[PATCH 24/25] qla2xxx: Remove extra register read

[Himanshu Madhani]

From: Quinn Tran <quinn.t...@cavium.com>

Register read is expensive in IO path, remove extra register
read in each interrupt processing to improve performance.

Signed-off-by: Quinn Tran <quinn.t...@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madh...@cavium.com>
---
 drivers/scsi/qla2xxx/qla_iocb.c   |  4 +++-
 drivers/scsi/qla2xxx/qla_target.c | 11 ++---------
 2 files changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_iocb.c b/drivers/scsi/qla2xxx/qla_iocb.c
index ea027f6a7fd4..8404f17f3c6c 100644
--- a/drivers/scsi/qla2xxx/qla_iocb.c
+++ b/drivers/scsi/qla2xxx/qla_iocb.c
@@ -464,7 +464,9 @@ qla2x00_start_iocbs(struct scsi_qla_host *vha, struct 
req_que *req)
                        req->ring_ptr++;
 
                /* Set chip new ring index. */
-               if (ha->mqenable || IS_QLA83XX(ha) || IS_QLA27XX(ha)) {
+               if (ha->mqenable || IS_QLA27XX(ha)) {
+                       WRT_REG_DWORD(req->req_q_in, req->ring_index);
+               } else if (IS_QLA83XX(ha)) {
                        WRT_REG_DWORD(req->req_q_in, req->ring_index);
                        RD_REG_DWORD_RELAXED(&ha->iobase->isp24.hccr);
                } else if (IS_QLAFX00(ha)) {
diff --git a/drivers/scsi/qla2xxx/qla_target.c 
b/drivers/scsi/qla2xxx/qla_target.c
index 95aad9c329d7..f42313e49443 100644
--- a/drivers/scsi/qla2xxx/qla_target.c
+++ b/drivers/scsi/qla2xxx/qla_target.c
@@ -2223,11 +2223,10 @@ static void qlt_unmap_sg(struct scsi_qla_host *vha, 
struct qla_tgt_cmd *cmd)
 static int qlt_check_reserve_free_req(struct scsi_qla_host *vha,
        uint32_t req_cnt)
 {
-       uint32_t cnt, cnt_in;
+       uint32_t cnt;
 
        if (vha->req->cnt < (req_cnt + 2)) {
                cnt = (uint16_t)RD_REG_DWORD(vha->req->req_q_out);
-               cnt_in = (uint16_t)RD_REG_DWORD(vha->req->req_q_in);
 
                if  (vha->req->ring_index < cnt)
                        vha->req->cnt = cnt - vha->req->ring_index;
@@ -2235,14 +2234,8 @@ static int qlt_check_reserve_free_req(struct 
scsi_qla_host *vha,
                        vha->req->cnt = vha->req->length -
                            (vha->req->ring_index - cnt);
 
-               if (unlikely(vha->req->cnt < (req_cnt + 2))) {
-                       ql_dbg(ql_dbg_io, vha, 0x305a,
-                           "qla_target(%d): There is no room in the request 
ring: vha->req->ring_index=%d, vha->req->cnt=%d, req_cnt=%d Req-out=%d 
Req-in=%d Req-Length=%d\n",
-                           vha->vp_idx, vha->req->ring_index,
-                           vha->req->cnt, req_cnt, cnt, cnt_in,
-                           vha->req->length);
+               if (unlikely(vha->req->cnt < (req_cnt + 2)))
                        return -EAGAIN;
-               }
        }
 
        vha->req->cnt -= req_cnt;
-- 
2.12.0