Use rculist for list of devices attached by a domain. And use the RCU lock for read/write protection. As both the global device_domain array and per-domain device_domain list are protected by RCU lock now, there is no need to use the spinlock anymore. Cleanup device_domain_lock.
Signed-off-by: Lu Baolu <[email protected]> --- include/linux/intel-iommu.h | 2 +- drivers/iommu/intel/debugfs.c | 11 +-- drivers/iommu/intel/iommu.c | 126 ++++++++++++++-------------------- 3 files changed, 53 insertions(+), 86 deletions(-) diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h index aca1c1cc04a8..286bd6f82024 100644 --- a/include/linux/intel-iommu.h +++ b/include/linux/intel-iommu.h @@ -480,7 +480,6 @@ enum { #define VTD_FLAG_SVM_CAPABLE (1 << 2) extern int intel_iommu_sm; -extern spinlock_t device_domain_lock; #define sm_supported(iommu) (intel_iommu_sm && ecap_smts((iommu)->ecap)) #define pasid_supported(iommu) (sm_supported(iommu) && \ @@ -609,6 +608,7 @@ struct intel_iommu { /* PCI domain-device relationship */ struct device_domain_info { + struct rcu_head rcu; struct list_head link; /* link to domain siblings */ struct list_head table; /* link to pasid table */ u32 segment; /* PCI segment number */ diff --git a/drivers/iommu/intel/debugfs.c b/drivers/iommu/intel/debugfs.c index ed796eea4581..6a115103412a 100644 --- a/drivers/iommu/intel/debugfs.c +++ b/drivers/iommu/intel/debugfs.c @@ -364,15 +364,8 @@ static int show_device_domain_translation(struct device *dev, void *data) static int domain_translation_struct_show(struct seq_file *m, void *unused) { - unsigned long flags; - int ret; - - spin_lock_irqsave(&device_domain_lock, flags); - ret = bus_for_each_dev(&pci_bus_type, NULL, m, - show_device_domain_translation); - spin_unlock_irqrestore(&device_domain_lock, flags); - - return ret; + return bus_for_each_dev(&pci_bus_type, NULL, m, + show_device_domain_translation); } DEFINE_SHOW_ATTRIBUTE(domain_translation_struct); diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index ecec923ce191..303d6d93e381 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -294,7 +294,6 @@ static LIST_HEAD(dmar_satc_units); /* bitmap for indexing intel_iommus */ static int g_num_of_iommus; -static void domain_remove_dev_info(struct dmar_domain *domain); static void dmar_remove_one_dev_info(struct device *dev); static void __dmar_remove_one_dev_info(struct device_domain_info *info); @@ -315,7 +314,6 @@ static int iommu_skip_te_disable; int intel_iommu_gfx_mapped; EXPORT_SYMBOL_GPL(intel_iommu_gfx_mapped); -DEFINE_SPINLOCK(device_domain_lock); static DEFINE_XARRAY_ALLOC(device_domain_array); /* Convert device source ID into the index of device_domain_array. */ @@ -597,12 +595,11 @@ static int domain_update_device_node(struct dmar_domain *domain) struct device_domain_info *info; int nid = NUMA_NO_NODE; - assert_spin_locked(&device_domain_lock); - if (list_empty(&domain->devices)) return NUMA_NO_NODE; - list_for_each_entry(info, &domain->devices, link) { + rcu_read_lock(); + list_for_each_entry_rcu(info, &domain->devices, link) { if (!info->dev) continue; @@ -616,6 +613,7 @@ static int domain_update_device_node(struct dmar_domain *domain) if (nid != NUMA_NO_NODE) break; } + rcu_read_unlock(); return nid; } @@ -1436,25 +1434,26 @@ static void __iommu_flush_iotlb(struct intel_iommu *iommu, u16 did, } static struct device_domain_info * -iommu_support_dev_iotlb (struct dmar_domain *domain, struct intel_iommu *iommu, - u8 bus, u8 devfn) +iommu_support_dev_iotlb(struct dmar_domain *domain, struct intel_iommu *iommu, + u8 bus, u8 devfn) { - struct device_domain_info *info; - - assert_spin_locked(&device_domain_lock); + struct device_domain_info *tmp, *info = NULL; if (!iommu->qi) return NULL; - list_for_each_entry(info, &domain->devices, link) - if (info->iommu == iommu && info->bus == bus && - info->devfn == devfn) { - if (info->ats_supported && info->dev) - return info; + rcu_read_lock(); + list_for_each_entry_rcu(tmp, &domain->devices, link) { + if (tmp->iommu == iommu && tmp->bus == bus && + tmp->devfn == devfn) { + if (tmp->ats_supported && tmp->dev) + info = tmp; break; } + } + rcu_read_unlock(); - return NULL; + return info; } static void domain_update_iotlb(struct dmar_domain *domain) @@ -1462,13 +1461,14 @@ static void domain_update_iotlb(struct dmar_domain *domain) struct device_domain_info *info; bool has_iotlb_device = false; - assert_spin_locked(&device_domain_lock); - - list_for_each_entry(info, &domain->devices, link) + rcu_read_lock(); + list_for_each_entry_rcu(info, &domain->devices, link) { if (info->ats_enabled) { has_iotlb_device = true; break; } + } + rcu_read_unlock(); domain->has_iotlb_device = has_iotlb_device; } @@ -1477,8 +1477,6 @@ static void iommu_enable_dev_iotlb(struct device_domain_info *info) { struct pci_dev *pdev; - assert_spin_locked(&device_domain_lock); - if (!info || !dev_is_pci(info->dev)) return; @@ -1524,8 +1522,6 @@ static void iommu_disable_dev_iotlb(struct device_domain_info *info) { struct pci_dev *pdev; - assert_spin_locked(&device_domain_lock); - if (!dev_is_pci(info->dev)) return; @@ -1565,17 +1561,15 @@ static void __iommu_flush_dev_iotlb(struct device_domain_info *info, static void iommu_flush_dev_iotlb(struct dmar_domain *domain, u64 addr, unsigned mask) { - unsigned long flags; struct device_domain_info *info; if (!domain->has_iotlb_device) return; - spin_lock_irqsave(&device_domain_lock, flags); - list_for_each_entry(info, &domain->devices, link) + rcu_read_lock(); + list_for_each_entry_rcu(info, &domain->devices, link) __iommu_flush_dev_iotlb(info, addr, mask); - - spin_unlock_irqrestore(&device_domain_lock, flags); + rcu_read_unlock(); } static void iommu_flush_iotlb_psi(struct intel_iommu *iommu, @@ -1820,7 +1814,7 @@ static struct dmar_domain *alloc_domain(unsigned int type) if (first_level_by_default(type)) domain->flags |= DOMAIN_FLAG_USE_FIRST_LEVEL; domain->has_iotlb_device = false; - INIT_LIST_HEAD(&domain->devices); + INIT_LIST_HEAD_RCU(&domain->devices); return domain; } @@ -1832,7 +1826,6 @@ static int domain_attach_iommu(struct dmar_domain *domain, unsigned long ndomains; int num; - assert_spin_locked(&device_domain_lock); assert_spin_locked(&iommu->lock); domain->iommu_refcnt[iommu->seq_id] += 1; @@ -1860,7 +1853,6 @@ static void domain_detach_iommu(struct dmar_domain *domain, { int num; - assert_spin_locked(&device_domain_lock); assert_spin_locked(&iommu->lock); domain->iommu_refcnt[iommu->seq_id] -= 1; @@ -1889,8 +1881,15 @@ static inline int guestwidth_to_adjustwidth(int gaw) static void domain_exit(struct dmar_domain *domain) { - /* Remove associated devices and clear attached or cached domains */ - domain_remove_dev_info(domain); + struct device_domain_info *info, *tmp; + + /* + * Remove associated devices and clear attached or cached domains. + * No worries about new devices insertion or removal. Hence no need + * for a lock here. + */ + list_for_each_entry_safe(info, tmp, &domain->devices, link) + __dmar_remove_one_dev_info(info); if (domain->pgd) { LIST_HEAD(freelist); @@ -1973,9 +1972,7 @@ static int domain_context_mapping_one(struct dmar_domain *domain, BUG_ON(!domain->pgd); - spin_lock_irqsave(&device_domain_lock, flags); - spin_lock(&iommu->lock); - + spin_lock_irqsave(&iommu->lock, flags); ret = -ENOMEM; context = iommu_context_addr(iommu, bus, devfn, 1); if (!context) @@ -2094,8 +2091,7 @@ static int domain_context_mapping_one(struct dmar_domain *domain, ret = 0; out_unlock: - spin_unlock(&iommu->lock); - spin_unlock_irqrestore(&device_domain_lock, flags); + spin_unlock_irqrestore(&iommu->lock, flags); return ret; } @@ -2382,17 +2378,6 @@ static void domain_context_clear_one(struct device_domain_info *info, u8 bus, u8 __iommu_flush_dev_iotlb(info, 0, MAX_AGAW_PFN_WIDTH); } -static void domain_remove_dev_info(struct dmar_domain *domain) -{ - struct device_domain_info *info, *tmp; - unsigned long flags; - - spin_lock_irqsave(&device_domain_lock, flags); - list_for_each_entry_safe(info, tmp, &domain->devices, link) - __dmar_remove_one_dev_info(info); - spin_unlock_irqrestore(&device_domain_lock, flags); -} - static int domain_setup_first_level(struct intel_iommu *iommu, struct dmar_domain *domain, struct device *dev, @@ -2444,17 +2429,14 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu, unsigned long flags; int ret; - spin_lock_irqsave(&device_domain_lock, flags); - info->domain = domain; - spin_lock(&iommu->lock); + spin_lock_irqsave(&iommu->lock, flags); ret = domain_attach_iommu(domain, iommu); - spin_unlock(&iommu->lock); - if (ret) { - spin_unlock_irqrestore(&device_domain_lock, flags); + spin_unlock_irqrestore(&iommu->lock, flags); + if (ret) return NULL; - } - list_add(&info->link, &domain->devices); - spin_unlock_irqrestore(&device_domain_lock, flags); + + info->domain = domain; + list_add_rcu(&info->link, &domain->devices); /* PASID table is mandatory for a PCI device in scalable mode. */ if (dev && dev_is_pci(dev) && sm_supported(iommu)) { @@ -4182,8 +4164,6 @@ static void __dmar_remove_one_dev_info(struct device_domain_info *info) struct intel_iommu *iommu; unsigned long flags; - assert_spin_locked(&device_domain_lock); - if (WARN_ON(!info)) return; @@ -4191,16 +4171,19 @@ static void __dmar_remove_one_dev_info(struct device_domain_info *info) domain = info->domain; if (info->dev && !dev_is_real_dma_subdevice(info->dev)) { - if (dev_is_pci(info->dev) && sm_supported(iommu)) + if (dev_is_pci(info->dev) && sm_supported(iommu)) { + spin_lock_irqsave(&iommu->lock, flags); intel_pasid_tear_down_entry(iommu, info->dev, PASID_RID2PASID, false); + spin_unlock_irqrestore(&iommu->lock, flags); + } iommu_disable_dev_iotlb(info); domain_context_clear(info); intel_pasid_free_table(info->dev); } - list_del(&info->link); + list_del_rcu(&info->link); spin_lock_irqsave(&iommu->lock, flags); domain_detach_iommu(domain, iommu); @@ -4210,13 +4193,10 @@ static void __dmar_remove_one_dev_info(struct device_domain_info *info) static void dmar_remove_one_dev_info(struct device *dev) { struct device_domain_info *info; - unsigned long flags; - spin_lock_irqsave(&device_domain_lock, flags); info = dev_iommu_priv_get(dev); if (info) __dmar_remove_one_dev_info(info); - spin_unlock_irqrestore(&device_domain_lock, flags); } static int md_domain_init(struct dmar_domain *domain, int guest_width) @@ -4529,6 +4509,7 @@ static struct iommu_device *intel_iommu_probe_device(struct device *dev) info->dev = dev; info->iommu = iommu; + init_rcu_head(&info->rcu); if (dev_is_pci(dev)) { if (ecap_dev_iotlb_support(iommu->ecap) && pci_ats_supported(pdev) && @@ -4553,7 +4534,7 @@ static struct iommu_device *intel_iommu_probe_device(struct device *dev) devi_idx(info->segment, info->bus, info->devfn), info, GFP_KERNEL); if (xa_err(curr) || WARN_ON(curr)) { - kfree(info); + kfree_rcu(info, rcu); return ERR_PTR(-ENOSPC); } @@ -4565,17 +4546,13 @@ static struct iommu_device *intel_iommu_probe_device(struct device *dev) static void intel_iommu_release_device(struct device *dev) { struct device_domain_info *info = dev_iommu_priv_get(dev); - unsigned long flags; dmar_remove_one_dev_info(dev); - spin_lock_irqsave(&device_domain_lock, flags); dev_iommu_priv_set(dev, NULL); xa_erase(&device_domain_array, devi_idx(info->segment, info->bus, info->devfn)); - spin_unlock_irqrestore(&device_domain_lock, flags); - - kfree(info); + kfree_rcu(info, rcu); set_dma_ops(dev, NULL); } @@ -4655,9 +4632,7 @@ int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct device *dev) if (!domain) return -EINVAL; - spin_lock_irqsave(&device_domain_lock, flags); - spin_lock(&iommu->lock); - + spin_lock_irqsave(&iommu->lock, flags); ret = -EINVAL; if (!info->pasid_supported) goto out; @@ -4686,8 +4661,7 @@ int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct device *dev) ret = 0; out: - spin_unlock(&iommu->lock); - spin_unlock_irqrestore(&device_domain_lock, flags); + spin_unlock_irqrestore(&iommu->lock, flags); return ret; } -- 2.25.1 _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
