From 948373b3ed1bcf05a237c24675b84804315aff14 Mon Sep 17 00:00:00 2001 From: Dexuan Cui Date: Thu, 15 Mar 2018 14:22:00 +0000 Subject: [PATCH] PCI: hv: Only queue new work items in hv_pci_devices_present() if necessary If there is pending work in hv_pci_devices_present() we just need to add the new dr entry into the dr_list. Add a check to detect pending work items and update the code to skip queuing work if pending work items are detected. Signed-off-by: Dexuan Cui [lorenzo.pieralisi@arm.com: updated commit log] Signed-off-by: Lorenzo Pieralisi Reviewed-by: Michael Kelley Acked-by: Haiyang Zhang Cc: Vitaly Kuznetsov Cc: Jack Morgenstein Cc: Stephen Hemminger Cc: K. Y. Srinivasan --- 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); + } } /**