linux-kernel - [PATCH v3] rtw88: pci: Move a mass of jobs in hw IRQ to soft IRQ

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Message-Id: <20190820045934.24841-1-jian-hong@endlessm.com>
Date:   Tue, 20 Aug 2019 12:59:35 +0800
From:   Jian-Hong Pan <jian-hong@...lessm.com>
To:     Yan-Hsuan Chuang <yhchuang@...ltek.com>,
        Kalle Valo <kvalo@...eaurora.org>,
        "David S . Miller" <davem@...emloft.net>
Cc:     linux-wireless@...r.kernel.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux@...lessm.com,
        Jian-Hong Pan <jian-hong@...lessm.com>
Subject: [PATCH v3] rtw88: pci: Move a mass of jobs in hw IRQ to soft IRQ

There is a mass of jobs between spin lock and unlock in the hardware
IRQ which will occupy much time originally. To make system work more
efficiently, this patch moves the jobs to the soft IRQ (bottom half) to
reduce the time in hardware IRQ.

Signed-off-by: Jian-Hong Pan <jian-hong@...lessm.com>
---
v2:
 Change the spin_lock_irqsave/unlock_irqrestore to spin_lock/unlock in
 rtw_pci_interrupt_handler. Because the interrupts are already disabled
 in the hardware interrupt handler.

v3:
 Extend the spin lock protecting area for the TX path in
 rtw_pci_interrupt_threadfn by Realtek's suggestion

 drivers/net/wireless/realtek/rtw88/pci.c | 33 +++++++++++++++++++-----
 1 file changed, 27 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtw88/pci.c b/drivers/net/wireless/realtek/rtw88/pci.c
index 00ef229552d5..a8c17a01f318 100644
--- a/drivers/net/wireless/realtek/rtw88/pci.c
+++ b/drivers/net/wireless/realtek/rtw88/pci.c
@@ -866,12 +866,29 @@ static irqreturn_t rtw_pci_interrupt_handler(int irq, void *dev)
 {
 	struct rtw_dev *rtwdev = dev;
 	struct rtw_pci *rtwpci = (struct rtw_pci *)rtwdev->priv;
-	u32 irq_status[4];
 
 	spin_lock(&rtwpci->irq_lock);
 	if (!rtwpci->irq_enabled)
 		goto out;
 
+	/* disable RTW PCI interrupt to avoid more interrupts before the end of
+	 * thread function
+	 */
+	rtw_pci_disable_interrupt(rtwdev, rtwpci);
+out:
+	spin_unlock(&rtwpci->irq_lock);
+
+	return IRQ_WAKE_THREAD;
+}
+
+static irqreturn_t rtw_pci_interrupt_threadfn(int irq, void *dev)
+{
+	struct rtw_dev *rtwdev = dev;
+	struct rtw_pci *rtwpci = (struct rtw_pci *)rtwdev->priv;
+	unsigned long flags;
+	u32 irq_status[4];
+
+	spin_lock_irqsave(&rtwpci->irq_lock, flags);
 	rtw_pci_irq_recognized(rtwdev, rtwpci, irq_status);
 
 	if (irq_status[0] & IMR_MGNTDOK)
@@ -891,8 +908,10 @@ static irqreturn_t rtw_pci_interrupt_handler(int irq, void *dev)
 	if (irq_status[0] & IMR_ROK)
 		rtw_pci_rx_isr(rtwdev, rtwpci, RTW_RX_QUEUE_MPDU);
 
-out:
-	spin_unlock(&rtwpci->irq_lock);
+	/* all of the jobs for this interrupt have been done */
+	if (rtw_flag_check(rtwdev, RTW_FLAG_RUNNING))
+		rtw_pci_enable_interrupt(rtwdev, rtwpci);
+	spin_unlock_irqrestore(&rtwpci->irq_lock, flags);
 
 	return IRQ_HANDLED;
 }
@@ -1152,8 +1171,10 @@ static int rtw_pci_probe(struct pci_dev *pdev,
 		goto err_destroy_pci;
 	}
 
-	ret = request_irq(pdev->irq, &rtw_pci_interrupt_handler,
-			  IRQF_SHARED, KBUILD_MODNAME, rtwdev);
+	ret = devm_request_threaded_irq(rtwdev->dev, pdev->irq,
+					rtw_pci_interrupt_handler,
+					rtw_pci_interrupt_threadfn,
+					IRQF_SHARED, KBUILD_MODNAME, rtwdev);
 	if (ret) {
 		ieee80211_unregister_hw(hw);
 		goto err_destroy_pci;
@@ -1192,7 +1213,7 @@ static void rtw_pci_remove(struct pci_dev *pdev)
 	rtw_pci_disable_interrupt(rtwdev, rtwpci);
 	rtw_pci_destroy(rtwdev, pdev);
 	rtw_pci_declaim(rtwdev, pdev);
-	free_irq(rtwpci->pdev->irq, rtwdev);
+	devm_free_irq(rtwdev->dev, rtwpci->pdev->irq, rtwdev);
 	rtw_core_deinit(rtwdev);
 	ieee80211_free_hw(hw);
 }
-- 
2.20.1