/* * Common code for control of lockd and nfsv4 grace periods. * * Transplanted from lockd code */ #include #include #include #include static unsigned int grace_net_id; static DEFINE_SPINLOCK(grace_lock); /** * locks_start_grace * @net: net namespace that this lock manager belongs to * @lm: who this grace period is for * * A grace period is a period during which locks should not be given * out. Currently grace periods are only enforced by the two lock * managers (lockd and nfsd), using the locks_in_grace() function to * check when they are in a grace period. * * This function is called to start a grace period. */ void locks_start_grace(struct net *net, struct lock_manager *lm) { struct list_head *grace_list = net_generic(net, grace_net_id); spin_lock(&grace_lock); list_add(&lm->list, grace_list); spin_unlock(&grace_lock); } EXPORT_SYMBOL_GPL(locks_start_grace); /** * locks_end_grace * @net: net namespace that this lock manager belongs to * @lm: who this grace period is for * * Call this function to state that the given lock manager is ready to * resume regular locking. The grace period will not end until all lock * managers that called locks_start_grace() also call locks_end_grace(). * Note that callers count on it being safe to call this more than once, * and the second call should be a no-op. */ void locks_end_grace(struct lock_manager *lm) { spin_lock(&grace_lock); list_del_init(&lm->list); spin_unlock(&grace_lock); } EXPORT_SYMBOL_GPL(locks_end_grace); /** * locks_in_grace * * Lock managers call this function to determine when it is OK for them * to answer ordinary lock requests, and when they should accept only * lock reclaims. */ int __state_in_grace(struct net *net, bool open) { struct list_head *grace_list = net_generic(net, grace_net_id); struct lock_manager *lm; if (!open) return !list_empty(grace_list); list_for_each_entry(lm, grace_list, list) { if (lm->block_opens) return true; } return false; } int locks_in_grace(struct net *net) { return __state_in_grace(net, 0); } EXPORT_SYMBOL_GPL(locks_in_grace); int opens_in_grace(struct net *net) { return __state_in_grace(net, 1); } EXPORT_SYMBOL_GPL(opens_in_grace); static int __net_init grace_init_net(struct net *net) { struct list_head *grace_list = net_generic(net, grace_net_id); INIT_LIST_HEAD(grace_list); return 0; } static void __net_exit grace_exit_net(struct net *net) { struct list_head *grace_list = net_generic(net, grace_net_id); BUG_ON(!list_empty(grace_list)); } static struct pernet_operations grace_net_ops = { .init = grace_init_net, .exit = grace_exit_net, .id = &grace_net_id, .size = sizeof(struct list_head), }; static int __init init_grace(void) { return register_pernet_subsys(&grace_net_ops); } static void __exit exit_grace(void) { unregister_pernet_subsys(&grace_net_ops); } MODULE_AUTHOR("Jeff Layton "); MODULE_LICENSE("GPL"); module_init(init_grace) module_exit(exit_grace) arch/x86
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authorBjorn Helgaas <bhelgaas@google.com>2017-01-27 15:00:45 -0600
committerBjorn Helgaas <bhelgaas@google.com>2017-01-27 15:00:45 -0600
commit030305d69fc6963c16003f50d7e8d74b02d0a143 (patch)
tree363a4e34d199178769b7e7eeb26ea2620a55847b /tools/perf/arch/x86
parent4d191b1b63c209e37bf27938ef365244d3c41084 (diff)
PCI/ASPM: Handle PCI-to-PCIe bridges as roots of PCIe hierarchies
In a struct pcie_link_state, link->root points to the pcie_link_state of the root of the PCIe hierarchy. For the topmost link, this points to itself (link->root = link). For others, we copy the pointer from the parent (link->root = link->parent->root). Previously we recognized that Root Ports originated PCIe hierarchies, but we treated PCI/PCI-X to PCIe Bridges as being in the middle of the hierarchy, and when we tried to copy the pointer from link->parent->root, there was no parent, and we dereferenced a NULL pointer: BUG: unable to handle kernel NULL pointer dereference at 0000000000000090 IP: [<ffffffff9e424350>] pcie_aspm_init_link_state+0x170/0x820 Recognize that PCI/PCI-X to PCIe Bridges originate PCIe hierarchies just like Root Ports do, so link->root for these devices should also point to itself. Fixes: 51ebfc92b72b ("PCI: Enumerate switches below PCI-to-PCIe bridges") Link: https://bugzilla.kernel.org/show_bug.cgi?id=193411 Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1022181 Tested-by: lists@ssl-mail.com Tested-by: Jayachandran C. <jnair@caviumnetworks.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org # v4.2+
Diffstat (limited to 'tools/perf/arch/x86')