[PATCH v5 06/15] linux/mm.h: move page_address() and others to mm/page_address.h

Max Kellermann
2024-04-30T15:29:53Z

Prepare to reduce dependencies on linux/mm.h.

page_address() is used by the following popular headers:

- linux/bio.h
- linux/bvec.h
- linux/highmem.h
- linux/scatterlist.h
- linux/skbuff.h

Moving it to a separate lean header will allow us to avoid the
dependency on linux/mm.h.

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
---
include/linux/mm.h | 56 +-------------------------
include/linux/mm/page_address.h | 71 +++++++++++++++++++++++++++++++++
2 files changed, 72 insertions(+), 55 deletions(-)
create mode 100644 include/linux/mm/page_address.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 84013f24a6a7..0dea734194aa 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2,7 +2,7 @@
#ifndef _LINUX_MM_H
#define _LINUX_MM_H

-#include <linux/mm/page_kasan_tag.h>
+#include <linux/mm/page_address.h>
#include <linux/mm/page_section.h>
#include <linux/errno.h>
#include <linux/mmdebug.h>
@@ -105,10 +105,6 @@ extern int mmap_rnd_compat_bits __read_mostly;
#define __pa_symbol(x) __pa(RELOC_HIDE((unsigned long)(x), 0))
#endif

-#ifndef page_to_virt
-#define page_to_virt(x) __va(PFN_PHYS(page_to_pfn(x)))
-#endif
-
#ifndef lm_alias
#define lm_alias(x) __va(__pa_symbol(x))
#endif
@@ -212,14 +208,6 @@ int overcommit_kbytes_handler(struct ctl_table *, int, void *, size_t *,
int overcommit_policy_handler(struct ctl_table *, int, void *, size_t *,
loff_t *);

-#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
-#define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
-#define folio_page_idx(folio, p) (page_to_pfn(p) - folio_pfn(folio))
-#else
-#define nth_page(page,n) ((page) + (n))
-#define folio_page_idx(folio, p) ((p) - &(folio)->page)
-#endif
-
/* to align the pointer to the (next) page boundary */
#define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)

@@ -2182,44 +2170,6 @@ static inline int arch_make_folio_accessible(struct folio *folio)
*/
#include <linux/vmstat.h>

-#if defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL)
-#define HASHED_PAGE_VIRTUAL
-#endif
-
-#if defined(WANT_PAGE_VIRTUAL)
-static inline void *page_address(const struct page *page)
-{
- return page->virtual;
-}
-static inline void set_page_address(struct page *page, void *address)
-{
- page->virtual = address;
-}
-#define page_address_init() do { } while(0)
-#endif
-
-#if defined(HASHED_PAGE_VIRTUAL)
-void *page_address(const struct page *page);
-void set_page_address(struct page *page, void *virtual);
-void page_address_init(void);
-#endif
-
-static __always_inline void *lowmem_page_address(const struct page *page)
-{
- return page_to_virt(page);
-}
-
-#if !defined(HASHED_PAGE_VIRTUAL) && !defined(WANT_PAGE_VIRTUAL)
-#define page_address(page) lowmem_page_address(page)
-#define set_page_address(page, address) do { } while(0)
-#define page_address_init() do { } while(0)
-#endif
-
-static inline void *folio_address(const struct folio *folio)
-{
- return page_address(&folio->page);
-}
-
extern pgoff_t __page_file_index(struct page *page);

/*
@@ -2282,10 +2232,6 @@ static inline void clear_page_pfmemalloc(struct page *page)
*/
extern void pagefault_out_of_memory(void);

-#define offset_in_page(p) ((unsigned long)(p) & ~PAGE_MASK)
-#define offset_in_thp(page, p) ((unsigned long)(p) & (thp_size(page) - 1))
-#define offset_in_folio(folio, p) ((unsigned long)(p) & (folio_size(folio) - 1))
-
/*
* Parameter block passed down to zap_pte_range in exceptional cases.
*/
diff --git a/include/linux/mm/page_address.h b/include/linux/mm/page_address.h
new file mode 100644
index 000000000000..630fc4e2be95
--- /dev/null
+++ b/include/linux/mm/page_address.h
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_MM_PAGE_ADDRESS_H
+#define _LINUX_MM_PAGE_ADDRESS_H
+
+#include <linux/mm_types.h> // for struct page
+#include <linux/mm/page_kasan_tag.h> // needed by the page_to_virt() macro on some architectures (e.g. arm64)
+#include <asm/page.h> // for PAGE_MASK, page_to_virt()
+
+#if defined(CONFIG_FLATMEM)
+#include <linux/mmzone.h> // for memmap (used by __pfn_to_page())
+#elif defined(CONFIG_SPARSEMEM_VMEMMAP)
+#include <asm/pgtable.h> // for vmemmap (used by __pfn_to_page())
+#elif defined(CONFIG_SPARSEMEM)
+#include <linux/mm/page_section.h> // for page_to_section() (used by __page_to_pfn())
+#endif
+
+#ifndef page_to_virt
+#define page_to_virt(x) __va(PFN_PHYS(page_to_pfn(x)))
+#endif
+
+#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
+#define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
+#define folio_page_idx(folio, p) (page_to_pfn(p) - folio_pfn(folio))
+#else
+#define nth_page(page,n) ((page) + (n))
+#define folio_page_idx(folio, p) ((p) - &(folio)->page)
+#endif
+
+#if defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL)
+#define HASHED_PAGE_VIRTUAL
+#endif
+
+#if defined(WANT_PAGE_VIRTUAL)
+static inline void *page_address(const struct page *page)
+{
+ return page->virtual;
+}
+static inline void set_page_address(struct page *page, void *address)
+{
+ page->virtual = address;
+}
+#define page_address_init() do { } while(0)
+#endif
+
+#if defined(HASHED_PAGE_VIRTUAL)
+void *page_address(const struct page *page);
+void set_page_address(struct page *page, void *virtual);
+void page_address_init(void);
+#endif
+
+static __always_inline void *lowmem_page_address(const struct page *page)
+{
+ return page_to_virt(page);
+}
+
+#if !defined(HASHED_PAGE_VIRTUAL) && !defined(WANT_PAGE_VIRTUAL)
+#define page_address(page) lowmem_page_address(page)
+#define set_page_address(page, address) do { } while(0)
+#define page_address_init() do { } while(0)
+#endif
+
+static inline void *folio_address(const struct folio *folio)
+{
+ return page_address(&folio->page);
+}
+
+#define offset_in_page(p) ((unsigned long)(p) & ~PAGE_MASK)
+#define offset_in_thp(page, p) ((unsigned long)(p) & (thp_size(page) - 1))
+#define offset_in_folio(folio, p) ((unsigned long)(p) & (folio_size(folio) - 1))
+
+#endif /* _LINUX_MM_PAGE_ADDRESS_H */
--
2.39.2