| Message ID | 20180306182128.23281-5-decui@microsoft.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
> -----Original Message----- > From: Dexuan Cui > Sent: Tuesday, March 6, 2018 10:22 AM > To: bhelgaas@google.com; linux-pci@vger.kernel.org; KY Srinivasan <kys@microsoft.com>; > Stephen Hemminger <sthemmin@microsoft.com>; olaf@aepfle.de; apw@canonical.com; > jasowang@redhat.com > Cc: linux-kernel@vger.kernel.org; driverdev-devel@linuxdriverproject.org; Haiyang Zhang > <haiyangz@microsoft.com>; vkuznets@redhat.com; marcelo.cerri@canonical.com; Michael > Kelley (EOSG) <Michael.H.Kelley@microsoft.com>; Dexuan Cui <decui@microsoft.com>; Jack > Morgenstein <jackm@mellanox.com>; stable@vger.kernel.org > Subject: [PATCH v3 4/6] PCI: hv: remove hbus->enum_sem > > Since we serialize the present/eject work items now, we don't need the > semaphore any more. > > This is suggested by Michael Kelley. > > Signed-off-by: Dexuan Cui <decui@microsoft.com> > Cc: Vitaly Kuznetsov <vkuznets@redhat.com> > Cc: Jack Morgenstein <jackm@mellanox.com> > Cc: stable@vger.kernel.org > Cc: Stephen Hemminger <sthemmin@microsoft.com> > Cc: K. Y. Srinivasan <kys@microsoft.com> > Cc: Michael Kelley (EOSG) <Michael.H.Kelley@microsoft.com> > --- > drivers/pci/host/pci-hyperv.c | 17 ++--------------- > 1 file changed, 2 insertions(+), 15 deletions(-) > Reviewed-by: Michael Kelley <mikelley@microsoft.com>
> -----Original Message----- > From: Dexuan Cui > Sent: Tuesday, March 6, 2018 1:22 PM > To: bhelgaas@google.com; linux-pci@vger.kernel.org; KY Srinivasan > <kys@microsoft.com>; Stephen Hemminger <sthemmin@microsoft.com>; > olaf@aepfle.de; apw@canonical.com; jasowang@redhat.com > Cc: linux-kernel@vger.kernel.org; driverdev-devel@linuxdriverproject.org; > Haiyang Zhang <haiyangz@microsoft.com>; vkuznets@redhat.com; > marcelo.cerri@canonical.com; Michael Kelley (EOSG) > <Michael.H.Kelley@microsoft.com>; Dexuan Cui <decui@microsoft.com>; Jack > Morgenstein <jackm@mellanox.com>; stable@vger.kernel.org > Subject: [PATCH v3 4/6] PCI: hv: remove hbus->enum_sem > > Since we serialize the present/eject work items now, we don't need the > semaphore any more. > > This is suggested by Michael Kelley. > > Signed-off-by: Dexuan Cui <decui@microsoft.com> > Cc: Vitaly Kuznetsov <vkuznets@redhat.com> > Cc: Jack Morgenstein <jackm@mellanox.com> > Cc: stable@vger.kernel.org > Cc: Stephen Hemminger <sthemmin@microsoft.com> > Cc: K. Y. Srinivasan <kys@microsoft.com> > Cc: Michael Kelley (EOSG) <Michael.H.Kelley@microsoft.com> > --- Acked-by: Haiyang Zhang <haiyangz@microsoft.com>
diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c index aaee41faf55f..3a385212f666 100644 --- a/drivers/pci/host/pci-hyperv.c +++ b/drivers/pci/host/pci-hyperv.c @@ -447,7 +447,6 @@ struct hv_pcibus_device { spinlock_t device_list_lock; /* Protect lists below */ void __iomem *cfg_addr; - struct semaphore enum_sem; struct list_head resources_for_children; struct list_head children; @@ -1592,12 +1591,8 @@ static struct hv_pci_dev *get_pcichild_wslot(struct hv_pcibus_device *hbus, * It must also treat the omission of a previously observed device as * notification that the device no longer exists. * - * Note that this function is a work item, and it may not be - * invoked in the order that it was queued. Back to back - * updates of the list of present devices may involve queuing - * multiple work items, and this one may run before ones that - * were sent later. As such, this function only does something - * if is the last one in the queue. + * Note that this function is serialized with hv_eject_device_work(), + * because both are pushed to the ordered workqueue hbus->wq. */ static void pci_devices_present_work(struct work_struct *work) { @@ -1618,11 +1613,6 @@ static void pci_devices_present_work(struct work_struct *work) INIT_LIST_HEAD(&removed); - if (down_interruptible(&hbus->enum_sem)) { - put_hvpcibus(hbus); - return; - } - /* Pull this off the queue and process it if it was the last one. */ spin_lock_irqsave(&hbus->device_list_lock, flags); while (!list_empty(&hbus->dr_list)) { @@ -1639,7 +1629,6 @@ static void pci_devices_present_work(struct work_struct *work) spin_unlock_irqrestore(&hbus->device_list_lock, flags); if (!dr) { - up(&hbus->enum_sem); put_hvpcibus(hbus); return; } @@ -1726,7 +1715,6 @@ static void pci_devices_present_work(struct work_struct *work) break; } - up(&hbus->enum_sem); put_hvpcibus(hbus); kfree(dr); } @@ -2460,7 +2448,6 @@ static int hv_pci_probe(struct hv_device *hdev, spin_lock_init(&hbus->config_lock); spin_lock_init(&hbus->device_list_lock); spin_lock_init(&hbus->retarget_msi_interrupt_lock); - sema_init(&hbus->enum_sem, 1); init_completion(&hbus->remove_event); hbus->wq = alloc_ordered_workqueue("hv_pci_%x", 0, hbus->sysdata.domain);
Since we serialize the present/eject work items now, we don't need the semaphore any more. This is suggested by Michael Kelley. Signed-off-by: Dexuan Cui <decui@microsoft.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Jack Morgenstein <jackm@mellanox.com> Cc: stable@vger.kernel.org Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: K. Y. Srinivasan <kys@microsoft.com> Cc: Michael Kelley (EOSG) <Michael.H.Kelley@microsoft.com> --- drivers/pci/host/pci-hyperv.c | 17 ++--------------- 1 file changed, 2 insertions(+), 15 deletions(-)