| Message ID | 20190531192453.GA13536@embeddedor (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: irqchip: Use struct_size() in kzalloc() | expand |
On 31/05/19 21:24, Gustavo A. R. Silva wrote: > One of the more common cases of allocation size calculations is finding > the size of a structure that has a zero-sized array at the end, along > with memory for some number of elements for that array. For example: > > struct foo { > int stuff; > struct boo entry[]; > }; > > instance = kzalloc(sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL); > > Instead of leaving these open-coded and prone to type mistakes, we can > now use the new struct_size() helper: > > instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL); > > This code was detected with the help of Coccinelle. > > Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> > --- > virt/kvm/irqchip.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c > index 79e59e4fa3dc..f8be6a3d1aa6 100644 > --- a/virt/kvm/irqchip.c > +++ b/virt/kvm/irqchip.c > @@ -196,9 +196,7 @@ int kvm_set_irq_routing(struct kvm *kvm, > > nr_rt_entries += 1; > > - new = kzalloc(sizeof(*new) + (nr_rt_entries * sizeof(struct hlist_head)), > - GFP_KERNEL_ACCOUNT); > - > + new = kzalloc(struct_size(new, map, nr_rt_entries), GFP_KERNEL_ACCOUNT); > if (!new) > return -ENOMEM; > > Queued, thanks. Paolo
On 6/4/19 12:20 PM, Paolo Bonzini wrote: > > Queued, thanks. > Great. :) Thanks, Paolo. -- Gustavo
diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c index 79e59e4fa3dc..f8be6a3d1aa6 100644 --- a/virt/kvm/irqchip.c +++ b/virt/kvm/irqchip.c @@ -196,9 +196,7 @@ int kvm_set_irq_routing(struct kvm *kvm, nr_rt_entries += 1; - new = kzalloc(sizeof(*new) + (nr_rt_entries * sizeof(struct hlist_head)), - GFP_KERNEL_ACCOUNT); - + new = kzalloc(struct_size(new, map, nr_rt_entries), GFP_KERNEL_ACCOUNT); if (!new) return -ENOMEM;
One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct foo { int stuff; struct boo entry[]; }; instance = kzalloc(sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL); This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> --- virt/kvm/irqchip.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)