scsi: lpfc: Fix RQ buffer leakage when no IOCBs available

BugLink: https://bugs.launchpad.net/bugs/1855303
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@gmail.com
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>
(cherry picked from commit 39c4f1a965a9244c3ba60695e8ff8da065ec6ac4 linux-next)
Signed-off-by: Jeff Lane <jeffrey.lane@canonical.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>

diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c
index e660ee98ad8b17a13cc67fcb2089fe5b651e3591..0d9be7556574a42a76690d9105eae61466dbd49e 100644 (file)
--- a/drivers/scsi/lpfc/lpfc_sli.c
+++ b/drivers/scsi/lpfc/lpfc_sli.c
@@ -17950,6 +17950,10 @@ 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;
 }