headers/deps: mm: Introduce <linux/highmem_extra.h> for rarely used APIs

Move various rarely used APIs to the new header, the main
<linux/highmem.h> header is included over 2,700 times
on a typical distro kernel build.

The new header is only used in ~130 .c files directly & indirectly.

The motivation is to reduce header dependencies of <linux/highmem.h>.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

3 files changed, 252 insertions, 245 deletions

diff --git a/include/linux/bvec_api.h b/include/linux/bvec_api.h
index 91bc70df0fd354..75699845a3ed28 100644
--- a/include/linux/bvec_api.h
+++ b/include/linux/bvec_api.h
@@ -9,6 +9,7 @@
 
 #include <linux/bvec_types.h>
 
+#include <linux/highmem_extra.h>
 #include <linux/highmem.h>
 
 /**
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index a6273310573cbc..6414a8c2959680 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -167,249 +167,4 @@ void *kmap_atomic(struct page *page);
  * preemption.
  */
 
-/* Highmem related interfaces for management code */
-static inline unsigned int nr_free_highpages(void);
-static inline unsigned long totalhigh_pages(void);
-
-#ifndef ARCH_HAS_FLUSH_ANON_PAGE
-static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
-{
-}
-#endif
-
-#ifndef ARCH_IMPLEMENTS_FLUSH_KERNEL_VMAP_RANGE
-static inline void flush_kernel_vmap_range(void *vaddr, int size)
-{
-}
-static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
-{
-}
-#endif
-
-/* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
-#ifndef clear_user_highpage
-static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
-{
-	void *addr = kmap_local_page(page);
-	clear_user_page(addr, vaddr, page);
-	kunmap_local(addr);
-}
-#endif
-
-#ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE_MOVABLE
-/**
- * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
- * @vma: The VMA the page is to be allocated for
- * @vaddr: The virtual address the page will be inserted into
- *
- * This function will allocate a page for a VMA that the caller knows will
- * be able to migrate in the future using move_pages() or reclaimed
- *
- * An architecture may override this function by defining
- * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE_MOVABLE and providing their own
- * implementation.
- */
-static inline struct page *
-alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
-				   unsigned long vaddr)
-{
-	struct page *page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vaddr);
-
-	if (page)
-		clear_user_highpage(page, vaddr);
-
-	return page;
-}
-#endif
-
-static inline void clear_highpage(struct page *page)
-{
-	void *kaddr = kmap_local_page(page);
-	clear_page(kaddr);
-	kunmap_local(kaddr);
-}
-
-#ifndef __HAVE_ARCH_TAG_CLEAR_HIGHPAGE
-
-static inline void tag_clear_highpage(struct page *page)
-{
-}
-
-#endif
-
-/*
- * If we pass in a base or tail page, we can zero up to PAGE_SIZE.
- * If we pass in a head page, we can zero up to the size of the compound page.
- */
-#ifdef CONFIG_HIGHMEM
-void zero_user_segments(struct page *page, unsigned start1, unsigned end1,
-		unsigned start2, unsigned end2);
-#else
-static inline void zero_user_segments(struct page *page,
-		unsigned start1, unsigned end1,
-		unsigned start2, unsigned end2)
-{
-	void *kaddr = kmap_local_page(page);
-	unsigned int i;
-
-	BUG_ON(end1 > page_size(page) || end2 > page_size(page));
-
-	if (end1 > start1)
-		memset(kaddr + start1, 0, end1 - start1);
-
-	if (end2 > start2)
-		memset(kaddr + start2, 0, end2 - start2);
-
-	kunmap_local(kaddr);
-	for (i = 0; i < compound_nr(page); i++)
-		flush_dcache_page(page + i);
-}
-#endif
-
-static inline void zero_user_segment(struct page *page,
-	unsigned start, unsigned end)
-{
-	zero_user_segments(page, start, end, 0, 0);
-}
-
-static inline void zero_user(struct page *page,
-	unsigned start, unsigned size)
-{
-	zero_user_segments(page, start, start + size, 0, 0);
-}
-
-#ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
-
-static inline void copy_user_highpage(struct page *to, struct page *from,
-	unsigned long vaddr, struct vm_area_struct *vma)
-{
-	char *vfrom, *vto;
-
-	vfrom = kmap_local_page(from);
-	vto = kmap_local_page(to);
-	copy_user_page(vto, vfrom, vaddr, to);
-	kunmap_local(vto);
-	kunmap_local(vfrom);
-}
-
-#endif
-
-#ifndef __HAVE_ARCH_COPY_HIGHPAGE
-
-static inline void copy_highpage(struct page *to, struct page *from)
-{
-	char *vfrom, *vto;
-
-	vfrom = kmap_local_page(from);
-	vto = kmap_local_page(to);
-	copy_page(vto, vfrom);
-	kunmap_local(vto);
-	kunmap_local(vfrom);
-}
-
-#endif
-
-static inline void memcpy_page(struct page *dst_page, size_t dst_off,
-			       struct page *src_page, size_t src_off,
-			       size_t len)
-{
-	char *dst = kmap_local_page(dst_page);
-	char *src = kmap_local_page(src_page);
-
-	VM_BUG_ON(dst_off + len > PAGE_SIZE || src_off + len > PAGE_SIZE);
-	memcpy(dst + dst_off, src + src_off, len);
-	kunmap_local(src);
-	kunmap_local(dst);
-}
-
-static inline void memmove_page(struct page *dst_page, size_t dst_off,
-			       struct page *src_page, size_t src_off,
-			       size_t len)
-{
-	char *dst = kmap_local_page(dst_page);
-	char *src = kmap_local_page(src_page);
-
-	VM_BUG_ON(dst_off + len > PAGE_SIZE || src_off + len > PAGE_SIZE);
-	memmove(dst + dst_off, src + src_off, len);
-	kunmap_local(src);
-	kunmap_local(dst);
-}
-
-static inline void memset_page(struct page *page, size_t offset, int val,
-			       size_t len)
-{
-	char *addr = kmap_local_page(page);
-
-	VM_BUG_ON(offset + len > PAGE_SIZE);
-	memset(addr + offset, val, len);
-	kunmap_local(addr);
-}
-
-static inline void memcpy_from_page(char *to, struct page *page,
-				    size_t offset, size_t len)
-{
-	char *from = kmap_local_page(page);
-
-	VM_BUG_ON(offset + len > PAGE_SIZE);
-	memcpy(to, from + offset, len);
-	kunmap_local(from);
-}
-
-static inline void memcpy_to_page(struct page *page, size_t offset,
-				  const char *from, size_t len)
-{
-	char *to = kmap_local_page(page);
-
-	VM_BUG_ON(offset + len > PAGE_SIZE);
-	memcpy(to + offset, from, len);
-	flush_dcache_page(page);
-	kunmap_local(to);
-}
-
-static inline void memzero_page(struct page *page, size_t offset, size_t len)
-{
-	char *addr = kmap_local_page(page);
-	memset(addr + offset, 0, len);
-	flush_dcache_page(page);
-	kunmap_local(addr);
-}
-
-/**
- * folio_zero_segments() - Zero two byte ranges in a folio.
- * @folio: The folio to write to.
- * @start1: The first byte to zero.
- * @xend1: One more than the last byte in the first range.
- * @start2: The first byte to zero in the second range.
- * @xend2: One more than the last byte in the second range.
- */
-static inline void folio_zero_segments(struct folio *folio,
-		size_t start1, size_t xend1, size_t start2, size_t xend2)
-{
-	zero_user_segments(&folio->page, start1, xend1, start2, xend2);
-}
-
-/**
- * folio_zero_segment() - Zero a byte range in a folio.
- * @folio: The folio to write to.
- * @start: The first byte to zero.
- * @xend: One more than the last byte to zero.
- */
-static inline void folio_zero_segment(struct folio *folio,
-		size_t start, size_t xend)
-{
-	zero_user_segments(&folio->page, start, xend, 0, 0);
-}
-
-/**
- * folio_zero_range() - Zero a byte range in a folio.
- * @folio: The folio to write to.
- * @start: The first byte to zero.
- * @length: The number of bytes to zero.
- */
-static inline void folio_zero_range(struct folio *folio,
-		size_t start, size_t length)
-{
-	zero_user_segments(&folio->page, start, start + length, 0, 0);
-}
-
 #endif /* _LINUX_HIGHMEM_H */
diff --git a/include/linux/highmem_extra.h b/include/linux/highmem_extra.h
index 9a515c9a213137..9b9e1d8059b553 100644
--- a/include/linux/highmem_extra.h
+++ b/include/linux/highmem_extra.h
@@ -1 +1,252 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_HIGHMEM_EXTRA_H
+#define _LINUX_HIGHMEM_EXTRA_H
+
 #include <linux/highmem.h>
+
+/* Highmem related interfaces for management code */
+static inline unsigned int nr_free_highpages(void);
+static inline unsigned long totalhigh_pages(void);
+
+#ifndef ARCH_HAS_FLUSH_ANON_PAGE
+static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
+{
+}
+#endif
+
+#ifndef ARCH_IMPLEMENTS_FLUSH_KERNEL_VMAP_RANGE
+static inline void flush_kernel_vmap_range(void *vaddr, int size)
+{
+}
+static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
+{
+}
+#endif
+
+/* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
+#ifndef clear_user_highpage
+static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
+{
+	void *addr = kmap_local_page(page);
+	clear_user_page(addr, vaddr, page);
+	kunmap_local(addr);
+}
+#endif
+
+#ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE_MOVABLE
+/**
+ * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
+ * @vma: The VMA the page is to be allocated for
+ * @vaddr: The virtual address the page will be inserted into
+ *
+ * This function will allocate a page for a VMA that the caller knows will
+ * be able to migrate in the future using move_pages() or reclaimed
+ *
+ * An architecture may override this function by defining
+ * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE_MOVABLE and providing their own
+ * implementation.
+ */
+static inline struct page *
+alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
+				   unsigned long vaddr)
+{
+	struct page *page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vaddr);
+
+	if (page)
+		clear_user_highpage(page, vaddr);
+
+	return page;
+}
+#endif
+
+static inline void clear_highpage(struct page *page)
+{
+	void *kaddr = kmap_local_page(page);
+	clear_page(kaddr);
+	kunmap_local(kaddr);
+}
+
+#ifndef __HAVE_ARCH_TAG_CLEAR_HIGHPAGE
+
+static inline void tag_clear_highpage(struct page *page)
+{
+}
+
+#endif
+
+/*
+ * If we pass in a base or tail page, we can zero up to PAGE_SIZE.
+ * If we pass in a head page, we can zero up to the size of the compound page.
+ */
+#ifdef CONFIG_HIGHMEM
+void zero_user_segments(struct page *page, unsigned start1, unsigned end1,
+		unsigned start2, unsigned end2);
+#else
+static inline void zero_user_segments(struct page *page,
+		unsigned start1, unsigned end1,
+		unsigned start2, unsigned end2)
+{
+	void *kaddr = kmap_local_page(page);
+	unsigned int i;
+
+	BUG_ON(end1 > page_size(page) || end2 > page_size(page));
+
+	if (end1 > start1)
+		memset(kaddr + start1, 0, end1 - start1);
+
+	if (end2 > start2)
+		memset(kaddr + start2, 0, end2 - start2);
+
+	kunmap_local(kaddr);
+	for (i = 0; i < compound_nr(page); i++)
+		flush_dcache_page(page + i);
+}
+#endif
+
+static inline void zero_user_segment(struct page *page,
+	unsigned start, unsigned end)
+{
+	zero_user_segments(page, start, end, 0, 0);
+}
+
+static inline void zero_user(struct page *page,
+	unsigned start, unsigned size)
+{
+	zero_user_segments(page, start, start + size, 0, 0);
+}
+
+#ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
+
+static inline void copy_user_highpage(struct page *to, struct page *from,
+	unsigned long vaddr, struct vm_area_struct *vma)
+{
+	char *vfrom, *vto;
+
+	vfrom = kmap_local_page(from);
+	vto = kmap_local_page(to);
+	copy_user_page(vto, vfrom, vaddr, to);
+	kunmap_local(vto);
+	kunmap_local(vfrom);
+}
+
+#endif
+
+#ifndef __HAVE_ARCH_COPY_HIGHPAGE
+
+static inline void copy_highpage(struct page *to, struct page *from)
+{
+	char *vfrom, *vto;
+
+	vfrom = kmap_local_page(from);
+	vto = kmap_local_page(to);
+	copy_page(vto, vfrom);
+	kunmap_local(vto);
+	kunmap_local(vfrom);
+}
+
+#endif
+
+static inline void memcpy_page(struct page *dst_page, size_t dst_off,
+			       struct page *src_page, size_t src_off,
+			       size_t len)
+{
+	char *dst = kmap_local_page(dst_page);
+	char *src = kmap_local_page(src_page);
+
+	VM_BUG_ON(dst_off + len > PAGE_SIZE || src_off + len > PAGE_SIZE);
+	memcpy(dst + dst_off, src + src_off, len);
+	kunmap_local(src);
+	kunmap_local(dst);
+}
+
+static inline void memmove_page(struct page *dst_page, size_t dst_off,
+			       struct page *src_page, size_t src_off,
+			       size_t len)
+{
+	char *dst = kmap_local_page(dst_page);
+	char *src = kmap_local_page(src_page);
+
+	VM_BUG_ON(dst_off + len > PAGE_SIZE || src_off + len > PAGE_SIZE);
+	memmove(dst + dst_off, src + src_off, len);
+	kunmap_local(src);
+	kunmap_local(dst);
+}
+
+static inline void memset_page(struct page *page, size_t offset, int val,
+			       size_t len)
+{
+	char *addr = kmap_local_page(page);
+
+	VM_BUG_ON(offset + len > PAGE_SIZE);
+	memset(addr + offset, val, len);
+	kunmap_local(addr);
+}
+
+static inline void memcpy_from_page(char *to, struct page *page,
+				    size_t offset, size_t len)
+{
+	char *from = kmap_local_page(page);
+
+	VM_BUG_ON(offset + len > PAGE_SIZE);
+	memcpy(to, from + offset, len);
+	kunmap_local(from);
+}
+
+static inline void memcpy_to_page(struct page *page, size_t offset,
+				  const char *from, size_t len)
+{
+	char *to = kmap_local_page(page);
+
+	VM_BUG_ON(offset + len > PAGE_SIZE);
+	memcpy(to + offset, from, len);
+	flush_dcache_page(page);
+	kunmap_local(to);
+}
+
+static inline void memzero_page(struct page *page, size_t offset, size_t len)
+{
+	char *addr = kmap_local_page(page);
+	memset(addr + offset, 0, len);
+	flush_dcache_page(page);
+	kunmap_local(addr);
+}
+
+/**
+ * folio_zero_segments() - Zero two byte ranges in a folio.
+ * @folio: The folio to write to.
+ * @start1: The first byte to zero.
+ * @xend1: One more than the last byte in the first range.
+ * @start2: The first byte to zero in the second range.
+ * @xend2: One more than the last byte in the second range.
+ */
+static inline void folio_zero_segments(struct folio *folio,
+		size_t start1, size_t xend1, size_t start2, size_t xend2)
+{
+	zero_user_segments(&folio->page, start1, xend1, start2, xend2);
+}
+
+/**
+ * folio_zero_segment() - Zero a byte range in a folio.
+ * @folio: The folio to write to.
+ * @start: The first byte to zero.
+ * @xend: One more than the last byte to zero.
+ */
+static inline void folio_zero_segment(struct folio *folio,
+		size_t start, size_t xend)
+{
+	zero_user_segments(&folio->page, start, xend, 0, 0);
+}
+
+/**
+ * folio_zero_range() - Zero a byte range in a folio.
+ * @folio: The folio to write to.
+ * @start: The first byte to zero.
+ * @length: The number of bytes to zero.
+ */
+static inline void folio_zero_range(struct folio *folio,
+		size_t start, size_t length)
+{
+	zero_user_segments(&folio->page, start, start + length, 0, 0);
+}
+
+#endif /* _LINUX_HIGHMEM_EXTRA_H */