From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-sg2apc01on0120.outbound.protection.outlook.com ([104.47.125.120]:45036 "EHLO APC01-SG2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752910AbeCFSWE (ORCPT ); Tue, 6 Mar 2018 13:22:04 -0500 From: Dexuan Cui To: "bhelgaas@google.com" , "linux-pci@vger.kernel.org" , KY Srinivasan , Stephen Hemminger , "olaf@aepfle.de" , "apw@canonical.com" , "jasowang@redhat.com" CC: "linux-kernel@vger.kernel.org" , "driverdev-devel@linuxdriverproject.org" , Haiyang Zhang , "vkuznets@redhat.com" , "marcelo.cerri@canonical.com" , "Michael Kelley (EOSG)" , Dexuan Cui , Jack Morgenstein , "stable@vger.kernel.org" Subject: [PATCH v3 4/6] PCI: hv: remove hbus->enum_sem Date: Tue, 6 Mar 2018 18:21:53 +0000 Message-ID: <20180306182128.23281-5-decui@microsoft.com> References: <20180306182128.23281-1-decui@microsoft.com> In-Reply-To: <20180306182128.23281-1-decui@microsoft.com> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org List-ID: 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 Cc: Vitaly Kuznetsov Cc: Jack Morgenstein Cc: stable@vger.kernel.org Cc: Stephen Hemminger Cc: K. Y. Srinivasan Cc: Michael Kelley (EOSG) --- drivers/pci/host/pci-hyperv.c | 17 ++--------------- 1 file changed, 2 insertions(+), 15 deletions(-) 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; =20 - struct semaphore enum_sem; struct list_head resources_for_children; =20 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_str= uct *work) =20 INIT_LIST_HEAD(&removed); =20 - 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_stru= ct *work) spin_unlock_irqrestore(&hbus->device_list_lock, flags); =20 if (!dr) { - up(&hbus->enum_sem); put_hvpcibus(hbus); return; } @@ -1726,7 +1715,6 @@ static void pci_devices_present_work(struct work_stru= ct *work) break; } =20 - 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 =3D alloc_ordered_workqueue("hv_pci_%x", 0, hbus->sysdata.domain); --=20 2.7.4