Messages in this thread | | | From | "Tian, Kevin" <> | Subject | RE: [PATCH 06/12] iommu/vt-d: Acquiring lock in domain ID allocation helpers | Date | Wed, 1 Jun 2022 09:09:04 +0000 |
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> From: Lu Baolu <baolu.lu@linux.intel.com> > Sent: Friday, May 27, 2022 2:30 PM > > The iommu->lock is used to protect the per-IOMMU domain ID resource. > Move the spinlock acquisition/release into the helpers where domain > IDs are allocated and freed. The device_domain_lock is irrelevant to > domain ID resources, remove its assertion as well.
while moving the lock you also replace spin_lock_irqsave() with spin_lock(). It'd be cleaner to just do movement here and then replace all _irqsave() in patch 8.
> > Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> > --- > drivers/iommu/intel/iommu.c | 25 +++++++++---------------- > 1 file changed, 9 insertions(+), 16 deletions(-) > > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c > index 2d5f02b85de8..0da937ce0534 100644 > --- a/drivers/iommu/intel/iommu.c > +++ b/drivers/iommu/intel/iommu.c > @@ -1774,16 +1774,13 @@ static struct dmar_domain > *alloc_domain(unsigned int type) > return domain; > } > > -/* Must be called with iommu->lock */ > static int domain_attach_iommu(struct dmar_domain *domain, > struct intel_iommu *iommu) > { > unsigned long ndomains; > - int num; > - > - assert_spin_locked(&device_domain_lock); > - assert_spin_locked(&iommu->lock); > + int num, ret = 0; > > + spin_lock(&iommu->lock); > domain->iommu_refcnt[iommu->seq_id] += 1; > if (domain->iommu_refcnt[iommu->seq_id] == 1) { > ndomains = cap_ndoms(iommu->cap); > @@ -1792,7 +1789,8 @@ static int domain_attach_iommu(struct > dmar_domain *domain, > if (num >= ndomains) { > pr_err("%s: No free domain ids\n", iommu->name); > domain->iommu_refcnt[iommu->seq_id] -= 1; > - return -ENOSPC; > + ret = -ENOSPC; > + goto out_unlock; > } > > set_bit(num, iommu->domain_ids); > @@ -1801,7 +1799,9 @@ static int domain_attach_iommu(struct > dmar_domain *domain, > domain_update_iommu_cap(domain); > } > > - return 0; > +out_unlock: > + spin_unlock(&iommu->lock); > + return ret; > } > > static void domain_detach_iommu(struct dmar_domain *domain, > @@ -1809,9 +1809,7 @@ static void domain_detach_iommu(struct > dmar_domain *domain, > { > int num; > > - assert_spin_locked(&device_domain_lock); > - assert_spin_locked(&iommu->lock); > - > + spin_lock(&iommu->lock); > domain->iommu_refcnt[iommu->seq_id] -= 1; > if (domain->iommu_refcnt[iommu->seq_id] == 0) { > num = domain->iommu_did[iommu->seq_id]; > @@ -1819,6 +1817,7 @@ static void domain_detach_iommu(struct > dmar_domain *domain, > domain_update_iommu_cap(domain); > domain->iommu_did[iommu->seq_id] = 0; > } > + spin_unlock(&iommu->lock); > } > > static inline int guestwidth_to_adjustwidth(int gaw) > @@ -2471,9 +2470,7 @@ static int domain_add_dev_info(struct > dmar_domain *domain, struct device *dev) > > spin_lock_irqsave(&device_domain_lock, flags); > info->domain = domain; > - spin_lock(&iommu->lock); > ret = domain_attach_iommu(domain, iommu); > - spin_unlock(&iommu->lock); > if (ret) { > spin_unlock_irqrestore(&device_domain_lock, flags); > return ret; > @@ -4158,7 +4155,6 @@ static void __dmar_remove_one_dev_info(struct > device_domain_info *info) > { > struct dmar_domain *domain; > struct intel_iommu *iommu; > - unsigned long flags; > > assert_spin_locked(&device_domain_lock); > > @@ -4179,10 +4175,7 @@ static void __dmar_remove_one_dev_info(struct > device_domain_info *info) > } > > list_del(&info->link); > - > - spin_lock_irqsave(&iommu->lock, flags); > domain_detach_iommu(domain, iommu); > - spin_unlock_irqrestore(&iommu->lock, flags); > } > > static void dmar_remove_one_dev_info(struct device *dev) > -- > 2.25.1
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