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From: Dexuan Cui <decui@microsoft.com>
To: "lorenzo.pieralisi@arm.com" <lorenzo.pieralisi@arm.com>,
	"bhelgaas@google.com" <bhelgaas@google.com>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	KY Srinivasan <kys@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>
Cc: "olaf@aepfle.de" <olaf@aepfle.de>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	"driverdev-devel@linuxdriverproject.org"
	<driverdev-devel@linuxdriverproject.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Michael Kelley \(EOSG\)" <Michael.H.Kelley@microsoft.com>,
	"marcelo.cerri@canonical.com" <marcelo.cerri@canonical.com>,
	"apw@canonical.com" <apw@canonical.com>,
	"vkuznets@redhat.com" <vkuznets@redhat.com>,
	"jasowang@redhat.com" <jasowang@redhat.com>
Subject: [PATCH v4 4/4] PCI: hv: Only queue a new work in hv_pci_devices_present() if necessary
Date: Thu, 15 Mar 2018 14:22:00 +0000	[thread overview]
Message-ID: <KL1P15301MB0006CFED2B13C56CDDD2A153BFD00@KL1P15301MB0006.APCP153.PROD.OUTLOOK.COM> (raw)

If there is a pending work, we just need to add the new dr into
the dr_list.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Acked-by: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Jack Morgenstein <jackm@mellanox.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
---
 drivers/pci/host/pci-hyperv.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
index 0dc2ecdbbe45..50cdefe3f6d3 100644
--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -1789,6 +1789,7 @@ static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
 	struct hv_dr_state *dr;
 	struct hv_dr_work *dr_wrk;
 	unsigned long flags;
+	bool pending_dr;
 
 	dr_wrk = kzalloc(sizeof(*dr_wrk), GFP_NOWAIT);
 	if (!dr_wrk)
@@ -1812,11 +1813,21 @@ static void hv_pci_devices_present(struct hv_pcibus_device *hbus,
 	}
 
 	spin_lock_irqsave(&hbus->device_list_lock, flags);
+	/*
+	 * If pending_dr is true, we have already queued a work,
+	 * which will see the new dr. Otherwise, we need to
+	 * queue a new work.
+	 */
+	pending_dr = !list_empty(&hbus->dr_list);
 	list_add_tail(&dr->list_entry, &hbus->dr_list);
 	spin_unlock_irqrestore(&hbus->device_list_lock, flags);
 
-	get_hvpcibus(hbus);
-	queue_work(hbus->wq, &dr_wrk->wrk);
+	if (pending_dr) {
+		kfree(dr_wrk);
+	} else {
+		get_hvpcibus(hbus);
+		queue_work(hbus->wq, &dr_wrk->wrk);
+	}
 }
 
 /**
-- 
2.7.4

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                 reply	other threads:[~2018-03-15 14:22 UTC|newest]

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