Re: [PATCH v5 8/8] iommu/vt-d: Misc macro clean up for SVM
On Mon, 02 Dec 2019 12:10:45 -0800
Joe Perches wrote:
> On Mon, 2019-12-02 at 11:58 -0800, Jacob Pan wrote:
> > Use combined macros for_each_svm_dev() to simplify SVM device
> > iteration and error checking.
> []
> > diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
> []
> > @@ -427,40 +430,36 @@ int intel_svm_unbind_mm(struct device *dev,
> > int pasid)
> []
> > + for_each_svm_dev(sdev, svm, dev) {
> > + ret = 0;
> > + sdev->users--;
> > + if (!sdev->users) {
>
> This might be better by reducing indentation here too
>
> if (sdev->users)
> break;
>
> > + list_del_rcu(>list);
>
> to reduce indentation 1 level below this
Sounds good but perhaps we can do this in a separate patch.
>
> > + /* 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);
> > + kfree_rcu(sdev, rcu);
> > +
> > + if (list_empty(>devs)) {
> > + ioasid_free(svm->pasid);
> > + if (svm->mm)
> > +
> > mmu_notifier_unregister(>notifier, svm->mm);
> > + list_del(>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(_mutex);
>
[Jacob Pan]
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Re: [PATCH v5 8/8] iommu/vt-d: Misc macro clean up for SVM
On Mon, 2019-12-02 at 11:58 -0800, Jacob Pan wrote:
> Use combined macros for_each_svm_dev() to simplify SVM device iteration
> and error checking.
[]
> diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
[]
> @@ -427,40 +430,36 @@ int intel_svm_unbind_mm(struct device *dev, int pasid)
[]
> + for_each_svm_dev(sdev, svm, dev) {
> + ret = 0;
> + sdev->users--;
> + if (!sdev->users) {
This might be better by reducing indentation here too
if (sdev->users)
break;
> + list_del_rcu(>list);
to reduce indentation 1 level below this
> + /* 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);
> + kfree_rcu(sdev, rcu);
> +
> + if (list_empty(>devs)) {
> + ioasid_free(svm->pasid);
> + if (svm->mm)
> + mmu_notifier_unregister(>notifier,
> svm->mm);
> + list_del(>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(_mutex);
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[PATCH v5 8/8] iommu/vt-d: Misc macro clean up for SVM
Use combined macros for_each_svm_dev() to simplify SVM device iteration
and error checking.
Suggested-by: Andy Shevchenko
Signed-off-by: Jacob Pan
Reviewed-by: Eric Auger
Acked-by: Lu Baolu
---
drivers/iommu/intel-svm.c | 79 +++
1 file changed, 39 insertions(+), 40 deletions(-)
diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 4ed7426473c1..0fcbe631cd5f 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -226,6 +226,10 @@ static const struct mmu_notifier_ops intel_mmuops = {
static DEFINE_MUTEX(pasid_mutex);
static LIST_HEAD(global_svm_list);
+#define for_each_svm_dev(sdev, svm, d) \
+ list_for_each_entry((sdev), &(svm)->devs, list) \
+ if ((d) != (sdev)->dev) {} else
+
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);
@@ -274,15 +278,14 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int
flags, struct svm_dev_
goto out;
}
- list_for_each_entry(sdev, >devs, list) {
- if (dev == sdev->dev) {
- if (sdev->ops != ops) {
- ret = -EBUSY;
- goto out;
- }
- sdev->users++;
- goto success;
+ /* Find the matching device in svm list */
+ for_each_svm_dev(sdev, svm, dev) {
+ if (sdev->ops != ops) {
+ ret = -EBUSY;
+ goto out;
}
+ sdev->users++;
+ goto success;
}
break;
@@ -427,40 +430,36 @@ int intel_svm_unbind_mm(struct device *dev, int pasid)
goto out;
}
- list_for_each_entry(sdev, >devs, list) {
- if (dev == sdev->dev) {
- ret = 0;
- sdev->users--;
- if (!sdev->users) {
- list_del_rcu(>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);
- kfree_rcu(sdev, rcu);
-
- if (list_empty(>devs)) {
- ioasid_free(svm->pasid);
- if (svm->mm)
-
mmu_notifier_unregister(>notifier, svm->mm);
-
- list_del(>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);
- }
+ for_each_svm_dev(sdev, svm, dev) {
+ ret = 0;
+ sdev->users--;
+ if (!sdev->users) {
+ list_del_rcu(>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);
+
