| Message ID | 1409575968-5329-3-git-send-email-eric.auger@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Sep 01, 2014 at 02:52:41PM +0200, Eric Auger wrote: > add a lock related to the rb tree manipulation. The rb tree can be Ok, I can't hold myself back any longer. Please begin sentences with a capital letter. You don't do this in French? :) > searched in one thread (irqfd handler for instance) and map/unmap > happen in another. > > Signed-off-by: Eric Auger <eric.auger@linaro.org> > --- > include/kvm/arm_vgic.h | 1 + > virt/kvm/arm/vgic.c | 46 +++++++++++++++++++++++++++++++++++++--------- > 2 files changed, 38 insertions(+), 9 deletions(-) > > diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h > index 743020f..3da244f 100644 > --- a/include/kvm/arm_vgic.h > +++ b/include/kvm/arm_vgic.h > @@ -177,6 +177,7 @@ struct vgic_dist { > unsigned long irq_pending_on_cpu; > > struct rb_root irq_phys_map; > + spinlock_t rb_tree_lock; > #endif > }; > > diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c > index 8ef495b..dbc2a5a 100644 > --- a/virt/kvm/arm/vgic.c > +++ b/virt/kvm/arm/vgic.c > @@ -1630,9 +1630,15 @@ static struct rb_root *vgic_get_irq_phys_map(struct kvm_vcpu *vcpu, > > int vgic_map_phys_irq(struct kvm_vcpu *vcpu, int virt_irq, int phys_irq) > { > - struct rb_root *root = vgic_get_irq_phys_map(vcpu, virt_irq); > - struct rb_node **new = &root->rb_node, *parent = NULL; > + struct rb_root *root; > + struct rb_node **new, *parent = NULL; > struct irq_phys_map *new_map; > + struct vgic_dist *dist = &vcpu->kvm->arch.vgic; > + > + spin_lock(&dist->rb_tree_lock); > + > + root = vgic_get_irq_phys_map(vcpu, virt_irq); > + new = &root->rb_node; > > /* Boilerplate rb_tree code */ > while (*new) { > @@ -1644,13 +1650,17 @@ int vgic_map_phys_irq(struct kvm_vcpu *vcpu, int virt_irq, int phys_irq) > new = &(*new)->rb_left; > else if (this->virt_irq > virt_irq) > new = &(*new)->rb_right; > - else > + else { > + spin_unlock(&dist->rb_tree_lock); > return -EEXIST; > + } can you initialize a ret variable to -EEXIST in the beginning of this function, and add an out label above the unlock below, replace this multi-line statement with a goto out, and set ret = 0 after the while loop? > } > > new_map = kzalloc(sizeof(*new_map), GFP_KERNEL); > - if (!new_map) > + if (!new_map) { > + spin_unlock(&dist->rb_tree_lock); > return -ENOMEM; then this becomes ret = -ENOMEM; goto out; > + } > > new_map->virt_irq = virt_irq; > new_map->phys_irq = phys_irq; > @@ -1658,6 +1668,8 @@ int vgic_map_phys_irq(struct kvm_vcpu *vcpu, int virt_irq, int phys_irq) > rb_link_node(&new_map->node, parent, new); > rb_insert_color(&new_map->node, root); > > + spin_unlock(&dist->rb_tree_lock); > + aren't you allocating memory with GFP_KERNEL while holding a spinlock here? > return 0; > } > > @@ -1685,24 +1697,39 @@ static struct irq_phys_map *vgic_irq_map_search(struct kvm_vcpu *vcpu, > > int vgic_get_phys_irq(struct kvm_vcpu *vcpu, int virt_irq) > { > - struct irq_phys_map *map = vgic_irq_map_search(vcpu, virt_irq); > + struct irq_phys_map *map; > + struct vgic_dist *dist = &vcpu->kvm->arch.vgic; > + int ret; > + > + spin_lock(&dist->rb_tree_lock); > + map = vgic_irq_map_search(vcpu, virt_irq); > > if (map) > - return map->phys_irq; > + ret = map->phys_irq; > + else > + ret = -ENOENT; initialize ret to -ENOENT and avoid the else statement. > + > + spin_unlock(&dist->rb_tree_lock); > + return ret; > > - return -ENOENT; > } > > int vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, int virt_irq, int phys_irq) > { > - struct irq_phys_map *map = vgic_irq_map_search(vcpu, virt_irq); > + struct irq_phys_map *map; > + struct vgic_dist *dist = &vcpu->kvm->arch.vgic; > + > + spin_lock(&dist->rb_tree_lock); > + > + map = vgic_irq_map_search(vcpu, virt_irq); > > if (map && map->phys_irq == phys_irq) { > rb_erase(&map->node, vgic_get_irq_phys_map(vcpu, virt_irq)); > kfree(map); > + spin_unlock(&dist->rb_tree_lock); can kfree sleep? I don't remember. In any case, you can unlock before calling kfree. > return 0; > } > - > + spin_unlock(&dist->rb_tree_lock); > return -ENOENT; an out label and single unlock location would be preferred here as well I think. > } > > @@ -1898,6 +1925,7 @@ int kvm_vgic_create(struct kvm *kvm) > } > > spin_lock_init(&kvm->arch.vgic.lock); > + spin_lock_init(&kvm->arch.vgic.rb_tree_lock); > kvm->arch.vgic.in_kernel = true; > kvm->arch.vgic.vctrl_base = vgic->vctrl_base; > kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF; > -- > 1.9.1 >
On 09/11/2014 05:09 AM, Christoffer Dall wrote: > On Mon, Sep 01, 2014 at 02:52:41PM +0200, Eric Auger wrote: >> add a lock related to the rb tree manipulation. The rb tree can be > > Ok, I can't hold myself back any longer. Please begin sentences with a > capital letter. You don't do this in French? :) Hi Christoffer, yep that's understood ;-) Definitively we do. Just that I am discovering it is common too in commits and comments ;-) > >> searched in one thread (irqfd handler for instance) and map/unmap >> happen in another. >> >> Signed-off-by: Eric Auger <eric.auger@linaro.org> >> --- >> include/kvm/arm_vgic.h | 1 + >> virt/kvm/arm/vgic.c | 46 +++++++++++++++++++++++++++++++++++++--------- >> 2 files changed, 38 insertions(+), 9 deletions(-) >> >> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h >> index 743020f..3da244f 100644 >> --- a/include/kvm/arm_vgic.h >> +++ b/include/kvm/arm_vgic.h >> @@ -177,6 +177,7 @@ struct vgic_dist { >> unsigned long irq_pending_on_cpu; >> >> struct rb_root irq_phys_map; >> + spinlock_t rb_tree_lock; >> #endif >> }; >> >> diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c >> index 8ef495b..dbc2a5a 100644 >> --- a/virt/kvm/arm/vgic.c >> +++ b/virt/kvm/arm/vgic.c >> @@ -1630,9 +1630,15 @@ static struct rb_root *vgic_get_irq_phys_map(struct kvm_vcpu *vcpu, >> >> int vgic_map_phys_irq(struct kvm_vcpu *vcpu, int virt_irq, int phys_irq) >> { >> - struct rb_root *root = vgic_get_irq_phys_map(vcpu, virt_irq); >> - struct rb_node **new = &root->rb_node, *parent = NULL; >> + struct rb_root *root; >> + struct rb_node **new, *parent = NULL; >> struct irq_phys_map *new_map; >> + struct vgic_dist *dist = &vcpu->kvm->arch.vgic; >> + >> + spin_lock(&dist->rb_tree_lock); >> + >> + root = vgic_get_irq_phys_map(vcpu, virt_irq); >> + new = &root->rb_node; >> >> /* Boilerplate rb_tree code */ >> while (*new) { >> @@ -1644,13 +1650,17 @@ int vgic_map_phys_irq(struct kvm_vcpu *vcpu, int virt_irq, int phys_irq) >> new = &(*new)->rb_left; >> else if (this->virt_irq > virt_irq) >> new = &(*new)->rb_right; >> - else >> + else { >> + spin_unlock(&dist->rb_tree_lock); >> return -EEXIST; >> + } > > can you initialize a ret variable to -EEXIST in the beginning of this > function, and add an out label above the unlock below, replace this > multi-line statement with a goto out, and set ret = 0 after the while > loop? sure > >> } >> >> new_map = kzalloc(sizeof(*new_map), GFP_KERNEL); >> - if (!new_map) >> + if (!new_map) { >> + spin_unlock(&dist->rb_tree_lock); >> return -ENOMEM; > > then this becomes ret = -ENOMEM; goto out; OK > >> + } >> >> new_map->virt_irq = virt_irq; >> new_map->phys_irq = phys_irq; >> @@ -1658,6 +1668,8 @@ int vgic_map_phys_irq(struct kvm_vcpu *vcpu, int virt_irq, int phys_irq) >> rb_link_node(&new_map->node, parent, new); >> rb_insert_color(&new_map->node, root); >> >> + spin_unlock(&dist->rb_tree_lock); >> + > > aren't you allocating memory with GFP_KERNEL while holding a spinlock > here? oups. Thanks for noticing. I Will move the lock. > >> return 0; >> } >> >> @@ -1685,24 +1697,39 @@ static struct irq_phys_map *vgic_irq_map_search(struct kvm_vcpu *vcpu, >> >> int vgic_get_phys_irq(struct kvm_vcpu *vcpu, int virt_irq) >> { >> - struct irq_phys_map *map = vgic_irq_map_search(vcpu, virt_irq); >> + struct irq_phys_map *map; >> + struct vgic_dist *dist = &vcpu->kvm->arch.vgic; >> + int ret; >> + >> + spin_lock(&dist->rb_tree_lock); >> + map = vgic_irq_map_search(vcpu, virt_irq); >> >> if (map) >> - return map->phys_irq; >> + ret = map->phys_irq; >> + else >> + ret = -ENOENT; > > initialize ret to -ENOENT and avoid the else statement. ok > >> + >> + spin_unlock(&dist->rb_tree_lock); >> + return ret; >> >> - return -ENOENT; >> } >> >> int vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, int virt_irq, int phys_irq) >> { >> - struct irq_phys_map *map = vgic_irq_map_search(vcpu, virt_irq); >> + struct irq_phys_map *map; >> + struct vgic_dist *dist = &vcpu->kvm->arch.vgic; >> + >> + spin_lock(&dist->rb_tree_lock); >> + >> + map = vgic_irq_map_search(vcpu, virt_irq); >> >> if (map && map->phys_irq == phys_irq) { >> rb_erase(&map->node, vgic_get_irq_phys_map(vcpu, virt_irq)); >> kfree(map); >> + spin_unlock(&dist->rb_tree_lock); > > can kfree sleep? I don't remember. In any case, you can unlock before > calling kfree. no it can't but I will move anyway. > >> return 0; >> } >> - >> + spin_unlock(&dist->rb_tree_lock); >> return -ENOENT; > > an out label and single unlock location would be preferred here as well > I think. ok Thansk Eric > >> } >> >> @@ -1898,6 +1925,7 @@ int kvm_vgic_create(struct kvm *kvm) >> } >> >> spin_lock_init(&kvm->arch.vgic.lock); >> + spin_lock_init(&kvm->arch.vgic.rb_tree_lock); >> kvm->arch.vgic.in_kernel = true; >> kvm->arch.vgic.vctrl_base = vgic->vctrl_base; >> kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF; >> -- >> 1.9.1 >>
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h index 743020f..3da244f 100644 --- a/include/kvm/arm_vgic.h +++ b/include/kvm/arm_vgic.h @@ -177,6 +177,7 @@ struct vgic_dist { unsigned long irq_pending_on_cpu; struct rb_root irq_phys_map; + spinlock_t rb_tree_lock; #endif }; diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c index 8ef495b..dbc2a5a 100644 --- a/virt/kvm/arm/vgic.c +++ b/virt/kvm/arm/vgic.c @@ -1630,9 +1630,15 @@ static struct rb_root *vgic_get_irq_phys_map(struct kvm_vcpu *vcpu, int vgic_map_phys_irq(struct kvm_vcpu *vcpu, int virt_irq, int phys_irq) { - struct rb_root *root = vgic_get_irq_phys_map(vcpu, virt_irq); - struct rb_node **new = &root->rb_node, *parent = NULL; + struct rb_root *root; + struct rb_node **new, *parent = NULL; struct irq_phys_map *new_map; + struct vgic_dist *dist = &vcpu->kvm->arch.vgic; + + spin_lock(&dist->rb_tree_lock); + + root = vgic_get_irq_phys_map(vcpu, virt_irq); + new = &root->rb_node; /* Boilerplate rb_tree code */ while (*new) { @@ -1644,13 +1650,17 @@ int vgic_map_phys_irq(struct kvm_vcpu *vcpu, int virt_irq, int phys_irq) new = &(*new)->rb_left; else if (this->virt_irq > virt_irq) new = &(*new)->rb_right; - else + else { + spin_unlock(&dist->rb_tree_lock); return -EEXIST; + } } new_map = kzalloc(sizeof(*new_map), GFP_KERNEL); - if (!new_map) + if (!new_map) { + spin_unlock(&dist->rb_tree_lock); return -ENOMEM; + } new_map->virt_irq = virt_irq; new_map->phys_irq = phys_irq; @@ -1658,6 +1668,8 @@ int vgic_map_phys_irq(struct kvm_vcpu *vcpu, int virt_irq, int phys_irq) rb_link_node(&new_map->node, parent, new); rb_insert_color(&new_map->node, root); + spin_unlock(&dist->rb_tree_lock); + return 0; } @@ -1685,24 +1697,39 @@ static struct irq_phys_map *vgic_irq_map_search(struct kvm_vcpu *vcpu, int vgic_get_phys_irq(struct kvm_vcpu *vcpu, int virt_irq) { - struct irq_phys_map *map = vgic_irq_map_search(vcpu, virt_irq); + struct irq_phys_map *map; + struct vgic_dist *dist = &vcpu->kvm->arch.vgic; + int ret; + + spin_lock(&dist->rb_tree_lock); + map = vgic_irq_map_search(vcpu, virt_irq); if (map) - return map->phys_irq; + ret = map->phys_irq; + else + ret = -ENOENT; + + spin_unlock(&dist->rb_tree_lock); + return ret; - return -ENOENT; } int vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, int virt_irq, int phys_irq) { - struct irq_phys_map *map = vgic_irq_map_search(vcpu, virt_irq); + struct irq_phys_map *map; + struct vgic_dist *dist = &vcpu->kvm->arch.vgic; + + spin_lock(&dist->rb_tree_lock); + + map = vgic_irq_map_search(vcpu, virt_irq); if (map && map->phys_irq == phys_irq) { rb_erase(&map->node, vgic_get_irq_phys_map(vcpu, virt_irq)); kfree(map); + spin_unlock(&dist->rb_tree_lock); return 0; } - + spin_unlock(&dist->rb_tree_lock); return -ENOENT; } @@ -1898,6 +1925,7 @@ int kvm_vgic_create(struct kvm *kvm) } spin_lock_init(&kvm->arch.vgic.lock); + spin_lock_init(&kvm->arch.vgic.rb_tree_lock); kvm->arch.vgic.in_kernel = true; kvm->arch.vgic.vctrl_base = vgic->vctrl_base; kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
add a lock related to the rb tree manipulation. The rb tree can be searched in one thread (irqfd handler for instance) and map/unmap happen in another. Signed-off-by: Eric Auger <eric.auger@linaro.org> --- include/kvm/arm_vgic.h | 1 + virt/kvm/arm/vgic.c | 46 +++++++++++++++++++++++++++++++++++++--------- 2 files changed, 38 insertions(+), 9 deletions(-)