scsi: hisi_sas: save completion queue read pointer

Optimise by saving an avoidable read in the cq interrupt.  The queue
read pointer will only be updated by software, so don't bother
re-reading what was already written in the previous interrupt.

Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/hisi_sas/hisi_sas.h b/drivers/scsi/hisi_sas/hisi_sas.h
index ca55ec2974e0902a46ab5fca922086975fa2794e..9410335caf41a5506ace830bbd356751f08d0928 100644 (file)
--- a/drivers/scsi/hisi_sas/hisi_sas.h
+++ b/drivers/scsi/hisi_sas/hisi_sas.h
@@ -94,6 +94,7 @@ struct hisi_sas_port {
 
 struct hisi_sas_cq {
        struct hisi_hba *hisi_hba;
+       int     rd_point;
        int     id;
 };
 

diff --git a/drivers/scsi/hisi_sas/hisi_sas_v1_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v1_hw.c
index 1abbc2e162dfd313422cefbec039dca99b630736..3b31b204655960ff0b3fc5883c599ca29b560354 100644 (file)
--- a/drivers/scsi/hisi_sas/hisi_sas_v1_hw.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_v1_hw.c
@@ -1565,14 +1565,11 @@ static irqreturn_t cq_interrupt_v1_hw(int irq, void *p)
        struct hisi_sas_complete_v1_hdr *complete_queue =
                        (struct hisi_sas_complete_v1_hdr *)
                        hisi_hba->complete_hdr[queue];
-       u32 irq_value, rd_point, wr_point;
+       u32 irq_value, rd_point = cq->rd_point, wr_point;
 
        irq_value = hisi_sas_read32(hisi_hba, OQ_INT_SRC);
 
        hisi_sas_write32(hisi_hba, OQ_INT_SRC, 1 << queue);
-
-       rd_point = hisi_sas_read32(hisi_hba,
-                       COMPL_Q_0_RD_PTR + (0x14 * queue));
        wr_point = hisi_sas_read32(hisi_hba,
                        COMPL_Q_0_WR_PTR + (0x14 * queue));
 
@@ -1600,6 +1597,7 @@ static irqreturn_t cq_interrupt_v1_hw(int irq, void *p)
        }
 
        /* update rd_point */
+       cq->rd_point = rd_point;
        hisi_sas_write32(hisi_hba, COMPL_Q_0_RD_PTR + (0x14 * queue), rd_point);
 
        return IRQ_HANDLED;

diff --git a/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c
index bf9b693a717fb46578c9a680bf5cb1450843c732..11006c99de540b3dae5ef4ffee789ff975ddd1c0 100644 (file)
--- a/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c
@@ -2049,7 +2049,7 @@ static irqreturn_t cq_interrupt_v2_hw(int irq_no, void *p)
        struct hisi_sas_slot *slot;
        struct hisi_sas_itct *itct;
        struct hisi_sas_complete_v2_hdr *complete_queue;
-       u32 irq_value, rd_point, wr_point, dev_id;
+       u32 irq_value, rd_point = cq->rd_point, wr_point, dev_id;
        int queue = cq->id;
 
        complete_queue = hisi_hba->complete_hdr[queue];
@@ -2057,8 +2057,6 @@ static irqreturn_t cq_interrupt_v2_hw(int irq_no, void *p)
 
        hisi_sas_write32(hisi_hba, OQ_INT_SRC, 1 << queue);
 
-       rd_point = hisi_sas_read32(hisi_hba, COMPL_Q_0_RD_PTR +
-                                  (0x14 * queue));
        wr_point = hisi_sas_read32(hisi_hba, COMPL_Q_0_WR_PTR +
                                   (0x14 * queue));
 
@@ -2106,6 +2104,7 @@ static irqreturn_t cq_interrupt_v2_hw(int irq_no, void *p)
        }
 
        /* update rd_point */
+       cq->rd_point = rd_point;
        hisi_sas_write32(hisi_hba, COMPL_Q_0_RD_PTR + (0x14 * queue), rd_point);
        return IRQ_HANDLED;
 }