linux-kernel - [PATCH 1/2] mm: vmalloc: introduce array allocation functions

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Message-ID: <20240126094023.2677376-2-oficerovas@altlinux.org>
Date: Fri, 26 Jan 2024 12:40:22 +0300
From: oficerovas@...linux.org
To: oficerovas@...linux.org,
	linux-kernel@...r.kernel.org,
	kvm@...r.kernel.org
Cc: kovalev@...linux.org
Subject: [PATCH 1/2] mm: vmalloc: introduce array allocation functions

From: Alexander Ofitserov <oficerovas@...linux.org>

From: Paolo Bonzini <pbonzini@...hat.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@...e.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Alexander Ofitserov <oficerovas@...linux.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)
 {
-- 
2.42.1