| Message ID | 1470671271-22465-1-git-send-email-keith.busch@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
Seems fine and didn't grow the struct, which is always nice Acked-by Jon Derrick: <jonathan.derrick@intel.com> On Mon, Aug 08, 2016 at 09:47:51AM -0600, Keith Busch wrote: > We can't initialize the list head on deletion as this causes the node > to point to itself, looping infinitely if the vmd IRQ handler happened > to be servicing that node. > > The list initialization was trying fix a bug from multiple calls to > disable the same IRQ. We can fix this instead by having the vmd driver > track if the interrupt is enabled. > > Signed-off-by: Keith Busch <keith.busch@intel.com> > Cc: Jon Derrick <jonathan.derrick@intel.com> > Reported-by: Grzegorz Koczot <grzegorz.koczot@intel.com> > Tested-by: Miroslaw Drost <miroslaw.drost@intel.com> > --- > v1 -> v2: > > Removed check for poisioned list pointer. This is abusing knowledge > internal to the list api, so we need another way to know if the child > irq is enabled. This patch uses a driver controlled boolean for this. > > Added tags for the bug reporter and tester. > > arch/x86/pci/vmd.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/pci/vmd.c b/arch/x86/pci/vmd.c > index e88b417..4b85837 100644 > --- a/arch/x86/pci/vmd.c > +++ b/arch/x86/pci/vmd.c > @@ -41,6 +41,7 @@ static DEFINE_RAW_SPINLOCK(list_lock); > * @node: list item for parent traversal. > * @rcu: RCU callback item for freeing. > * @irq: back pointer to parent. > + * @enabled: true if driver enabled irq > * @virq: the virtual IRQ value provided to the requesting driver. > * > * Every MSI/MSI-X IRQ requested for a device in a VMD domain will be mapped to > @@ -50,6 +51,7 @@ struct vmd_irq { > struct list_head node; > struct rcu_head rcu; > struct vmd_irq_list *irq; > + bool enabled; > unsigned int virq; > }; > > @@ -122,7 +124,9 @@ static void vmd_irq_enable(struct irq_data *data) > unsigned long flags; > > raw_spin_lock_irqsave(&list_lock, flags); > + WARN_ON(vmdirq->enabled); > list_add_tail_rcu(&vmdirq->node, &vmdirq->irq->irq_list); > + vmdirq->enabled = true; > raw_spin_unlock_irqrestore(&list_lock, flags); > > data->chip->irq_unmask(data); > @@ -136,8 +140,10 @@ static void vmd_irq_disable(struct irq_data *data) > data->chip->irq_mask(data); > > raw_spin_lock_irqsave(&list_lock, flags); > - list_del_rcu(&vmdirq->node); > - INIT_LIST_HEAD_RCU(&vmdirq->node); > + if (vmdirq->enabled) { > + list_del_rcu(&vmdirq->node); > + vmdirq->enabled = false; > + } > raw_spin_unlock_irqrestore(&list_lock, flags); > } > > -- > 2.7.2 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Keith, On Mon, Aug 08, 2016 at 09:47:51AM -0600, Keith Busch wrote: > We can't initialize the list head on deletion as this causes the node > to point to itself, looping infinitely if the vmd IRQ handler happened > to be servicing that node. > > The list initialization was trying fix a bug from multiple calls to > disable the same IRQ. We can fix this instead by having the vmd driver > track if the interrupt is enabled. > > Signed-off-by: Keith Busch <keith.busch@intel.com> > Cc: Jon Derrick <jonathan.derrick@intel.com> > Reported-by: Grzegorz Koczot <grzegorz.koczot@intel.com> > Tested-by: Miroslaw Drost <miroslaw.drost@intel.com> I assume you want Fixes: 97e923063575 ("x86/PCI: VMD: Initialize list item in IRQ disable") and you want this in for-linus so it goes in v4.8 instead of v4.9. I did that for you, so let me know if it's not right. > --- > v1 -> v2: > > Removed check for poisioned list pointer. This is abusing knowledge > internal to the list api, so we need another way to know if the child > irq is enabled. This patch uses a driver controlled boolean for this. > > Added tags for the bug reporter and tester. > > arch/x86/pci/vmd.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/pci/vmd.c b/arch/x86/pci/vmd.c > index e88b417..4b85837 100644 > --- a/arch/x86/pci/vmd.c > +++ b/arch/x86/pci/vmd.c > @@ -41,6 +41,7 @@ static DEFINE_RAW_SPINLOCK(list_lock); > * @node: list item for parent traversal. > * @rcu: RCU callback item for freeing. > * @irq: back pointer to parent. > + * @enabled: true if driver enabled irq > * @virq: the virtual IRQ value provided to the requesting driver. > * > * Every MSI/MSI-X IRQ requested for a device in a VMD domain will be mapped to > @@ -50,6 +51,7 @@ struct vmd_irq { > struct list_head node; > struct rcu_head rcu; > struct vmd_irq_list *irq; > + bool enabled; > unsigned int virq; > }; > > @@ -122,7 +124,9 @@ static void vmd_irq_enable(struct irq_data *data) > unsigned long flags; > > raw_spin_lock_irqsave(&list_lock, flags); > + WARN_ON(vmdirq->enabled); > list_add_tail_rcu(&vmdirq->node, &vmdirq->irq->irq_list); > + vmdirq->enabled = true; > raw_spin_unlock_irqrestore(&list_lock, flags); > > data->chip->irq_unmask(data); > @@ -136,8 +140,10 @@ static void vmd_irq_disable(struct irq_data *data) > data->chip->irq_mask(data); > > raw_spin_lock_irqsave(&list_lock, flags); > - list_del_rcu(&vmdirq->node); > - INIT_LIST_HEAD_RCU(&vmdirq->node); > + if (vmdirq->enabled) { > + list_del_rcu(&vmdirq->node); > + vmdirq->enabled = false; > + } > raw_spin_unlock_irqrestore(&list_lock, flags); > } > > -- > 2.7.2 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Aug 23, 2016 at 04:36:05PM -0500, Bjorn Helgaas wrote: > On Mon, Aug 08, 2016 at 09:47:51AM -0600, Keith Busch wrote: > > We can't initialize the list head on deletion as this causes the node > > to point to itself, looping infinitely if the vmd IRQ handler happened > > to be servicing that node. > > > > The list initialization was trying fix a bug from multiple calls to > > disable the same IRQ. We can fix this instead by having the vmd driver > > track if the interrupt is enabled. > > > > Signed-off-by: Keith Busch <keith.busch@intel.com> > > Cc: Jon Derrick <jonathan.derrick@intel.com> > > Reported-by: Grzegorz Koczot <grzegorz.koczot@intel.com> > > Tested-by: Miroslaw Drost <miroslaw.drost@intel.com> > > I assume you want > > Fixes: 97e923063575 ("x86/PCI: VMD: Initialize list item in IRQ disable") > > and you want this in for-linus so it goes in v4.8 instead of v4.9. > > I did that for you, so let me know if it's not right. Yes, that was our intention. Thank you for setting the "Fixes" and staging for 4.8. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/pci/vmd.c b/arch/x86/pci/vmd.c index e88b417..4b85837 100644 --- a/arch/x86/pci/vmd.c +++ b/arch/x86/pci/vmd.c @@ -41,6 +41,7 @@ static DEFINE_RAW_SPINLOCK(list_lock); * @node: list item for parent traversal. * @rcu: RCU callback item for freeing. * @irq: back pointer to parent. + * @enabled: true if driver enabled irq * @virq: the virtual IRQ value provided to the requesting driver. * * Every MSI/MSI-X IRQ requested for a device in a VMD domain will be mapped to @@ -50,6 +51,7 @@ struct vmd_irq { struct list_head node; struct rcu_head rcu; struct vmd_irq_list *irq; + bool enabled; unsigned int virq; }; @@ -122,7 +124,9 @@ static void vmd_irq_enable(struct irq_data *data) unsigned long flags; raw_spin_lock_irqsave(&list_lock, flags); + WARN_ON(vmdirq->enabled); list_add_tail_rcu(&vmdirq->node, &vmdirq->irq->irq_list); + vmdirq->enabled = true; raw_spin_unlock_irqrestore(&list_lock, flags); data->chip->irq_unmask(data); @@ -136,8 +140,10 @@ static void vmd_irq_disable(struct irq_data *data) data->chip->irq_mask(data); raw_spin_lock_irqsave(&list_lock, flags); - list_del_rcu(&vmdirq->node); - INIT_LIST_HEAD_RCU(&vmdirq->node); + if (vmdirq->enabled) { + list_del_rcu(&vmdirq->node); + vmdirq->enabled = false; + } raw_spin_unlock_irqrestore(&list_lock, flags); }