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From: John Garry <john.garry@huawei.com>
To: <jejb@linux.vnet.ibm.com>, <martin.petersen@oracle.com>
Cc: <linux-scsi@vger.kernel.org>, <linuxarm@huawei.com>,
	<linux-kernel@vger.kernel.org>,
	Xiang Chen <chenxiang66@hisilicon.com>,
	"John Garry" <john.garry@huawei.com>
Subject: [PATCH 01/11] scsi: hisi_sas: optimise the usage of DQ locking
Date: Wed, 2 May 2018 23:56:24 +0800	[thread overview]
Message-ID: <1525276594-92173-2-git-send-email-john.garry@huawei.com> (raw)
In-Reply-To: <1525276594-92173-1-git-send-email-john.garry@huawei.com>

From: Xiang Chen <chenxiang66@hisilicon.com>

In the DQ tasklet processing it is not necessary to take the DQ
lock, as there is no contention between adding slots to the CQ and
removing slots from the matching DQ.

In addition, since we run each DQ in a separate tasklet context,
there would be no possible contention between DQ processing
running for the same queue in parallel.

It is still necessary to take hisi_hba lock when free'ing slots.

Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: John Garry <john.garry@huawei.com>
---
 drivers/scsi/hisi_sas/hisi_sas_v2_hw.c | 3 ---
 drivers/scsi/hisi_sas/hisi_sas_v3_hw.c | 3 ---
 2 files changed, 6 deletions(-)

diff --git a/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c
index a5abde8..384e4ef 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_v2_hw.c
@@ -3151,14 +3151,12 @@ static void cq_tasklet_v2_hw(unsigned long val)
 	struct hisi_sas_complete_v2_hdr *complete_queue;
 	u32 rd_point = cq->rd_point, wr_point, dev_id;
 	int queue = cq->id;
-	struct hisi_sas_dq *dq = &hisi_hba->dq[queue];
 
 	if (unlikely(hisi_hba->reject_stp_links_msk))
 		phys_try_accept_stp_links_v2_hw(hisi_hba);
 
 	complete_queue = hisi_hba->complete_hdr[queue];
 
-	spin_lock(&dq->lock);
 	wr_point = hisi_sas_read32(hisi_hba, COMPL_Q_0_WR_PTR +
 				   (0x14 * queue));
 
@@ -3208,7 +3206,6 @@ static void cq_tasklet_v2_hw(unsigned long val)
 	/* update rd_point */
 	cq->rd_point = rd_point;
 	hisi_sas_write32(hisi_hba, COMPL_Q_0_RD_PTR + (0x14 * queue), rd_point);
-	spin_unlock(&dq->lock);
 }
 
 static irqreturn_t cq_interrupt_v2_hw(int irq_no, void *p)
diff --git a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
index 33735a7..afc1242 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
@@ -1721,11 +1721,9 @@ static void cq_tasklet_v3_hw(unsigned long val)
 	struct hisi_sas_complete_v3_hdr *complete_queue;
 	u32 rd_point = cq->rd_point, wr_point;
 	int queue = cq->id;
-	struct hisi_sas_dq *dq = &hisi_hba->dq[queue];
 
 	complete_queue = hisi_hba->complete_hdr[queue];
 
-	spin_lock(&dq->lock);
 	wr_point = hisi_sas_read32(hisi_hba, COMPL_Q_0_WR_PTR +
 				   (0x14 * queue));
 
@@ -1752,7 +1750,6 @@ static void cq_tasklet_v3_hw(unsigned long val)
 	/* update rd_point */
 	cq->rd_point = rd_point;
 	hisi_sas_write32(hisi_hba, COMPL_Q_0_RD_PTR + (0x14 * queue), rd_point);
-	spin_unlock(&dq->lock);
 }
 
 static irqreturn_t cq_interrupt_v3_hw(int irq_no, void *p)
-- 
1.9.1

  reply	other threads:[~2018-05-02 15:57 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-02 15:56 [PATCH 00/11] hisi_sas: some misc patches John Garry
2018-05-02 15:56 ` John Garry [this message]
2018-05-02 15:56 ` [PATCH 02/11] scsi: hisi_sas: Add some checks to avoid free'ing a sas_task twice John Garry
2018-05-02 15:56 ` [PATCH 03/11] scsi: hisi_sas: check host frozen before calling "done" function John Garry
2018-05-02 15:56 ` [PATCH 04/11] scsi: hisi_sas: fix PI memory size John Garry
2018-05-02 15:56 ` [PATCH 05/11] scsi: hisi_sas: check sas_dev gone earlier in hisi_sas_abort_task() John Garry
2018-05-02 15:56 ` [PATCH 06/11] scsi: hisi_sas: stop controller timer for reset John Garry
2018-05-02 15:56 ` [PATCH 07/11] scsi: hisi_sas: update PHY linkrate after a controller reset John Garry
2018-05-02 15:56 ` [PATCH 08/11] scsi: hisi_sas: config ATA de-reset as an constrained command for v3 hw John Garry
2018-05-02 15:56 ` [PATCH 09/11] scsi: hisi_sas: remove redundant handling to event95 for v3 John Garry
2018-05-02 15:56 ` [PATCH 10/11] scsi: hisi_sas: add readl poll timeout helper wrappers John Garry
2018-05-02 15:56 ` [PATCH 11/11] scsi: hisi_sas: workaround a v3 hw hilink bug John Garry
2018-05-08  5:16 ` [PATCH 00/11] hisi_sas: some misc patches Martin K. Petersen

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