From: Alexander Ofitserov oficerovas@altlinux.org

From: Paolo Bonzini pbonzini@redhat.com

commit a8749a35c399 ("mm: vmalloc: introduce array allocation functions")

Linux has dozens of occurrences of vmalloc(array_size()) and vzalloc(array_size()). Allow to simplify the code by providing vmalloc_array and vcalloc, as well as the underscored variants that let the caller specify the GFP flags.

Acked-by: Michal Hocko mhocko@suse.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Alexander Ofitserov oficerovas@altlinux.org --- include/linux/vmalloc.h | 5 +++++ mm/util.c | 50 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 55 insertions(+)

diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 76dad53a410ac..0fd47f2f39eb0 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -112,6 +112,11 @@ extern void *__vmalloc_node_range(unsigned long size, unsigned long align, void *__vmalloc_node(unsigned long size, unsigned long align, gfp_t gfp_mask, int node, const void *caller);

+extern void *__vmalloc_array(size_t n, size_t size, gfp_t flags); +extern void *vmalloc_array(size_t n, size_t size); +extern void *__vcalloc(size_t n, size_t size, gfp_t flags); +extern void *vcalloc(size_t n, size_t size); + extern void vfree(const void *addr); extern void vfree_atomic(const void *addr);

diff --git a/mm/util.c b/mm/util.c index 25bfda774f6fd..7fd3c2bb3e4f5 100644 --- a/mm/util.c +++ b/mm/util.c @@ -686,6 +686,56 @@ static inline void *__page_rmapping(struct page *page) return (void *)mapping; }

+/** + * __vmalloc_array - allocate memory for a virtually contiguous array. + * @n: number of elements. + * @size: element size. + * @flags: the type of memory to allocate (see kmalloc). + */ +void *__vmalloc_array(size_t n, size_t size, gfp_t flags) +{ + size_t bytes; + + if (unlikely(check_mul_overflow(n, size, &bytes))) + return NULL; + return __vmalloc(bytes, flags); +} +EXPORT_SYMBOL(__vmalloc_array); + +/** + * vmalloc_array - allocate memory for a virtually contiguous array. + * @n: number of elements. + * @size: element size. + */ +void *vmalloc_array(size_t n, size_t size) +{ + return __vmalloc_array(n, size, GFP_KERNEL); +} +EXPORT_SYMBOL(vmalloc_array); + +/** + * __vcalloc - allocate and zero memory for a virtually contiguous array. + * @n: number of elements. + * @size: element size. + * @flags: the type of memory to allocate (see kmalloc). + */ +void *__vcalloc(size_t n, size_t size, gfp_t flags) +{ + return __vmalloc_array(n, size, flags | __GFP_ZERO); +} +EXPORT_SYMBOL(__vcalloc); + +/** + * vcalloc - allocate and zero memory for a virtually contiguous array. + * @n: number of elements. + * @size: element size. + */ +void *vcalloc(size_t n, size_t size) +{ + return __vmalloc_array(n, size, GFP_KERNEL | __GFP_ZERO); +} +EXPORT_SYMBOL(vcalloc); + /* Neutral page->mapping pointer to address_space or anon_vma or other */ void *page_rmapping(struct page *page) {

From: Alexander Ofitserov oficerovas@altlinux.org

From: Paolo Bonzini pbonzini@redhat.com

commit 37b2a6510a48 ("KVM: use __vcalloc for very large allocations")

Allocations whose size is related to the memslot size can be arbitrarily large. Do not use kvzalloc/kvcalloc, as those are limited to "not crazy" sizes that fit in 32 bits.

URL: https://lore.kernel.org/lkml/20220711090606.962822924@linuxfoundation.org/ Reviewed-by: David Hildenbrand david@redhat.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Alexander Ofitserov oficerovas@altlinux.org --- arch/powerpc/kvm/book3s_hv_uvmem.c | 2 +- arch/x86/kvm/mmu/page_track.c | 2 +- arch/x86/kvm/x86.c | 4 ++-- virt/kvm/kvm_main.c | 4 ++-- 4 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c index 3dd58b4ee33e5..5f6b3f80023de 100644 --- a/arch/powerpc/kvm/book3s_hv_uvmem.c +++ b/arch/powerpc/kvm/book3s_hv_uvmem.c @@ -250,7 +250,7 @@ int kvmppc_uvmem_slot_init(struct kvm *kvm, const struct kvm_memory_slot *slot) p = kzalloc(sizeof(*p), GFP_KERNEL); if (!p) return -ENOMEM; - p->pfns = vzalloc(array_size(slot->npages, sizeof(*p->pfns))); + p->pfns = vcalloc(slot->npages, sizeof(*p->pfns)); if (!p->pfns) { kfree(p); return -ENOMEM; diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c index 81cf4babbd0b4..3c379335ea477 100644 --- a/arch/x86/kvm/mmu/page_track.c +++ b/arch/x86/kvm/mmu/page_track.c @@ -35,7 +35,7 @@ int kvm_page_track_create_memslot(struct kvm_memory_slot *slot,

for (i = 0; i < KVM_PAGE_TRACK_MAX; i++) { slot->arch.gfn_track[i] = - kvcalloc(npages, sizeof(*slot->arch.gfn_track[i]), + __vcalloc(npages, sizeof(*slot->arch.gfn_track[i]), GFP_KERNEL_ACCOUNT); if (!slot->arch.gfn_track[i]) goto track_free; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 13e4699a0744f..6c2bf7cd7aec6 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10826,14 +10826,14 @@ static int kvm_alloc_memslot_metadata(struct kvm_memory_slot *slot, slot->base_gfn, level) + 1;

slot->arch.rmap[i] = - kvcalloc(lpages, sizeof(*slot->arch.rmap[i]), + __vcalloc(lpages, sizeof(*slot->arch.rmap[i]), GFP_KERNEL_ACCOUNT); if (!slot->arch.rmap[i]) goto out_free; if (i == 0) continue;

- linfo = kvcalloc(lpages, sizeof(*linfo), GFP_KERNEL_ACCOUNT); + linfo = __vcalloc(lpages, sizeof(*linfo), GFP_KERNEL_ACCOUNT); if (!linfo) goto out_free;

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 356fd5d1a4285..b7638c3c9eb7d 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1008,9 +1008,9 @@ static int kvm_vm_release(struct inode *inode, struct file *filp) */ static int kvm_alloc_dirty_bitmap(struct kvm_memory_slot *memslot) { - unsigned long dirty_bytes = 2 * kvm_dirty_bitmap_bytes(memslot); + unsigned long dirty_bytes = kvm_dirty_bitmap_bytes(memslot);

- memslot->dirty_bitmap = kvzalloc(dirty_bytes, GFP_KERNEL_ACCOUNT); + memslot->dirty_bitmap = __vcalloc(2, dirty_bytes, GFP_KERNEL_ACCOUNT); if (!memslot->dirty_bitmap) return -ENOMEM;