From: Paolo Bonzini <pbonzini@redhat.com>
Date: Tue, 8 Mar 2022 04:47:22 -0500
Subject: mm: vmalloc: introduce array allocation functions
Git-commit: a8749a35c39903120ec421ef2525acc8e0daa55c
Patch-mainline: v5.18-rc1
References: bsc#1198110

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>
Acked-by: Dario Faggioli <dfaggioli@suse.com>
---
 include/linux/vmalloc.h |  5 +++++
 mm/util.c               | 50 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)

--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -152,6 +152,11 @@
 		int node, const void *caller);
 void *vmalloc_no_huge(unsigned long size);
 
+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);
 
--- a/mm/util.c
+++ b/mm/util.c
@@ -664,6 +664,56 @@
 	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)
 {