received
asynchronous receive frames, ran out of buffer slots to place the frames,
and the driver did not replenish the buffer slots before a timeout
occurred. The driver should not be so slow in replenishing buffers that a
timeout can occur.

When the driver received all the frames of a sequence, it allocates an IOCB
to put the frames in. In a situation where there was no IOCB available for
the frame of a sequence, the RQ buffer corresponding to the first frame of
the sequence was not returned to the FW. Eventually, with enough traffic
encountering the situation, the timeout occurred.

Fix by releasing the buffer back to firmware whenever there is no IOCB for
the first frame.

[mkp: typo]

Link: https://lore.kernel.org/r/20200128002312.16346-2-jsmart2021@xxxxxxxxx
Signed-off-by: Dick Kennedy <dick.kennedy@xxxxxxxxxxxx>
Signed-off-by: James Smart <jsmart2021@xxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/scsi/lpfc/lpfc_sli.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c
index 1c34dc3355498..08c76c361e8dc 100644
--- a/drivers/scsi/lpfc/lpfc_sli.c
+++ b/drivers/scsi/lpfc/lpfc_sli.c
@@ -15648,6 +15648,10 @@ lpfc_prep_seq(struct lpfc_vport *vport, struct hbq_dmabuf *seq_dmabuf)
 			list_add_tail(&iocbq->list, &first_iocbq->list);
 		}
 	}
+	/* Free the sequence's header buffer */
+	if (!first_iocbq)
+		lpfc_in_buf_free(vport->phba, &seq_dmabuf->dbuf);
+
 	return first_iocbq;
 }
 
-- 
2.25.1