Messages in this thread Patch in this message | | | From | Andy Shevchenko <> | Date | Fri, 16 Aug 2019 00:17:44 +0300 | Subject | Re: [PATCH v5 16/19] iommu/vt-d: Misc macro clean up for SVM |
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On Thu, Aug 15, 2019 at 11:52 PM Jacob Pan <jacob.jun.pan@linux.intel.com> wrote: > > Use combined macros for_each_svm_dev() to simplify SVM device iteration > and error checking. > > Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> > Reviewed-by: Eric Auger <eric.auger@redhat.com> > --- > drivers/iommu/intel-svm.c | 85 +++++++++++++++++++++++------------------------ > 1 file changed, 41 insertions(+), 44 deletions(-) > > diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c > index 5a688a5..ea6f2e2 100644 > --- a/drivers/iommu/intel-svm.c > +++ b/drivers/iommu/intel-svm.c > @@ -218,6 +218,10 @@ static const struct mmu_notifier_ops intel_mmuops = { > static DEFINE_MUTEX(pasid_mutex); > static LIST_HEAD(global_svm_list); > > +#define for_each_svm_dev(svm, dev) \ > + list_for_each_entry(sdev, &svm->devs, list) \
> + if (dev == sdev->dev) \
This should be if (dev != sdev->dev) {} else and no trailing \ is neeeded.
The rationale of above form to avoid for_each_foo() { } else { ...WTF?!.. }
> + > int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_ops *ops) > { > struct intel_iommu *iommu = intel_svm_device_to_iommu(dev); > @@ -263,15 +267,13 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_ > goto out; > } > > - list_for_each_entry(sdev, &svm->devs, list) { > - if (dev == sdev->dev) { > - if (sdev->ops != ops) { > - ret = -EBUSY; > - goto out; > - } > - sdev->users++; > - goto success; > + for_each_svm_dev(svm, dev) { > + if (sdev->ops != ops) { > + ret = -EBUSY; > + goto out; > } > + sdev->users++; > + goto success; > } > > break; > @@ -408,48 +410,43 @@ int intel_svm_unbind_mm(struct device *dev, int pasid) > goto out; > > svm = ioasid_find(NULL, pasid, NULL); > - if (IS_ERR(svm)) { > + if (IS_ERR_OR_NULL(svm)) { > ret = PTR_ERR(svm); > goto out; > } > > - if (!svm) > - goto out; > + for_each_svm_dev(svm, dev) { > + ret = 0; > + sdev->users--; > + if (!sdev->users) { > + list_del_rcu(&sdev->list); > + /* Flush the PASID cache and IOTLB for this device. > + * Note that we do depend on the hardware *not* using > + * the PASID any more. Just as we depend on other > + * devices never using PASIDs that they have no right > + * to use. We have a *shared* PASID table, because it's > + * large and has to be physically contiguous. So it's > + * hard to be as defensive as we might like. */ > + intel_pasid_tear_down_entry(iommu, dev, svm->pasid); > + intel_flush_svm_range_dev(svm, sdev, 0, -1, 0, !svm->mm); > + kfree_rcu(sdev, rcu); > + > + if (list_empty(&svm->devs)) { > + ioasid_free(svm->pasid); > + if (svm->mm) > + mmu_notifier_unregister(&svm->notifier, svm->mm); > > - list_for_each_entry(sdev, &svm->devs, list) { > - if (dev == sdev->dev) { > - ret = 0; > - sdev->users--; > - if (!sdev->users) { > - list_del_rcu(&sdev->list); > - /* Flush the PASID cache and IOTLB for this device. > - * Note that we do depend on the hardware *not* using > - * the PASID any more. Just as we depend on other > - * devices never using PASIDs that they have no right > - * to use. We have a *shared* PASID table, because it's > - * large and has to be physically contiguous. So it's > - * hard to be as defensive as we might like. */ > - intel_pasid_tear_down_entry(iommu, dev, svm->pasid); > - intel_flush_svm_range_dev(svm, sdev, 0, -1, 0, !svm->mm); > - kfree_rcu(sdev, rcu); > - > - if (list_empty(&svm->devs)) { > - ioasid_free(svm->pasid); > - if (svm->mm) > - mmu_notifier_unregister(&svm->notifier, svm->mm); > - > - list_del(&svm->list); > - > - /* We mandate that no page faults may be outstanding > - * for the PASID when intel_svm_unbind_mm() is called. > - * If that is not obeyed, subtle errors will happen. > - * Let's make them less subtle... */ > - memset(svm, 0x6b, sizeof(*svm)); > - kfree(svm); > - } > + list_del(&svm->list); > + > + /* We mandate that no page faults may be outstanding > + * for the PASID when intel_svm_unbind_mm() is called. > + * If that is not obeyed, subtle errors will happen. > + * Let's make them less subtle... */ > + memset(svm, 0x6b, sizeof(*svm)); > + kfree(svm); > } > - break; > } > + break; > } > out: > mutex_unlock(&pasid_mutex); > @@ -585,7 +582,7 @@ static irqreturn_t prq_event_thread(int irq, void *d) > * to unbind the mm while any page faults are outstanding. > * So we only need RCU to protect the internal idr code. */ > rcu_read_unlock(); > - if (IS_ERR(svm) || !svm) { > + if (IS_ERR_OR_NULL(svm)) { > pr_err("%s: Page request for invalid PASID %d: %08llx %08llx\n", > iommu->name, req->pasid, ((unsigned long long *)req)[0], > ((unsigned long long *)req)[1]); > -- > 2.7.4 >
-- With Best Regards, Andy Shevchenko
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