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Groups > linux.kernel > #1518921 > unrolled thread
| Started by | Dexuan Cui <decui@microsoft.com> |
|---|---|
| First post | 2016-11-10 13:00 +0100 |
| Last post | 2016-11-15 00:10 +0100 |
| Articles | 3 — 3 participants |
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[PATCH 3/3] PCI: hv: delete the device earlier from hbus->children for hot-remove Dexuan Cui <decui@microsoft.com> - 2016-11-10 13:00 +0100
RE: [PATCH 3/3] PCI: hv: delete the device earlier from hbus->children for hot-remove Jake Oshins <jakeo@microsoft.com> - 2016-11-12 01:50 +0100
RE: [PATCH 3/3] PCI: hv: delete the device earlier from hbus->children for hot-remove KY Srinivasan <kys@microsoft.com> - 2016-11-15 00:10 +0100
| From | Dexuan Cui <decui@microsoft.com> |
|---|---|
| Date | 2016-11-10 13:00 +0100 |
| Subject | [PATCH 3/3] PCI: hv: delete the device earlier from hbus->children for hot-remove |
| Message-ID | <sBWbp-5Fm-55@gated-at.bofh.it> |
After we send a PCI_EJECTION_COMPLETE message to the host, the host will immediately send us a PCI_BUS_RELATIONS message with relations->device_count == 0, so pci_devices_present_work(), running on another thread, can find the being-ejected device, mark the hpdev->reported_missing to true, and run list_move_tail()/list_del() for the device -- this races hv_eject_device_work() -> list_del(). The patch moves the list_del() in hv_eject_device_work() to an earlier place, i.e. before we send PCI_EJECTION_COMPLETE, so later the pci_devices_present_work() can't see the device. Signed-off-by: Dexuan Cui <decui@microsoft.com> CC: Jake Oshins <jakeo@microsoft.com> Cc: KY Srinivasan <kys@microsoft.com> CC: Haiyang Zhang <haiyangz@microsoft.com> CC: Vitaly Kuznetsov <vkuznets@redhat.com> --- drivers/pci/host/pci-hyperv.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c index 7590ad0..fe5179d 100644 --- a/drivers/pci/host/pci-hyperv.c +++ b/drivers/pci/host/pci-hyperv.c @@ -1582,6 +1582,10 @@ static void hv_eject_device_work(struct work_struct *work) pci_dev_put(pdev); } + spin_lock_irqsave(&hpdev->hbus->device_list_lock, flags); + list_del(&hpdev->list_entry); + spin_unlock_irqrestore(&hpdev->hbus->device_list_lock, flags); + memset(&ctxt, 0, sizeof(ctxt)); ejct_pkt = (struct pci_eject_response *)&ctxt.pkt.message; ejct_pkt->message_type.type = PCI_EJECTION_COMPLETE; @@ -1590,10 +1594,6 @@ static void hv_eject_device_work(struct work_struct *work) sizeof(*ejct_pkt), (unsigned long)&ctxt.pkt, VM_PKT_DATA_INBAND, 0); - spin_lock_irqsave(&hpdev->hbus->device_list_lock, flags); - list_del(&hpdev->list_entry); - spin_unlock_irqrestore(&hpdev->hbus->device_list_lock, flags); - put_pcichild(hpdev, hv_pcidev_ref_childlist); put_pcichild(hpdev, hv_pcidev_ref_pnp); put_hvpcibus(hpdev->hbus); -- 2.7.4
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| From | Jake Oshins <jakeo@microsoft.com> |
|---|---|
| Date | 2016-11-12 01:50 +0100 |
| Subject | RE: [PATCH 3/3] PCI: hv: delete the device earlier from hbus->children for hot-remove |
| Message-ID | <sCuG5-3fd-5@gated-at.bofh.it> |
| In reply to | #1518921 |
> -----Original Message----- > From: Dexuan Cui > Sent: Wednesday, November 9, 2016 11:20 PM > To: Bjorn Helgaas <bhelgaas@google.com>; linux-pci@vger.kernel.org; > devel@linuxdriverproject.org > Cc: gregkh@linuxfoundation.org; KY Srinivasan <kys@microsoft.com>; > Haiyang Zhang <haiyangz@microsoft.com>; Stephen Hemminger > <sthemmin@microsoft.com>; Jake Oshins <jakeo@microsoft.com>; Hadden > Hoppert <haddenh@microsoft.com>; Vitaly Kuznetsov > <vkuznets@redhat.com>; jasowang@redhat.com; apw@canonical.com; > olaf@aepfle.de; linux-kernel@vger.kernel.org > Subject: [PATCH 3/3] PCI: hv: delete the device earlier from hbus->children > for hot-remove > > After we send a PCI_EJECTION_COMPLETE message to the host, the host will > immediately send us a PCI_BUS_RELATIONS message with > relations->device_count == 0, so pci_devices_present_work(), running on > another thread, can find the being-ejected device, mark > the hpdev->reported_missing to true, and run list_move_tail()/list_del() > for the device -- this races hv_eject_device_work() -> list_del(). > > The patch moves the list_del() in hv_eject_device_work() to an earlier > place, i.e. before we send PCI_EJECTION_COMPLETE, so later the > pci_devices_present_work() can't see the device. > > Signed-off-by: Dexuan Cui <decui@microsoft.com> > CC: Jake Oshins <jakeo@microsoft.com> > Cc: KY Srinivasan <kys@microsoft.com> > CC: Haiyang Zhang <haiyangz@microsoft.com> > CC: Vitaly Kuznetsov <vkuznets@redhat.com> > --- > drivers/pci/host/pci-hyperv.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c > index 7590ad0..fe5179d 100644 > --- a/drivers/pci/host/pci-hyperv.c > +++ b/drivers/pci/host/pci-hyperv.c > @@ -1582,6 +1582,10 @@ static void hv_eject_device_work(struct > work_struct *work) > pci_dev_put(pdev); > } > > + spin_lock_irqsave(&hpdev->hbus->device_list_lock, flags); > + list_del(&hpdev->list_entry); > + spin_unlock_irqrestore(&hpdev->hbus->device_list_lock, flags); > + > memset(&ctxt, 0, sizeof(ctxt)); > ejct_pkt = (struct pci_eject_response *)&ctxt.pkt.message; > ejct_pkt->message_type.type = PCI_EJECTION_COMPLETE; > @@ -1590,10 +1594,6 @@ static void hv_eject_device_work(struct > work_struct *work) > sizeof(*ejct_pkt), (unsigned long)&ctxt.pkt, > VM_PKT_DATA_INBAND, 0); > > - spin_lock_irqsave(&hpdev->hbus->device_list_lock, flags); > - list_del(&hpdev->list_entry); > - spin_unlock_irqrestore(&hpdev->hbus->device_list_lock, flags); > - > put_pcichild(hpdev, hv_pcidev_ref_childlist); > put_pcichild(hpdev, hv_pcidev_ref_pnp); > put_hvpcibus(hpdev->hbus); > -- > 2.7.4 This looks good, too. -- Jake Oshins
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| From | KY Srinivasan <kys@microsoft.com> |
|---|---|
| Date | 2016-11-15 00:10 +0100 |
| Subject | RE: [PATCH 3/3] PCI: hv: delete the device earlier from hbus->children for hot-remove |
| Message-ID | <sDyxY-55w-41@gated-at.bofh.it> |
| In reply to | #1518921 |
> -----Original Message----- > From: Dexuan Cui > Sent: Wednesday, November 9, 2016 11:20 PM > To: Bjorn Helgaas <bhelgaas@google.com>; linux-pci@vger.kernel.org; > devel@linuxdriverproject.org > Cc: gregkh@linuxfoundation.org; KY Srinivasan <kys@microsoft.com>; > Haiyang Zhang <haiyangz@microsoft.com>; Stephen Hemminger > <sthemmin@microsoft.com>; Jake Oshins <jakeo@microsoft.com>; Hadden > Hoppert <haddenh@microsoft.com>; Vitaly Kuznetsov > <vkuznets@redhat.com>; jasowang@redhat.com; apw@canonical.com; > olaf@aepfle.de; linux-kernel@vger.kernel.org > Subject: [PATCH 3/3] PCI: hv: delete the device earlier from hbus->children > for hot-remove > > After we send a PCI_EJECTION_COMPLETE message to the host, the host will > immediately send us a PCI_BUS_RELATIONS message with > relations->device_count == 0, so pci_devices_present_work(), running on > another thread, can find the being-ejected device, mark > the hpdev->reported_missing to true, and run list_move_tail()/list_del() > for the device -- this races hv_eject_device_work() -> list_del(). > > The patch moves the list_del() in hv_eject_device_work() to an earlier > place, i.e. before we send PCI_EJECTION_COMPLETE, so later the > pci_devices_present_work() can't see the device. > > Signed-off-by: Dexuan Cui <decui@microsoft.com> > CC: Jake Oshins <jakeo@microsoft.com> > Cc: KY Srinivasan <kys@microsoft.com> > CC: Haiyang Zhang <haiyangz@microsoft.com> > CC: Vitaly Kuznetsov <vkuznets@redhat.com> Thanks Dexuan. Acked-by: K. Y. Srinivasan <kys@microsoft.com> > --- > drivers/pci/host/pci-hyperv.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c > index 7590ad0..fe5179d 100644 > --- a/drivers/pci/host/pci-hyperv.c > +++ b/drivers/pci/host/pci-hyperv.c > @@ -1582,6 +1582,10 @@ static void hv_eject_device_work(struct > work_struct *work) > pci_dev_put(pdev); > } > > + spin_lock_irqsave(&hpdev->hbus->device_list_lock, flags); > + list_del(&hpdev->list_entry); > + spin_unlock_irqrestore(&hpdev->hbus->device_list_lock, flags); > + > memset(&ctxt, 0, sizeof(ctxt)); > ejct_pkt = (struct pci_eject_response *)&ctxt.pkt.message; > ejct_pkt->message_type.type = PCI_EJECTION_COMPLETE; > @@ -1590,10 +1594,6 @@ static void hv_eject_device_work(struct > work_struct *work) > sizeof(*ejct_pkt), (unsigned long)&ctxt.pkt, > VM_PKT_DATA_INBAND, 0); > > - spin_lock_irqsave(&hpdev->hbus->device_list_lock, flags); > - list_del(&hpdev->list_entry); > - spin_unlock_irqrestore(&hpdev->hbus->device_list_lock, flags); > - > put_pcichild(hpdev, hv_pcidev_ref_childlist); > put_pcichild(hpdev, hv_pcidev_ref_pnp); > put_hvpcibus(hpdev->hbus); > -- > 2.7.4
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