From b9443f401bb20ae6414e3e68bca0413bad28b689 Mon Sep 17 00:00:00 2001 From: Feng Tang Date: Thu, 23 Aug 2012 15:45:03 +0800 Subject: [PATCH] PCI: Use pci_device_id on stack for pci_get_subsys/class() to avoid kmalloc This fixes a kernel warning https://lkml.org/lkml/2012/7/31/682 pci_get_subsys() may get called in late system reboot stage, using a sleepable kmalloc() sounds fragile and will cause a kernel warning with my recent commmit 55c844a "x86/reboot: Fix a warning message triggered by stop_other_cpus()" which disable local interrupt in late system shutdown/reboot phase. Using a local parameter instead will fix it and make it eligible for calling from atomic context. Do the same change for the pci_get_class() as suggested by Bjorn Helgaas. Initializing the on-stack struct pci_device_id suggested by Fengguang Wu and Jiri Slaby. Section 6.7.8 of the C99 standard guarantees that when we initialize some of the struct members, the rest of the struct is implicitly initialized the same as objects with static storage duration, i.e., to zero in this case. [bhelgaas: changelog, incorporate Fengguang/Jiri initialization fix] Bisected-by: Fengguang Wu Signed-off-by: Feng Tang Signed-off-by: Jiri Slaby Signed-off-by: Bjorn Helgaas Reviewed-by: Fengguang Wu --- drivers/pci/search.c | 44 +++++++++++++++++--------------------------- 1 file changed, 17 insertions(+), 27 deletions(-) diff --git a/drivers/pci/search.c b/drivers/pci/search.c index 993d4a0a2469..9148b6e8056b 100644 --- a/drivers/pci/search.c +++ b/drivers/pci/search.c @@ -245,8 +245,12 @@ struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device, unsigned int ss_vendor, unsigned int ss_device, struct pci_dev *from) { - struct pci_dev *pdev; - struct pci_device_id *id; + struct pci_device_id id = { + .vendor = vendor, + .device = device, + .subvendor = ss_vendor, + .subdevice = ss_device, + }; /* * pci_find_subsys() can be called on the ide_setup() path, @@ -257,18 +261,7 @@ struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device, if (unlikely(no_pci_devices())) return NULL; - id = kzalloc(sizeof(*id), GFP_KERNEL); - if (!id) - return NULL; - id->vendor = vendor; - id->device = device; - id->subvendor = ss_vendor; - id->subdevice = ss_device; - - pdev = pci_get_dev_by_id(id, from); - kfree(id); - - return pdev; + return pci_get_dev_by_id(&id, from); } /** @@ -307,19 +300,16 @@ pci_get_device(unsigned int vendor, unsigned int device, struct pci_dev *from) */ struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from) { - struct pci_dev *dev; - struct pci_device_id *id; - - id = kzalloc(sizeof(*id), GFP_KERNEL); - if (!id) - return NULL; - id->vendor = id->device = id->subvendor = id->subdevice = PCI_ANY_ID; - id->class_mask = PCI_ANY_ID; - id->class = class; - - dev = pci_get_dev_by_id(id, from); - kfree(id); - return dev; + struct pci_device_id id = { + .vendor = PCI_ANY_ID, + .device = PCI_ANY_ID, + .subvendor = PCI_ANY_ID, + .subdevice = PCI_ANY_ID, + .class_mask = PCI_ANY_ID, + .class = class, + }; + + return pci_get_dev_by_id(&id, from); } /** -- 2.39.5