| Message ID | 20210918142138.17709-1-len.baker@gmx.com |
|---|---|
| State | New |
| Headers | show |
| Series | KVM: PPC: Replace zero-length array with flexible array member | expand |
On 9/18/21 09:21, Len Baker wrote: > There is a regular need in the kernel to provide a way to declare having > a dynamically sized set of trailing elements in a structure. Kernel code > should always use "flexible array members" [1] for these cases. The > older style of one-element or zero-length arrays should no longer be > used[2]. > > Also, make use of the struct_size() helper in kzalloc(). > > [1] https://en.wikipedia.org/wiki/Flexible_array_member > [2] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays > > Signed-off-by: Len Baker <len.baker@gmx.com> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> Thanks -- Gustavo > --- > arch/powerpc/include/asm/kvm_host.h | 2 +- > arch/powerpc/kvm/book3s_64_vio.c | 3 +-- > 2 files changed, 2 insertions(+), 3 deletions(-) > > diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h > index 080a7feb7731..3aed653373a5 100644 > --- a/arch/powerpc/include/asm/kvm_host.h > +++ b/arch/powerpc/include/asm/kvm_host.h > @@ -190,7 +190,7 @@ struct kvmppc_spapr_tce_table { > u64 size; /* window size in pages */ > struct list_head iommu_tables; > struct mutex alloc_lock; > - struct page *pages[0]; > + struct page *pages[]; > }; > > /* XICS components, defined in book3s_xics.c */ > diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c > index 6365087f3160..d42b4b6d4a79 100644 > --- a/arch/powerpc/kvm/book3s_64_vio.c > +++ b/arch/powerpc/kvm/book3s_64_vio.c > @@ -295,8 +295,7 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm, > return ret; > > ret = -ENOMEM; > - stt = kzalloc(sizeof(*stt) + npages * sizeof(struct page *), > - GFP_KERNEL); > + stt = kzalloc(struct_size(stt, pages, npages), GFP_KERNEL); > if (!stt) > goto fail_acct; > > -- > 2.25.1 >
On Mon, Sep 20, 2021 at 07:05:07PM -0500, Gustavo A. R. Silva wrote: > > > On 9/18/21 09:21, Len Baker wrote: > > There is a regular need in the kernel to provide a way to declare having > > a dynamically sized set of trailing elements in a structure. Kernel code > > should always use "flexible array members" [1] for these cases. The > > older style of one-element or zero-length arrays should no longer be > > used[2]. > > > > Also, make use of the struct_size() helper in kzalloc(). > > > > [1] https://en.wikipedia.org/wiki/Flexible_array_member > > [2] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays > > > > Signed-off-by: Len Baker <len.baker@gmx.com> > > Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> I'm taking this in my -next tree. Thanks -- Gustavo
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h index 080a7feb7731..3aed653373a5 100644 --- a/arch/powerpc/include/asm/kvm_host.h +++ b/arch/powerpc/include/asm/kvm_host.h @@ -190,7 +190,7 @@ struct kvmppc_spapr_tce_table { u64 size; /* window size in pages */ struct list_head iommu_tables; struct mutex alloc_lock; - struct page *pages[0]; + struct page *pages[]; }; /* XICS components, defined in book3s_xics.c */ diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c index 6365087f3160..d42b4b6d4a79 100644 --- a/arch/powerpc/kvm/book3s_64_vio.c +++ b/arch/powerpc/kvm/book3s_64_vio.c @@ -295,8 +295,7 @@ long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm, return ret; ret = -ENOMEM; - stt = kzalloc(sizeof(*stt) + npages * sizeof(struct page *), - GFP_KERNEL); + stt = kzalloc(struct_size(stt, pages, npages), GFP_KERNEL); if (!stt) goto fail_acct;
There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use "flexible array members" [1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. Also, make use of the struct_size() helper in kzalloc(). [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays Signed-off-by: Len Baker <len.baker@gmx.com> --- arch/powerpc/include/asm/kvm_host.h | 2 +- arch/powerpc/kvm/book3s_64_vio.c | 3 +-- 2 files changed, 2 insertions(+), 3 deletions(-) -- 2.25.1