[PATCH v2 00/14] Fast kernel headers: split linux/mm.h

[PATCH v2 00/14] Fast kernel headers: split linux/mm.h

[Max Kellermann]

This patch set aims to clean up the linux/mm.h header and reduce
dependencies on it by moving parts out.

The goal was to eliminate dependencies on linux/mm.h from other
popular headers such as highmem.h and dma-mapping.h, and I started by
checking which symbols were really used and moved those declarations
to separate slim headers.

---
v1 -> v2: added more explanations to commit messages; renamed several
  new headers from page_*.h to folio_*.h as suggested by Matthew
  Wilcox; rebase on linux-next; fix build failures on architectures
  um,nios2,hexagon by adding more missing includes

Max Kellermann (14):
  drivers: add missing includes on linux/mm.h (and others)
  include/drm/drm_gem.h: add poll_table_struct forward declaration
  linux/mm.h: move page_kasan_tag() to mm/page_kasan_tag.h
  linux/mm.h: move section functions to mm/page_section.h
  linux/mm.h: move page_address() and others to mm/page_address.h
  linux/mm.h: move folio_size(), ... to mm/folio_size.h
  linux/mm.h: move folio_next() to mm/folio_next.h
  linux/mm.h: move devmap-related declarations to mm/devmap_managed.h
  linux/mm.h: move usage count functions to mm/folio_usage.h
  linux/mm.h: move page_zone_id() and more to mm/folio_zone.h
  linux/mm.h: move pfmemalloc-related functions to pfmemalloc.h
  linux/mm.h: move is_vmalloc_addr() to mm/vmalloc_addr.h
  linux/mm.h: move high_memory to mm/high_memory.h
  include: reduce dependencies on linux/mm.h

 MAINTAINERS                                   |   1 +
 arch/arm/include/asm/memory.h                 |   4 +
 arch/arm/include/asm/pgtable.h                |   2 +
 arch/arm/mm/iomap.c                           |   3 +
 arch/csky/include/asm/page.h                  |   1 +
 arch/hexagon/include/asm/mem-layout.h         |   4 +
 arch/m68k/include/asm/page_mm.h               |   1 +
 arch/m68k/include/asm/pgtable_mm.h            |   1 +
 arch/parisc/include/asm/floppy.h              |   1 +
 arch/powerpc/include/asm/book3s/32/pgtable.h  |   4 +
 arch/powerpc/include/asm/nohash/32/pgtable.h  |   1 +
 arch/powerpc/include/asm/page.h               |   1 +
 arch/x86/include/asm/floppy.h                 |   1 +
 arch/x86/include/asm/pgtable_32_areas.h       |   4 +
 drivers/comedi/comedi_buf.c                   |   1 +
 .../qat/qat_common/adf_gen4_pm_debugfs.c      |   1 +
 drivers/dma/dma-axi-dmac.c                    |   1 +
 drivers/dma/sh/rcar-dmac.c                    |   1 +
 drivers/firmware/qcom/qcom_scm-legacy.c       |   1 +
 drivers/firmware/qcom/qcom_scm-smc.c          |   1 +
 drivers/firmware/raspberrypi.c                |   1 +
 drivers/iio/buffer/industrialio-buffer-dma.c  |   1 +
 drivers/iommu/iommufd/ioas.c                  |   2 +
 drivers/iommu/iommufd/selftest.c              |   1 +
 drivers/media/platform/mediatek/vpu/mtk_vpu.c |   1 +
 drivers/media/platform/ti/omap/omap_voutlib.c |   1 +
 drivers/misc/bcm-vk/bcm_vk_dev.c              |   1 +
 drivers/misc/fastrpc.c                        |   1 +
 drivers/misc/genwqe/card_dev.c                |   1 +
 drivers/misc/uacce/uacce.c                    |   1 +
 drivers/mtd/nand/onenand/onenand_samsung.c    |   1 +
 drivers/mtd/spi-nor/core.h                    |   2 +
 drivers/pci/p2pdma.c                          |   1 +
 drivers/pci/pci.c                             |   1 +
 drivers/remoteproc/remoteproc_core.c          |   1 +
 drivers/soc/qcom/rmtfs_mem.c                  |   1 +
 drivers/spi/spi-aspeed-smc.c                  |   1 +
 drivers/spi/spi-bcm2835.c                     |   2 +
 drivers/spi/spi-intel.c                       |   1 +
 drivers/virtio/virtio_ring.c                  |   1 +
 include/drm/drm_file.h                        |   1 +
 include/linux/bio.h                           |   2 +
 include/linux/dma-mapping.h                   |   1 +
 include/linux/highmem-internal.h              |   2 +
 include/linux/highmem.h                       |   4 +-
 include/linux/huge_mm.h                       |   2 +
 include/linux/iommu.h                         |   1 +
 include/linux/mm.h                            | 582 +-----------------
 include/linux/mm/devmap_managed.h             |  37 ++
 include/linux/mm/folio_next.h                 |  27 +
 include/linux/mm/folio_size.h                 | 150 +++++
 include/linux/mm/folio_usage.h                | 177 ++++++
 include/linux/mm/folio_zone.h                 |  38 ++
 include/linux/mm/high_memory.h                |   7 +
 include/linux/mm/page_address.h               |  71 +++
 include/linux/mm/page_kasan_tag.h             |  66 ++
 include/linux/mm/page_section.h               |  23 +
 include/linux/mm/pfmemalloc.h                 |  52 ++
 include/linux/mm/vmalloc_addr.h               |  33 +
 include/linux/nvme-keyring.h                  |   2 +
 include/linux/scatterlist.h                   |   8 +-
 include/linux/skbuff.h                        |   4 +
 kernel/dma/ops_helpers.c                      |   1 +
 kernel/dma/remap.c                            |   1 +
 lib/scatterlist.c                             |   1 +
 mm/dmapool.c                                  |   1 +
 66 files changed, 777 insertions(+), 575 deletions(-)
 create mode 100644 include/linux/mm/devmap_managed.h
 create mode 100644 include/linux/mm/folio_next.h
 create mode 100644 include/linux/mm/folio_size.h
 create mode 100644 include/linux/mm/folio_usage.h
 create mode 100644 include/linux/mm/folio_zone.h
 create mode 100644 include/linux/mm/high_memory.h
 create mode 100644 include/linux/mm/page_address.h
 create mode 100644 include/linux/mm/page_kasan_tag.h
 create mode 100644 include/linux/mm/page_section.h
 create mode 100644 include/linux/mm/pfmemalloc.h
 create mode 100644 include/linux/mm/vmalloc_addr.h

-- 
2.39.2

[PATCH v2 01/14] drivers: add missing includes on linux/mm.h (and others)

[Max Kellermann]

After developing the other patches in this series, I had lots of build
failures because "#include <linux/mm.h>" was missing.  This patch
fixes those build failures by adding the missing "#include" lines.  To
allow bisects, it is ordered before the others.

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
---
 arch/arm/mm/iomap.c                                       | 3 +++
 drivers/comedi/comedi_buf.c                               | 1 +
 drivers/crypto/intel/qat/qat_common/adf_gen4_pm_debugfs.c | 1 +
 drivers/dma/dma-axi-dmac.c                                | 1 +
 drivers/dma/sh/rcar-dmac.c                                | 1 +
 drivers/firmware/qcom/qcom_scm-legacy.c                   | 1 +
 drivers/firmware/qcom/qcom_scm-smc.c                      | 1 +
 drivers/firmware/raspberrypi.c                            | 1 +
 drivers/iio/buffer/industrialio-buffer-dma.c              | 1 +
 drivers/iommu/iommufd/ioas.c                              | 2 ++
 drivers/iommu/iommufd/selftest.c                          | 1 +
 drivers/media/platform/mediatek/vpu/mtk_vpu.c             | 1 +
 drivers/media/platform/ti/omap/omap_voutlib.c             | 1 +
 drivers/misc/bcm-vk/bcm_vk_dev.c                          | 1 +
 drivers/misc/fastrpc.c                                    | 1 +
 drivers/misc/genwqe/card_dev.c                            | 1 +
 drivers/misc/uacce/uacce.c                                | 1 +
 drivers/mtd/spi-nor/core.h                                | 2 ++
 drivers/pci/p2pdma.c                                      | 1 +
 drivers/pci/pci.c                                         | 1 +
 drivers/remoteproc/remoteproc_core.c                      | 1 +
 drivers/soc/qcom/rmtfs_mem.c                              | 1 +
 drivers/spi/spi-aspeed-smc.c                              | 1 +
 drivers/spi/spi-bcm2835.c                                 | 2 ++
 drivers/spi/spi-intel.c                                   | 1 +
 drivers/virtio/virtio_ring.c                              | 1 +
 include/linux/huge_mm.h                                   | 2 ++
 include/linux/iommu.h                                     | 1 +
 include/linux/nvme-keyring.h                              | 2 ++
 include/linux/scatterlist.h                               | 6 ++++++
 kernel/dma/ops_helpers.c                                  | 1 +
 kernel/dma/remap.c                                        | 1 +
 mm/dmapool.c                                              | 1 +
 33 files changed, 45 insertions(+)

diff --git a/arch/arm/mm/iomap.c b/arch/arm/mm/iomap.c
index 415d0a454237..9873d8156908 100644
--- a/arch/arm/mm/iomap.c
+++ b/arch/arm/mm/iomap.c
@@ -29,6 +29,9 @@ EXPORT_SYMBOL(ioport_unmap);
 #endif
 
 #ifdef CONFIG_PCI
+
+#include <asm/pgtable.h> // for VMALLOC_*
+
 unsigned long pcibios_min_io = 0x1000;
 EXPORT_SYMBOL(pcibios_min_io);
 
diff --git a/drivers/comedi/comedi_buf.c b/drivers/comedi/comedi_buf.c
index 393966c09740..23b07ebc97ca 100644
--- a/drivers/comedi/comedi_buf.c
+++ b/drivers/comedi/comedi_buf.c
@@ -10,6 +10,7 @@
 #include <linux/vmalloc.h>
 #include <linux/slab.h>
 #include <linux/comedi/comedidev.h>
+#include <asm/pgtable.h> // for PAGE_KERNEL*
 #include "comedi_internal.h"
 
 #ifdef PAGE_KERNEL_NOCACHE
diff --git a/drivers/crypto/intel/qat/qat_common/adf_gen4_pm_debugfs.c b/drivers/crypto/intel/qat/qat_common/adf_gen4_pm_debugfs.c
index ee0b5079de3e..c9b2787baac7 100644
--- a/drivers/crypto/intel/qat/qat_common/adf_gen4_pm_debugfs.c
+++ b/drivers/crypto/intel/qat/qat_common/adf_gen4_pm_debugfs.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /* Copyright(c) 2023 Intel Corporation */
 #include <linux/dma-mapping.h>
+#include <linux/fs.h> // for simple_read_from_buffer()
 #include <linux/kernel.h>
 #include <linux/string_helpers.h>
 #include <linux/stringify.h>
diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
index 4e339c04fc1e..0c98bf0e4b5d 100644
--- a/drivers/dma/dma-axi-dmac.c
+++ b/drivers/dma/dma-axi-dmac.c
@@ -15,6 +15,7 @@
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
+#include <linux/mm.h> // for PAGE_ALIGN()
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_dma.h>
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index 40482cb73d79..784da367665c 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -12,6 +12,7 @@
 #include <linux/dmaengine.h>
 #include <linux/interrupt.h>
 #include <linux/list.h>
+#include <linux/mm.h> // for PAGE_ALIGN()
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
diff --git a/drivers/firmware/qcom/qcom_scm-legacy.c b/drivers/firmware/qcom/qcom_scm-legacy.c
index 029e6d117cb8..01e082c7163c 100644
--- a/drivers/firmware/qcom/qcom_scm-legacy.c
+++ b/drivers/firmware/qcom/qcom_scm-legacy.c
@@ -5,6 +5,7 @@
 
 #include <linux/slab.h>
 #include <linux/io.h>
+#include <linux/mm.h> // for PAGE_ALIGN()
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/errno.h>
diff --git a/drivers/firmware/qcom/qcom_scm-smc.c b/drivers/firmware/qcom/qcom_scm-smc.c
index 16cf88acfa8e..a5c74d8996fe 100644
--- a/drivers/firmware/qcom/qcom_scm-smc.c
+++ b/drivers/firmware/qcom/qcom_scm-smc.c
@@ -5,6 +5,7 @@
 #include <linux/io.h>
 #include <linux/errno.h>
 #include <linux/delay.h>
+#include <linux/mm.h> // for PAGE_ALIGN()
 #include <linux/mutex.h>
 #include <linux/slab.h>
 #include <linux/types.h>
diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c
index 322aada20f74..beef5c4afef2 100644
--- a/drivers/firmware/raspberrypi.c
+++ b/drivers/firmware/raspberrypi.c
@@ -9,6 +9,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/kref.h>
 #include <linux/mailbox_client.h>
+#include <linux/mm.h> // for PAGE_ALIGN()
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
diff --git a/drivers/iio/buffer/industrialio-buffer-dma.c b/drivers/iio/buffer/industrialio-buffer-dma.c
index 5610ba67925e..b3ce8c4b101a 100644
--- a/drivers/iio/buffer/industrialio-buffer-dma.c
+++ b/drivers/iio/buffer/industrialio-buffer-dma.c
@@ -6,6 +6,7 @@
 
 #include <linux/slab.h>
 #include <linux/kernel.h>
+#include <linux/mm.h> // for PAGE_ALIGN()
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/workqueue.h>
diff --git a/drivers/iommu/iommufd/ioas.c b/drivers/iommu/iommufd/ioas.c
index 742248276548..40c4942406cd 100644
--- a/drivers/iommu/iommufd/ioas.c
+++ b/drivers/iommu/iommufd/ioas.c
@@ -5,6 +5,8 @@
 #include <linux/interval_tree.h>
 #include <linux/iommufd.h>
 #include <linux/iommu.h>
+#include <linux/capability.h>
+#include <linux/slab.h>
 #include <uapi/linux/iommufd.h>
 
 #include "io_pagetable.h"
diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c
index 8abf9747773e..710789a2add9 100644
--- a/drivers/iommu/iommufd/selftest.c
+++ b/drivers/iommu/iommufd/selftest.c
@@ -5,6 +5,7 @@
  */
 #include <linux/slab.h>
 #include <linux/iommu.h>
+#include <linux/mm.h> // for GUP_PIN_COUNTING_BIAS
 #include <linux/xarray.h>
 #include <linux/file.h>
 #include <linux/anon_inodes.h>
diff --git a/drivers/media/platform/mediatek/vpu/mtk_vpu.c b/drivers/media/platform/mediatek/vpu/mtk_vpu.c
index 7243604a82a5..885b873982e4 100644
--- a/drivers/media/platform/mediatek/vpu/mtk_vpu.c
+++ b/drivers/media/platform/mediatek/vpu/mtk_vpu.c
@@ -8,6 +8,7 @@
 #include <linux/firmware.h>
 #include <linux/interrupt.h>
 #include <linux/iommu.h>
+#include <linux/mm.h> // for totalram_pages()
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
diff --git a/drivers/media/platform/ti/omap/omap_voutlib.c b/drivers/media/platform/ti/omap/omap_voutlib.c
index 0ac46458e41c..3b653b49cc48 100644
--- a/drivers/media/platform/ti/omap/omap_voutlib.c
+++ b/drivers/media/platform/ti/omap/omap_voutlib.c
@@ -18,6 +18,7 @@
  *
  */
 
+#include <linux/mm.h> // for PAGE_ALIGN()
 #include <linux/module.h>
 #include <linux/errno.h>
 #include <linux/kernel.h>
diff --git a/drivers/misc/bcm-vk/bcm_vk_dev.c b/drivers/misc/bcm-vk/bcm_vk_dev.c
index d4a96137728d..c5a39a8189bf 100644
--- a/drivers/misc/bcm-vk/bcm_vk_dev.c
+++ b/drivers/misc/bcm-vk/bcm_vk_dev.c
@@ -11,6 +11,7 @@
 #include <linux/interrupt.h>
 #include <linux/panic_notifier.h>
 #include <linux/kref.h>
+#include <linux/mm.h> // for io_remap_pfn_range()
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/pci.h>
diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index dbd26c3b245b..35701e9ec28e 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -10,6 +10,7 @@
 #include <linux/idr.h>
 #include <linux/list.h>
 #include <linux/miscdevice.h>
+#include <linux/mm.h> // for find_vma()
 #include <linux/module.h>
 #include <linux/of_address.h>
 #include <linux/of.h>
diff --git a/drivers/misc/genwqe/card_dev.c b/drivers/misc/genwqe/card_dev.c
index 4441aca2280a..ce3acb938ca6 100644
--- a/drivers/misc/genwqe/card_dev.c
+++ b/drivers/misc/genwqe/card_dev.c
@@ -17,6 +17,7 @@
 
 #include <linux/kernel.h>
 #include <linux/types.h>
+#include <linux/mm.h> // for struct vm_operations_struct
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/string.h>
diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c
index bdc2e6fda782..af815b8a718e 100644
--- a/drivers/misc/uacce/uacce.c
+++ b/drivers/misc/uacce/uacce.c
@@ -2,6 +2,7 @@
 #include <linux/compat.h>
 #include <linux/dma-mapping.h>
 #include <linux/iommu.h>
+#include <linux/mm.h> // for struct vm_operations_struct
 #include <linux/module.h>
 #include <linux/poll.h>
 #include <linux/slab.h>
diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
index d36c0e072954..0d11ff848a7f 100644
--- a/drivers/mtd/spi-nor/core.h
+++ b/drivers/mtd/spi-nor/core.h
@@ -9,6 +9,8 @@
 
 #include "sfdp.h"
 
+#include <linux/sizes.h> // for SZ_*
+
 #define SPI_NOR_MAX_ID_LEN	6
 /*
  * 256 bytes is a sane default for most older flashes. Newer flashes will
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 4f47a13cb500..ef37ea6c09fc 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -16,6 +16,7 @@
 #include <linux/slab.h>
 #include <linux/genalloc.h>
 #include <linux/memremap.h>
+#include <linux/mm.h> // for VM_MAYSHARE
 #include <linux/percpu-refcount.h>
 #include <linux/random.h>
 #include <linux/seq_buf.h>
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index cfc5b84dc9c9..e2afd992caa7 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -25,6 +25,7 @@
 #include <linux/logic_pio.h>
 #include <linux/pm_wakeup.h>
 #include <linux/device.h>
+#include <linux/pgtable.h> // for pgprot_device()
 #include <linux/pm_runtime.h>
 #include <linux/pci_hotplug.h>
 #include <linux/vmalloc.h>
diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index f276956f2c5c..938220fe29f5 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -18,6 +18,7 @@
 
 #include <linux/delay.h>
 #include <linux/kernel.h>
+#include <linux/mm.h> // for PAGE_ALIGN()
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/panic_notifier.h>
diff --git a/drivers/soc/qcom/rmtfs_mem.c b/drivers/soc/qcom/rmtfs_mem.c
index df850d073102..15c2f6e5eaff 100644
--- a/drivers/soc/qcom/rmtfs_mem.c
+++ b/drivers/soc/qcom/rmtfs_mem.c
@@ -6,6 +6,7 @@
 #include <linux/kernel.h>
 #include <linux/cdev.h>
 #include <linux/err.h>
+#include <linux/mm.h> // for remap_pfn_range()
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/of.h>
diff --git a/drivers/spi/spi-aspeed-smc.c b/drivers/spi/spi-aspeed-smc.c
index bbd417c55e7f..e45f64761e5e 100644
--- a/drivers/spi/spi-aspeed-smc.c
+++ b/drivers/spi/spi-aspeed-smc.c
@@ -11,6 +11,7 @@
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
+#include <linux/sizes.h> // for SZ_*
 #include <linux/spi/spi.h>
 #include <linux/spi/spi-mem.h>
 
diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c
index e1b9b1235787..d8ed5575a9c6 100644
--- a/drivers/spi/spi-bcm2835.c
+++ b/drivers/spi/spi-bcm2835.c
@@ -33,6 +33,8 @@
 #include <linux/slab.h>
 #include <linux/spi/spi.h>
 
+#include <asm/pgtable.h> // for ZERO_PAGE()
+
 /* SPI register offsets */
 #define BCM2835_SPI_CS			0x00
 #define BCM2835_SPI_FIFO		0x04
diff --git a/drivers/spi/spi-intel.c b/drivers/spi/spi-intel.c
index 3e5dcf2b3c8a..cf8e4f1c4d93 100644
--- a/drivers/spi/spi-intel.c
+++ b/drivers/spi/spi-intel.c
@@ -8,6 +8,7 @@
 
 #include <linux/iopoll.h>
 #include <linux/module.h>
+#include <linux/sizes.h> // for SZ_*
 
 #include <linux/mtd/partitions.h>
 #include <linux/mtd/spi-nor.h>
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 49299b1f9ec7..5c3ca44aef42 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -12,6 +12,7 @@
 #include <linux/hrtimer.h>
 #include <linux/dma-mapping.h>
 #include <linux/kmsan.h>
+#include <linux/mm.h> // for PAGE_ALIGN()
 #include <linux/spinlock.h>
 #include <xen/xen.h>
 
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 5adb86af35fc..e3395a9bea81 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -7,6 +7,8 @@
 
 #include <linux/fs.h> /* only for vma_is_dax() */
 
+#include <asm/page.h> // for pmd_t
+
 vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf);
 int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 		  pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr,
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index de839fd01bb8..c49cd93b9c85 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -14,6 +14,7 @@
 #include <linux/err.h>
 #include <linux/of.h>
 #include <linux/iova_bitmap.h>
+#include <linux/uaccess.h> // for copy_struct_from_user()
 
 #define IOMMU_READ	(1 << 0)
 #define IOMMU_WRITE	(1 << 1)
diff --git a/include/linux/nvme-keyring.h b/include/linux/nvme-keyring.h
index e10333d78dbb..9e033850b967 100644
--- a/include/linux/nvme-keyring.h
+++ b/include/linux/nvme-keyring.h
@@ -6,6 +6,8 @@
 #ifndef _NVME_KEYRING_H
 #define _NVME_KEYRING_H
 
+#include <linux/key.h>
+
 #if IS_ENABLED(CONFIG_NVME_KEYRING)
 
 key_serial_t nvme_tls_psk_default(struct key *keyring,
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 77df3d7b18a6..0516e64dc03e 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -8,6 +8,12 @@
 #include <linux/mm.h>
 #include <asm/io.h>
 
+#ifdef CONFIG_UML
+#include <asm/pgtable.h> // for virt_to_page(), page_to_phys()
+#else
+#include <asm/page.h> // for virt_to_page(), page_to_phys()
+#endif
+
 struct scatterlist {
 	unsigned long	page_link;
 	unsigned int	offset;
diff --git a/kernel/dma/ops_helpers.c b/kernel/dma/ops_helpers.c
index af4a6ef48ce0..641363b13bb9 100644
--- a/kernel/dma/ops_helpers.c
+++ b/kernel/dma/ops_helpers.c
@@ -4,6 +4,7 @@
  * the allocated memory contains normal pages in the direct kernel mapping.
  */
 #include <linux/dma-map-ops.h>
+#include <linux/mm.h> // for PAGE_ALIGN()
 
 static struct page *dma_common_vaddr_to_page(void *cpu_addr)
 {
diff --git a/kernel/dma/remap.c b/kernel/dma/remap.c
index 27596f3b4aef..87b3c874d370 100644
--- a/kernel/dma/remap.c
+++ b/kernel/dma/remap.c
@@ -3,6 +3,7 @@
  * Copyright (c) 2014 The Linux Foundation
  */
 #include <linux/dma-map-ops.h>
+#include <linux/mm.h> // for vmap(), PAGE_ALIGN()
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 
diff --git a/mm/dmapool.c b/mm/dmapool.c
index f0bfc6c490f4..b8e23fdc81d7 100644
--- a/mm/dmapool.c
+++ b/mm/dmapool.c
@@ -25,6 +25,7 @@
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/export.h>
+#include <linux/mm.h> // for want_init_on_alloc()
 #include <linux/mutex.h>
 #include <linux/poison.h>
 #include <linux/sched.h>
-- 
2.39.2

[PATCH v2 02/14] include/drm/drm_gem.h: add poll_table_struct forward declaration

[Max Kellermann]

After eliminating includes of linux/mm.h, the following build failure
occurred:

 ./include/drm/drm_file.h:443:45: warning: ‘struct poll_table_struct’ declared inside parameter list will not be visible outside of this definition or declaration
   443 | __poll_t drm_poll(struct file *filp, struct poll_table_struct *wait);
       |                                             ^~~~~~~~~~~~~~~~~
 In file included from drivers/gpu/drm/imagination/pvr_gem.h:12,
                  from drivers/gpu/drm/imagination/pvr_fw.h:9:
 ./include/drm/drm_gem.h:447:27: error: initialization of ‘__poll_t (*)(struct file *, struct poll_table_struct *)’ {aka ‘unsigned int (*)(struct file *, struct poll_table_struct *)’} from incompatible pointer type ‘__poll_t (*)(struct file *, struct poll_table_struct *)’ {aka ‘unsigned int (*)(struct file *, struct poll_table_struct *)’} [-Werror=incompatible-pointer-types]
   447 |         .poll           = drm_poll,\
       |                           ^~~~~~~~

The compiler is confused, and that can be fixed easily by
forward-declaring the struct expicitly.

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
---
 include/drm/drm_file.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
index ab230d3af138..f24ade9f766f 100644
--- a/include/drm/drm_file.h
+++ b/include/drm/drm_file.h
@@ -44,6 +44,7 @@ struct drm_device;
 struct drm_printer;
 struct device;
 struct file;
+struct poll_table_struct;
 
 /*
  * FIXME: Not sure we want to have drm_minor here in the end, but to avoid
-- 
2.39.2

[PATCH v2 03/14] linux/mm.h: move page_kasan_tag() to mm/page_kasan_tag.h

[Max Kellermann]

Prepare to reduce dependencies on linux/mm.h.

page_kasan_tag() is used by the page_to_virt() macro in ARM64 (but
asm/memory.h does not include linux/mm.h).  Thus, in order to be able to use
anything that calls page_to_virt(), linux/mm.h needs to be included.

This would prevent us from moving page_address() to a separate header,
because it calls lowmem_page_address() which in turn calls
page_to_virt().  To prepare for this move, we move page_kasan_tag()
out of linux/mm.h into a separate lean header.

A side effect of this patch is that the <linux/kasan.h> include line
is moved inside the "#ifdef CONFIG_KASAN..." block, i.e. it is not
included at all if KASAN is disabled.

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
---
 MAINTAINERS                       |  1 +
 include/linux/mm.h                | 56 +-------------------------
 include/linux/mm/page_kasan_tag.h | 66 +++++++++++++++++++++++++++++++
 3 files changed, 68 insertions(+), 55 deletions(-)
 create mode 100644 include/linux/mm/page_kasan_tag.h

diff --git a/MAINTAINERS b/MAINTAINERS
index c042ca394893..ad208d8aea4b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14187,6 +14187,7 @@ F:	include/linux/mempolicy.h
 F:	include/linux/mempool.h
 F:	include/linux/memremap.h
 F:	include/linux/mm.h
+F:	include/linux/mm/*.h
 F:	include/linux/mm_*.h
 F:	include/linux/mmzone.h
 F:	include/linux/mmu_notifier.h
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1743bdeab506..c8d909cc1353 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2,6 +2,7 @@
 #ifndef _LINUX_MM_H
 #define _LINUX_MM_H
 
+#include <linux/mm/page_kasan_tag.h>
 #include <linux/errno.h>
 #include <linux/mmdebug.h>
 #include <linux/gfp.h>
@@ -27,7 +28,6 @@
 #include <linux/sizes.h>
 #include <linux/sched.h>
 #include <linux/pgtable.h>
-#include <linux/kasan.h>
 #include <linux/memremap.h>
 #include <linux/slab.h>
 
@@ -1810,60 +1810,6 @@ static inline void vma_set_access_pid_bit(struct vm_area_struct *vma)
 }
 #endif /* CONFIG_NUMA_BALANCING */
 
-#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
-
-/*
- * KASAN per-page tags are stored xor'ed with 0xff. This allows to avoid
- * setting tags for all pages to native kernel tag value 0xff, as the default
- * value 0x00 maps to 0xff.
- */
-
-static inline u8 page_kasan_tag(const struct page *page)
-{
-	u8 tag = KASAN_TAG_KERNEL;
-
-	if (kasan_enabled()) {
-		tag = (page->flags >> KASAN_TAG_PGSHIFT) & KASAN_TAG_MASK;
-		tag ^= 0xff;
-	}
-
-	return tag;
-}
-
-static inline void page_kasan_tag_set(struct page *page, u8 tag)
-{
-	unsigned long old_flags, flags;
-
-	if (!kasan_enabled())
-		return;
-
-	tag ^= 0xff;
-	old_flags = READ_ONCE(page->flags);
-	do {
-		flags = old_flags;
-		flags &= ~(KASAN_TAG_MASK << KASAN_TAG_PGSHIFT);
-		flags |= (tag & KASAN_TAG_MASK) << KASAN_TAG_PGSHIFT;
-	} while (unlikely(!try_cmpxchg(&page->flags, &old_flags, flags)));
-}
-
-static inline void page_kasan_tag_reset(struct page *page)
-{
-	if (kasan_enabled())
-		page_kasan_tag_set(page, KASAN_TAG_KERNEL);
-}
-
-#else /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */
-
-static inline u8 page_kasan_tag(const struct page *page)
-{
-	return 0xff;
-}
-
-static inline void page_kasan_tag_set(struct page *page, u8 tag) { }
-static inline void page_kasan_tag_reset(struct page *page) { }
-
-#endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */
-
 static inline struct zone *page_zone(const struct page *page)
 {
 	return &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)];
diff --git a/include/linux/mm/page_kasan_tag.h b/include/linux/mm/page_kasan_tag.h
new file mode 100644
index 000000000000..1210c62170a3
--- /dev/null
+++ b/include/linux/mm/page_kasan_tag.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_MM_PAGE_KASAN_TAG_H
+#define _LINUX_MM_PAGE_KASAN_TAG_H
+
+#include <linux/types.h>
+
+struct page;
+
+#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
+
+#include <linux/kasan.h>
+#include <linux/mm_types.h> // for struct page
+
+/*
+ * KASAN per-page tags are stored xor'ed with 0xff. This allows to avoid
+ * setting tags for all pages to native kernel tag value 0xff, as the default
+ * value 0x00 maps to 0xff.
+ */
+
+static inline u8 page_kasan_tag(const struct page *page)
+{
+	u8 tag = KASAN_TAG_KERNEL;
+
+	if (kasan_enabled()) {
+		tag = (page->flags >> KASAN_TAG_PGSHIFT) & KASAN_TAG_MASK;
+		tag ^= 0xff;
+	}
+
+	return tag;
+}
+
+static inline void page_kasan_tag_set(struct page *page, u8 tag)
+{
+	unsigned long old_flags, flags;
+
+	if (!kasan_enabled())
+		return;
+
+	tag ^= 0xff;
+	old_flags = READ_ONCE(page->flags);
+	do {
+		flags = old_flags;
+		flags &= ~(KASAN_TAG_MASK << KASAN_TAG_PGSHIFT);
+		flags |= (tag & KASAN_TAG_MASK) << KASAN_TAG_PGSHIFT;
+	} while (unlikely(!try_cmpxchg(&page->flags, &old_flags, flags)));
+}
+
+static inline void page_kasan_tag_reset(struct page *page)
+{
+	if (kasan_enabled())
+		page_kasan_tag_set(page, KASAN_TAG_KERNEL);
+}
+
+#else /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */
+
+static inline u8 page_kasan_tag(const struct page *page)
+{
+	return 0xff;
+}
+
+static inline void page_kasan_tag_set(struct page *page, u8 tag) { }
+static inline void page_kasan_tag_reset(struct page *page) { }
+
+#endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */
+
+#endif /* _LINUX_MM_PAGE_KASAN_TAG_H */
-- 
2.39.2

[PATCH v2 04/14] linux/mm.h: move section functions to mm/page_section.h

[Max Kellermann]

Prepare to reduce dependencies on linux/mm.h.

page_to_section() is used by __page_to_pfn() (but
asm-generic/memory_model.h does not include linux/mm.h).  Thus, in
order to be able to use anything that calls page_to_pfn(), linux/mm.h
needs to be included.

This would prevent us from moving page_address() to a separate header,
because it calls lowmem_page_address() which in turn calls
page_to_virt() and then page_to_pfn().  To prepare for this move, we
move page_to_section() out of linux/mm.h into a separate lean header.

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
---
 include/linux/mm.h              | 18 +-----------------
 include/linux/mm/page_section.h | 23 +++++++++++++++++++++++
 2 files changed, 24 insertions(+), 17 deletions(-)
 create mode 100644 include/linux/mm/page_section.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index c8d909cc1353..7c3d2bd69818 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3,6 +3,7 @@
 #define _LINUX_MM_H
 
 #include <linux/mm/page_kasan_tag.h>
+#include <linux/mm/page_section.h>
 #include <linux/errno.h>
 #include <linux/mmdebug.h>
 #include <linux/gfp.h>
@@ -1627,10 +1628,6 @@ static inline bool is_nommu_shared_mapping(vm_flags_t flags)
 }
 #endif
 
-#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
-#define SECTION_IN_PAGE_FLAGS
-#endif
-
 /*
  * The identification function is mainly used by the buddy allocator for
  * determining if two pages could be buddies. We are not really identifying
@@ -1830,19 +1827,6 @@ static inline pg_data_t *folio_pgdat(const struct folio *folio)
 	return page_pgdat(&folio->page);
 }
 
-#ifdef SECTION_IN_PAGE_FLAGS
-static inline void set_page_section(struct page *page, unsigned long section)
-{
-	page->flags &= ~(SECTIONS_MASK << SECTIONS_PGSHIFT);
-	page->flags |= (section & SECTIONS_MASK) << SECTIONS_PGSHIFT;
-}
-
-static inline unsigned long page_to_section(const struct page *page)
-{
-	return (page->flags >> SECTIONS_PGSHIFT) & SECTIONS_MASK;
-}
-#endif
-
 /**
  * folio_pfn - Return the Page Frame Number of a folio.
  * @folio: The folio.
diff --git a/include/linux/mm/page_section.h b/include/linux/mm/page_section.h
new file mode 100644
index 000000000000..e4558c2691b8
--- /dev/null
+++ b/include/linux/mm/page_section.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_MM_PAGE_SECTION_H
+#define _LINUX_MM_PAGE_SECTION_H
+
+#include <linux/mm_types.h> // for struct page
+#include <linux/mmzone.h> // for SECTIONS_*
+
+#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
+#define SECTION_IN_PAGE_FLAGS
+
+static inline void set_page_section(struct page *page, unsigned long section)
+{
+	page->flags &= ~(SECTIONS_MASK << SECTIONS_PGSHIFT);
+	page->flags |= (section & SECTIONS_MASK) << SECTIONS_PGSHIFT;
+}
+
+static inline unsigned long page_to_section(const struct page *page)
+{
+	return (page->flags >> SECTIONS_PGSHIFT) & SECTIONS_MASK;
+}
+#endif
+
+#endif /* _LINUX_MM_PAGE_SECTION_H */
-- 
2.39.2

[PATCH v2 05/14] linux/mm.h: move page_address() and others to mm/page_address.h

[Max Kellermann]

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 7c3d2bd69818..57c091e7579e 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>
@@ -103,10 +103,6 @@ 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
@@ -210,14 +206,6 @@ 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)
 
@@ -2122,44 +2110,6 @@ static inline int arch_make_folio_accessible(struct folio *folio)
  */
 #include <linux/vmstat.h>
 
-static __always_inline void *lowmem_page_address(const struct page *page)
-{
-	return page_to_virt(page);
-}
-
-#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
-
-#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);
 
 /*
@@ -2222,10 +2172,6 @@ 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..e1aaacc5003f
--- /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
+
+static __always_inline void *lowmem_page_address(const struct page *page)
+{
+	return page_to_virt(page);
+}
+
+#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
+
+#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

[PATCH v2 06/14] linux/mm.h: move folio_size(), ... to mm/folio_size.h

[Max Kellermann]

Prepare to reduce dependencies on linux/mm.h.

folio_size()/page_size() are used by the following popular headers:

- linux/highmem.h
- linux/iov_iter.h
- linux/pagemap.h

Moving them to a separate lean header will allow us to avoid the
dependency on linux/mm.h.  Additionally, it allows us to move
folio_next() to a separate header, because it needs folio_nr_pages()
which is also moved to folio_size.h.

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
---
 include/linux/mm.h            | 140 +------------------------------
 include/linux/mm/folio_size.h | 150 ++++++++++++++++++++++++++++++++++
 2 files changed, 151 insertions(+), 139 deletions(-)
 create mode 100644 include/linux/mm/folio_size.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 57c091e7579e..9dea6477b4ac 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2,6 +2,7 @@
 #ifndef _LINUX_MM_H
 #define _LINUX_MM_H
 
+#include <linux/mm/folio_size.h>
 #include <linux/mm/page_address.h>
 #include <linux/mm/page_section.h>
 #include <linux/errno.h>
@@ -1054,38 +1055,6 @@ int vma_is_stack_for_current(struct vm_area_struct *vma);
 struct mmu_gather;
 struct inode;
 
-/*
- * compound_order() can be called without holding a reference, which means
- * that niceties like page_folio() don't work.  These callers should be
- * prepared to handle wild return values.  For example, PG_head may be
- * set before the order is initialised, or this may be a tail page.
- * See compaction.c for some good examples.
- */
-static inline unsigned int compound_order(struct page *page)
-{
-	struct folio *folio = (struct folio *)page;
-
-	if (!test_bit(PG_head, &folio->flags))
-		return 0;
-	return folio->_flags_1 & 0xff;
-}
-
-/**
- * folio_order - The allocation order of a folio.
- * @folio: The folio.
- *
- * A folio is composed of 2^order pages.  See get_order() for the definition
- * of order.
- *
- * Return: The order of the folio.
- */
-static inline unsigned int folio_order(struct folio *folio)
-{
-	if (!folio_test_large(folio))
-		return 0;
-	return folio->_flags_1 & 0xff;
-}
-
 #include <linux/huge_mm.h>
 
 /*
@@ -1299,39 +1268,6 @@ unsigned long nr_free_buffer_pages(void);
 
 void destroy_large_folio(struct folio *folio);
 
-/* Returns the number of bytes in this potentially compound page. */
-static inline unsigned long page_size(struct page *page)
-{
-	return PAGE_SIZE << compound_order(page);
-}
-
-/* Returns the number of bits needed for the number of bytes in a page */
-static inline unsigned int page_shift(struct page *page)
-{
-	return PAGE_SHIFT + compound_order(page);
-}
-
-/**
- * thp_order - Order of a transparent huge page.
- * @page: Head page of a transparent huge page.
- */
-static inline unsigned int thp_order(struct page *page)
-{
-	VM_BUG_ON_PGFLAGS(PageTail(page), page);
-	return compound_order(page);
-}
-
-/**
- * thp_size - Size of a transparent huge page.
- * @page: Head page of a transparent huge page.
- *
- * Return: Number of bytes in this page.
- */
-static inline unsigned long thp_size(struct page *page)
-{
-	return PAGE_SIZE << thp_order(page);
-}
-
 #ifdef CONFIG_MMU
 /*
  * Do pte_mkwrite, but only if the vma says VM_WRITE.  We do this when
@@ -1971,50 +1907,6 @@ static inline void set_page_links(struct page *page, enum zone_type zone,
 #endif
 }
 
-/**
- * folio_nr_pages - The number of pages in the folio.
- * @folio: The folio.
- *
- * Return: A positive power of two.
- */
-static inline long folio_nr_pages(struct folio *folio)
-{
-	if (!folio_test_large(folio))
-		return 1;
-#ifdef CONFIG_64BIT
-	return folio->_folio_nr_pages;
-#else
-	return 1L << (folio->_flags_1 & 0xff);
-#endif
-}
-
-/*
- * compound_nr() returns the number of pages in this potentially compound
- * page.  compound_nr() can be called on a tail page, and is defined to
- * return 1 in that case.
- */
-static inline unsigned long compound_nr(struct page *page)
-{
-	struct folio *folio = (struct folio *)page;
-
-	if (!test_bit(PG_head, &folio->flags))
-		return 1;
-#ifdef CONFIG_64BIT
-	return folio->_folio_nr_pages;
-#else
-	return 1L << (folio->_flags_1 & 0xff);
-#endif
-}
-
-/**
- * thp_nr_pages - The number of regular pages in this huge page.
- * @page: The head page of a huge page.
- */
-static inline int thp_nr_pages(struct page *page)
-{
-	return folio_nr_pages((struct folio *)page);
-}
-
 /**
  * folio_next - Move to the next physical folio.
  * @folio: The folio we're currently operating on.
@@ -2034,36 +1926,6 @@ static inline struct folio *folio_next(struct folio *folio)
 	return (struct folio *)folio_page(folio, folio_nr_pages(folio));
 }
 
-/**
- * folio_shift - The size of the memory described by this folio.
- * @folio: The folio.
- *
- * A folio represents a number of bytes which is a power-of-two in size.
- * This function tells you which power-of-two the folio is.  See also
- * folio_size() and folio_order().
- *
- * Context: The caller should have a reference on the folio to prevent
- * it from being split.  It is not necessary for the folio to be locked.
- * Return: The base-2 logarithm of the size of this folio.
- */
-static inline unsigned int folio_shift(struct folio *folio)
-{
-	return PAGE_SHIFT + folio_order(folio);
-}
-
-/**
- * folio_size - The number of bytes in a folio.
- * @folio: The folio.
- *
- * Context: The caller should have a reference on the folio to prevent
- * it from being split.  It is not necessary for the folio to be locked.
- * Return: The number of bytes in this folio.
- */
-static inline size_t folio_size(struct folio *folio)
-{
-	return PAGE_SIZE << folio_order(folio);
-}
-
 /**
  * folio_estimated_sharers - Estimate the number of sharers of a folio.
  * @folio: The folio.
diff --git a/include/linux/mm/folio_size.h b/include/linux/mm/folio_size.h
new file mode 100644
index 000000000000..dd8af39ef572
--- /dev/null
+++ b/include/linux/mm/folio_size.h
@@ -0,0 +1,150 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_MM_FOLIO_SIZE_H
+#define _LINUX_MM_FOLIO_SIZE_H
+
+#include <linux/bitops.h> // for test_bit()
+#include <linux/mmdebug.h> // for VM_BUG_ON_PGFLAGS()
+#include <linux/mm_types.h> // for struct page
+#include <linux/page-flags.h> // for folio_test_large()
+#include <asm/page.h> // for PAGE_SIZE, PAGE_SHIFT
+
+/*
+ * compound_order() can be called without holding a reference, which means
+ * that niceties like page_folio() don't work.  These callers should be
+ * prepared to handle wild return values.  For example, PG_head may be
+ * set before the order is initialised, or this may be a tail page.
+ * See compaction.c for some good examples.
+ */
+static inline unsigned int compound_order(struct page *page)
+{
+	struct folio *folio = (struct folio *)page;
+
+	if (!test_bit(PG_head, &folio->flags))
+		return 0;
+	return folio->_flags_1 & 0xff;
+}
+
+/**
+ * folio_order - The allocation order of a folio.
+ * @folio: The folio.
+ *
+ * A folio is composed of 2^order pages.  See get_order() for the definition
+ * of order.
+ *
+ * Return: The order of the folio.
+ */
+static inline unsigned int folio_order(struct folio *folio)
+{
+	if (!folio_test_large(folio))
+		return 0;
+	return folio->_flags_1 & 0xff;
+}
+
+/* Returns the number of bytes in this potentially compound page. */
+static inline unsigned long page_size(struct page *page)
+{
+	return PAGE_SIZE << compound_order(page);
+}
+
+/* Returns the number of bits needed for the number of bytes in a page */
+static inline unsigned int page_shift(struct page *page)
+{
+	return PAGE_SHIFT + compound_order(page);
+}
+
+/**
+ * thp_order - Order of a transparent huge page.
+ * @page: Head page of a transparent huge page.
+ */
+static inline unsigned int thp_order(struct page *page)
+{
+	VM_BUG_ON_PGFLAGS(PageTail(page), page);
+	return compound_order(page);
+}
+
+/**
+ * thp_size - Size of a transparent huge page.
+ * @page: Head page of a transparent huge page.
+ *
+ * Return: Number of bytes in this page.
+ */
+static inline unsigned long thp_size(struct page *page)
+{
+	return PAGE_SIZE << thp_order(page);
+}
+
+/**
+ * folio_nr_pages - The number of pages in the folio.
+ * @folio: The folio.
+ *
+ * Return: A positive power of two.
+ */
+static inline long folio_nr_pages(struct folio *folio)
+{
+	if (!folio_test_large(folio))
+		return 1;
+#ifdef CONFIG_64BIT
+	return folio->_folio_nr_pages;
+#else
+	return 1L << (folio->_flags_1 & 0xff);
+#endif
+}
+
+/*
+ * compound_nr() returns the number of pages in this potentially compound
+ * page.  compound_nr() can be called on a tail page, and is defined to
+ * return 1 in that case.
+ */
+static inline unsigned long compound_nr(struct page *page)
+{
+	struct folio *folio = (struct folio *)page;
+
+	if (!test_bit(PG_head, &folio->flags))
+		return 1;
+#ifdef CONFIG_64BIT
+	return folio->_folio_nr_pages;
+#else
+	return 1L << (folio->_flags_1 & 0xff);
+#endif
+}
+
+/**
+ * thp_nr_pages - The number of regular pages in this huge page.
+ * @page: The head page of a huge page.
+ */
+static inline int thp_nr_pages(struct page *page)
+{
+	return folio_nr_pages((struct folio *)page);
+}
+
+/**
+ * folio_shift - The size of the memory described by this folio.
+ * @folio: The folio.
+ *
+ * A folio represents a number of bytes which is a power-of-two in size.
+ * This function tells you which power-of-two the folio is.  See also
+ * folio_size() and folio_order().
+ *
+ * Context: The caller should have a reference on the folio to prevent
+ * it from being split.  It is not necessary for the folio to be locked.
+ * Return: The base-2 logarithm of the size of this folio.
+ */
+static inline unsigned int folio_shift(struct folio *folio)
+{
+	return PAGE_SHIFT + folio_order(folio);
+}
+
+/**
+ * folio_size - The number of bytes in a folio.
+ * @folio: The folio.
+ *
+ * Context: The caller should have a reference on the folio to prevent
+ * it from being split.  It is not necessary for the folio to be locked.
+ * Return: The number of bytes in this folio.
+ */
+static inline size_t folio_size(struct folio *folio)
+{
+	return PAGE_SIZE << folio_order(folio);
+}
+
+#endif /* _LINUX_MM_FOLIO_SIZE_H_H */
-- 
2.39.2

[PATCH v2 07/14] linux/mm.h: move folio_next() to mm/folio_next.h

[Max Kellermann]

Prepare to reduce dependencies on linux/mm.h.

folio_next() is used by linux/bio.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            | 20 +-------------------
 include/linux/mm/folio_next.h | 27 +++++++++++++++++++++++++++
 2 files changed, 28 insertions(+), 19 deletions(-)
 create mode 100644 include/linux/mm/folio_next.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 9dea6477b4ac..7d83d6d64f30 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2,6 +2,7 @@
 #ifndef _LINUX_MM_H
 #define _LINUX_MM_H
 
+#include <linux/mm/folio_next.h>
 #include <linux/mm/folio_size.h>
 #include <linux/mm/page_address.h>
 #include <linux/mm/page_section.h>
@@ -1907,25 +1908,6 @@ static inline void set_page_links(struct page *page, enum zone_type zone,
 #endif
 }
 
-/**
- * folio_next - Move to the next physical folio.
- * @folio: The folio we're currently operating on.
- *
- * If you have physically contiguous memory which may span more than
- * one folio (eg a &struct bio_vec), use this function to move from one
- * folio to the next.  Do not use it if the memory is only virtually
- * contiguous as the folios are almost certainly not adjacent to each
- * other.  This is the folio equivalent to writing ``page++``.
- *
- * Context: We assume that the folios are refcounted and/or locked at a
- * higher level and do not adjust the reference counts.
- * Return: The next struct folio.
- */
-static inline struct folio *folio_next(struct folio *folio)
-{
-	return (struct folio *)folio_page(folio, folio_nr_pages(folio));
-}
-
 /**
  * folio_estimated_sharers - Estimate the number of sharers of a folio.
  * @folio: The folio.
diff --git a/include/linux/mm/folio_next.h b/include/linux/mm/folio_next.h
new file mode 100644
index 000000000000..7016e303439c
--- /dev/null
+++ b/include/linux/mm/folio_next.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_MM_FOLIO_NEXT_H
+#define _LINUX_MM_FOLIO_NEXT_H
+
+#include <linux/mm/folio_size.h> // for folio_nr_pages()
+#include <linux/mm/page_address.h> // for nth_page(), needed by folio_page()
+
+/**
+ * folio_next - Move to the next physical folio.
+ * @folio: The folio we're currently operating on.
+ *
+ * If you have physically contiguous memory which may span more than
+ * one folio (eg a &struct bio_vec), use this function to move from one
+ * folio to the next.  Do not use it if the memory is only virtually
+ * contiguous as the folios are almost certainly not adjacent to each
+ * other.  This is the folio equivalent to writing ``page++``.
+ *
+ * Context: We assume that the folios are refcounted and/or locked at a
+ * higher level and do not adjust the reference counts.
+ * Return: The next struct folio.
+ */
+static inline struct folio *folio_next(struct folio *folio)
+{
+	return (struct folio *)folio_page(folio, folio_nr_pages(folio));
+}
+
+#endif /* _LINUX_MM_FOLIO_NEXT_H */
-- 
2.39.2

[PATCH v2 08/14] linux/mm.h: move devmap-related declarations to mm/devmap_managed.h

[Max Kellermann]

Prepare to reduce dependencies on linux/mm.h.

put_devmap_managed_page() is called by put_page().  Moving it to a
separate header allows us to move put_page() to a separate lean header
as well.

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
---
 include/linux/mm.h                | 24 --------------------
 include/linux/mm/devmap_managed.h | 37 +++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 24 deletions(-)
 create mode 100644 include/linux/mm/devmap_managed.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 7d83d6d64f30..7a302da7de24 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1350,30 +1350,6 @@ vm_fault_t finish_fault(struct vm_fault *vmf);
  *   back into memory.
  */
 
-#if defined(CONFIG_ZONE_DEVICE) && defined(CONFIG_FS_DAX)
-DECLARE_STATIC_KEY_FALSE(devmap_managed_key);
-
-bool __put_devmap_managed_page_refs(struct page *page, int refs);
-static inline bool put_devmap_managed_page_refs(struct page *page, int refs)
-{
-	if (!static_branch_unlikely(&devmap_managed_key))
-		return false;
-	if (!is_zone_device_page(page))
-		return false;
-	return __put_devmap_managed_page_refs(page, refs);
-}
-#else /* CONFIG_ZONE_DEVICE && CONFIG_FS_DAX */
-static inline bool put_devmap_managed_page_refs(struct page *page, int refs)
-{
-	return false;
-}
-#endif /* CONFIG_ZONE_DEVICE && CONFIG_FS_DAX */
-
-static inline bool put_devmap_managed_page(struct page *page)
-{
-	return put_devmap_managed_page_refs(page, 1);
-}
-
 /* 127: arbitrary random number, small enough to assemble well */
 #define folio_ref_zero_or_close_to_overflow(folio) \
 	((unsigned int) folio_ref_count(folio) + 127u <= 127u)
diff --git a/include/linux/mm/devmap_managed.h b/include/linux/mm/devmap_managed.h
new file mode 100644
index 000000000000..0773529d80b2
--- /dev/null
+++ b/include/linux/mm/devmap_managed.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_MM_DEVMAP_MANAGED_H
+#define _LINUX_MM_DEVMAP_MANAGED_H
+
+#include <linux/types.h> // for bool
+
+struct page;
+
+#if defined(CONFIG_ZONE_DEVICE) && defined(CONFIG_FS_DAX)
+
+#include <linux/jump_label.h> // for DECLARE_STATIC_KEY_FALSE(), static_branch_unlikely()
+#include <linux/mmzone.h> // is_zone_device_page()
+
+DECLARE_STATIC_KEY_FALSE(devmap_managed_key);
+
+bool __put_devmap_managed_page_refs(struct page *page, int refs);
+static inline bool put_devmap_managed_page_refs(struct page *page, int refs)
+{
+	if (!static_branch_unlikely(&devmap_managed_key))
+		return false;
+	if (!is_zone_device_page(page))
+		return false;
+	return __put_devmap_managed_page_refs(page, refs);
+}
+#else /* CONFIG_ZONE_DEVICE && CONFIG_FS_DAX */
+static inline bool put_devmap_managed_page_refs(struct page *page, int refs)
+{
+	return false;
+}
+#endif /* CONFIG_ZONE_DEVICE && CONFIG_FS_DAX */
+
+static inline bool put_devmap_managed_page(struct page *page)
+{
+	return put_devmap_managed_page_refs(page, 1);
+}
+
+#endif /* _LINUX_MM_DEVMAP_MANAGED_H */
-- 
2.39.2

[PATCH v2 09/14] linux/mm.h: move usage count functions to mm/folio_usage.h

[Max Kellermann]

Prepare to reduce dependencies on linux/mm.h.

This new header contains wrappers for the low-level functions from
page_ref.h.  By having those higher-level functions in a separate
header, we can avoid their additional dependencies in the page_ref.h.

Having these in a separate header will allow eliminating the
dependency on linux/mm.h from these headers:

- linux/skbuff.h
- linux/swap.h

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
---
 include/linux/mm.h             | 168 +------------------------------
 include/linux/mm/folio_usage.h | 177 +++++++++++++++++++++++++++++++++
 2 files changed, 178 insertions(+), 167 deletions(-)
 create mode 100644 include/linux/mm/folio_usage.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 7a302da7de24..0dc38017e134 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -4,6 +4,7 @@
 
 #include <linux/mm/folio_next.h>
 #include <linux/mm/folio_size.h>
+#include <linux/mm/folio_usage.h>
 #include <linux/mm/page_address.h>
 #include <linux/mm/page_section.h>
 #include <linux/errno.h>
@@ -1058,51 +1059,6 @@ struct inode;
 
 #include <linux/huge_mm.h>
 
-/*
- * Methods to modify the page usage count.
- *
- * What counts for a page usage:
- * - cache mapping   (page->mapping)
- * - private data    (page->private)
- * - page mapped in a task's page tables, each mapping
- *   is counted separately
- *
- * Also, many kernel routines increase the page count before a critical
- * routine so they can be sure the page doesn't go away from under them.
- */
-
-/*
- * Drop a ref, return true if the refcount fell to zero (the page has no users)
- */
-static inline int put_page_testzero(struct page *page)
-{
-	VM_BUG_ON_PAGE(page_ref_count(page) == 0, page);
-	return page_ref_dec_and_test(page);
-}
-
-static inline int folio_put_testzero(struct folio *folio)
-{
-	return put_page_testzero(&folio->page);
-}
-
-/*
- * Try to grab a ref unless the page has a refcount of zero, return false if
- * that is the case.
- * This can be called when MMU is off so it must not access
- * any of the virtual mappings.
- */
-static inline bool get_page_unless_zero(struct page *page)
-{
-	return page_ref_add_unless(page, 1, 0);
-}
-
-static inline struct folio *folio_get_nontail_page(struct page *page)
-{
-	if (unlikely(!get_page_unless_zero(page)))
-		return NULL;
-	return (struct folio *)page;
-}
-
 extern int page_is_ram(unsigned long pfn);
 
 enum {
@@ -1258,8 +1214,6 @@ static inline struct folio *virt_to_folio(const void *x)
 	return page_folio(page);
 }
 
-void __folio_put(struct folio *folio);
-
 void put_pages_list(struct list_head *pages);
 
 void split_page(struct page *page, unsigned int order);
@@ -1350,126 +1304,6 @@ vm_fault_t finish_fault(struct vm_fault *vmf);
  *   back into memory.
  */
 
-/* 127: arbitrary random number, small enough to assemble well */
-#define folio_ref_zero_or_close_to_overflow(folio) \
-	((unsigned int) folio_ref_count(folio) + 127u <= 127u)
-
-/**
- * folio_get - Increment the reference count on a folio.
- * @folio: The folio.
- *
- * Context: May be called in any context, as long as you know that
- * you have a refcount on the folio.  If you do not already have one,
- * folio_try_get() may be the right interface for you to use.
- */
-static inline void folio_get(struct folio *folio)
-{
-	VM_BUG_ON_FOLIO(folio_ref_zero_or_close_to_overflow(folio), folio);
-	folio_ref_inc(folio);
-}
-
-static inline void get_page(struct page *page)
-{
-	folio_get(page_folio(page));
-}
-
-static inline __must_check bool try_get_page(struct page *page)
-{
-	page = compound_head(page);
-	if (WARN_ON_ONCE(page_ref_count(page) <= 0))
-		return false;
-	page_ref_inc(page);
-	return true;
-}
-
-/**
- * folio_put - Decrement the reference count on a folio.
- * @folio: The folio.
- *
- * If the folio's reference count reaches zero, the memory will be
- * released back to the page allocator and may be used by another
- * allocation immediately.  Do not access the memory or the struct folio
- * after calling folio_put() unless you can be sure that it wasn't the
- * last reference.
- *
- * Context: May be called in process or interrupt context, but not in NMI
- * context.  May be called while holding a spinlock.
- */
-static inline void folio_put(struct folio *folio)
-{
-	if (folio_put_testzero(folio))
-		__folio_put(folio);
-}
-
-/**
- * folio_put_refs - Reduce the reference count on a folio.
- * @folio: The folio.
- * @refs: The amount to subtract from the folio's reference count.
- *
- * If the folio's reference count reaches zero, the memory will be
- * released back to the page allocator and may be used by another
- * allocation immediately.  Do not access the memory or the struct folio
- * after calling folio_put_refs() unless you can be sure that these weren't
- * the last references.
- *
- * Context: May be called in process or interrupt context, but not in NMI
- * context.  May be called while holding a spinlock.
- */
-static inline void folio_put_refs(struct folio *folio, int refs)
-{
-	if (folio_ref_sub_and_test(folio, refs))
-		__folio_put(folio);
-}
-
-/*
- * union release_pages_arg - an array of pages or folios
- *
- * release_pages() releases a simple array of multiple pages, and
- * accepts various different forms of said page array: either
- * a regular old boring array of pages, an array of folios, or
- * an array of encoded page pointers.
- *
- * The transparent union syntax for this kind of "any of these
- * argument types" is all kinds of ugly, so look away.
- */
-typedef union {
-	struct page **pages;
-	struct folio **folios;
-	struct encoded_page **encoded_pages;
-} release_pages_arg __attribute__ ((__transparent_union__));
-
-void release_pages(release_pages_arg, int nr);
-
-/**
- * folios_put - Decrement the reference count on an array of folios.
- * @folios: The folios.
- * @nr: How many folios there are.
- *
- * Like folio_put(), but for an array of folios.  This is more efficient
- * than writing the loop yourself as it will optimise the locks which
- * need to be taken if the folios are freed.
- *
- * Context: May be called in process or interrupt context, but not in NMI
- * context.  May be called while holding a spinlock.
- */
-static inline void folios_put(struct folio **folios, unsigned int nr)
-{
-	release_pages(folios, nr);
-}
-
-static inline void put_page(struct page *page)
-{
-	struct folio *folio = page_folio(page);
-
-	/*
-	 * For some devmap managed pages we need to catch refcount transition
-	 * from 2 to 1:
-	 */
-	if (put_devmap_managed_page(&folio->page))
-		return;
-	folio_put(folio);
-}
-
 /*
  * GUP_PIN_COUNTING_BIAS, and the associated functions that use it, overload
  * the page's refcount so that two separate items are tracked: the original page
diff --git a/include/linux/mm/folio_usage.h b/include/linux/mm/folio_usage.h
new file mode 100644
index 000000000000..2700e2ec4d78
--- /dev/null
+++ b/include/linux/mm/folio_usage.h
@@ -0,0 +1,177 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_MM_FOLIO_USAGE_H
+#define _LINUX_MM_FOLIO_USAGE_H
+
+#include <linux/mm/devmap_managed.h> // for put_devmap_managed_page()
+#include <linux/mmdebug.h> // for VM_BUG_ON_PAGE()
+#include <linux/mm_types.h> // for struct folio
+#include <linux/page_ref.h>
+
+/*
+ * Methods to modify the page usage count.
+ *
+ * What counts for a page usage:
+ * - cache mapping   (page->mapping)
+ * - private data    (page->private)
+ * - page mapped in a task's page tables, each mapping
+ *   is counted separately
+ *
+ * Also, many kernel routines increase the page count before a critical
+ * routine so they can be sure the page doesn't go away from under them.
+ */
+
+/*
+ * Drop a ref, return true if the refcount fell to zero (the page has no users)
+ */
+static inline int put_page_testzero(struct page *page)
+{
+	VM_BUG_ON_PAGE(page_ref_count(page) == 0, page);
+	return page_ref_dec_and_test(page);
+}
+
+static inline int folio_put_testzero(struct folio *folio)
+{
+	return put_page_testzero(&folio->page);
+}
+
+/*
+ * Try to grab a ref unless the page has a refcount of zero, return false if
+ * that is the case.
+ * This can be called when MMU is off so it must not access
+ * any of the virtual mappings.
+ */
+static inline bool get_page_unless_zero(struct page *page)
+{
+	return page_ref_add_unless(page, 1, 0);
+}
+
+static inline struct folio *folio_get_nontail_page(struct page *page)
+{
+	if (unlikely(!get_page_unless_zero(page)))
+		return NULL;
+	return (struct folio *)page;
+}
+
+void __folio_put(struct folio *folio);
+
+/* 127: arbitrary random number, small enough to assemble well */
+#define folio_ref_zero_or_close_to_overflow(folio) \
+	((unsigned int) folio_ref_count(folio) + 127u <= 127u)
+
+/**
+ * folio_get - Increment the reference count on a folio.
+ * @folio: The folio.
+ *
+ * Context: May be called in any context, as long as you know that
+ * you have a refcount on the folio.  If you do not already have one,
+ * folio_try_get() may be the right interface for you to use.
+ */
+static inline void folio_get(struct folio *folio)
+{
+	VM_BUG_ON_FOLIO(folio_ref_zero_or_close_to_overflow(folio), folio);
+	folio_ref_inc(folio);
+}
+
+static inline void get_page(struct page *page)
+{
+	folio_get(page_folio(page));
+}
+
+static inline __must_check bool try_get_page(struct page *page)
+{
+	page = compound_head(page);
+	if (WARN_ON_ONCE(page_ref_count(page) <= 0))
+		return false;
+	page_ref_inc(page);
+	return true;
+}
+
+/**
+ * folio_put - Decrement the reference count on a folio.
+ * @folio: The folio.
+ *
+ * If the folio's reference count reaches zero, the memory will be
+ * released back to the page allocator and may be used by another
+ * allocation immediately.  Do not access the memory or the struct folio
+ * after calling folio_put() unless you can be sure that it wasn't the
+ * last reference.
+ *
+ * Context: May be called in process or interrupt context, but not in NMI
+ * context.  May be called while holding a spinlock.
+ */
+static inline void folio_put(struct folio *folio)
+{
+	if (folio_put_testzero(folio))
+		__folio_put(folio);
+}
+
+/**
+ * folio_put_refs - Reduce the reference count on a folio.
+ * @folio: The folio.
+ * @refs: The amount to subtract from the folio's reference count.
+ *
+ * If the folio's reference count reaches zero, the memory will be
+ * released back to the page allocator and may be used by another
+ * allocation immediately.  Do not access the memory or the struct folio
+ * after calling folio_put_refs() unless you can be sure that these weren't
+ * the last references.
+ *
+ * Context: May be called in process or interrupt context, but not in NMI
+ * context.  May be called while holding a spinlock.
+ */
+static inline void folio_put_refs(struct folio *folio, int refs)
+{
+	if (folio_ref_sub_and_test(folio, refs))
+		__folio_put(folio);
+}
+
+/*
+ * union release_pages_arg - an array of pages or folios
+ *
+ * release_pages() releases a simple array of multiple pages, and
+ * accepts various different forms of said page array: either
+ * a regular old boring array of pages, an array of folios, or
+ * an array of encoded page pointers.
+ *
+ * The transparent union syntax for this kind of "any of these
+ * argument types" is all kinds of ugly, so look away.
+ */
+typedef union {
+	struct page **pages;
+	struct folio **folios;
+	struct encoded_page **encoded_pages;
+} release_pages_arg __attribute__ ((__transparent_union__));
+
+void release_pages(release_pages_arg, int nr);
+
+/**
+ * folios_put - Decrement the reference count on an array of folios.
+ * @folios: The folios.
+ * @nr: How many folios there are.
+ *
+ * Like folio_put(), but for an array of folios.  This is more efficient
+ * than writing the loop yourself as it will optimise the locks which
+ * need to be taken if the folios are freed.
+ *
+ * Context: May be called in process or interrupt context, but not in NMI
+ * context.  May be called while holding a spinlock.
+ */
+static inline void folios_put(struct folio **folios, unsigned int nr)
+{
+	release_pages(folios, nr);
+}
+
+static inline void put_page(struct page *page)
+{
+	struct folio *folio = page_folio(page);
+
+	/*
+	 * For some devmap managed pages we need to catch refcount transition
+	 * from 2 to 1:
+	 */
+	if (put_devmap_managed_page(&folio->page))
+		return;
+	folio_put(folio);
+}
+
+#endif /* _LINUX_MM_FOLIO_USAGE_H */
-- 
2.39.2

[PATCH v2 10/14] linux/mm.h: move page_zone_id() and more to mm/folio_zone.h

[Max Kellermann]

This is needed to eliminate linux/skbuff.h's dependency on linux/mm.h.

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
---
 include/linux/mm.h            | 30 +--------------------------
 include/linux/mm/folio_zone.h | 38 +++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 29 deletions(-)
 create mode 100644 include/linux/mm/folio_zone.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0dc38017e134..1297ae7b2541 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -5,6 +5,7 @@
 #include <linux/mm/folio_next.h>
 #include <linux/mm/folio_size.h>
 #include <linux/mm/folio_usage.h>
+#include <linux/mm/folio_zone.h>
 #include <linux/mm/page_address.h>
 #include <linux/mm/page_section.h>
 #include <linux/errno.h>
@@ -1363,35 +1364,6 @@ static inline bool is_nommu_shared_mapping(vm_flags_t flags)
 }
 #endif
 
-/*
- * The identification function is mainly used by the buddy allocator for
- * determining if two pages could be buddies. We are not really identifying
- * the zone since we could be using the section number id if we do not have
- * node id available in page flags.
- * We only guarantee that it will return the same value for two combinable
- * pages in a zone.
- */
-static inline int page_zone_id(struct page *page)
-{
-	return (page->flags >> ZONEID_PGSHIFT) & ZONEID_MASK;
-}
-
-#ifdef NODE_NOT_IN_PAGE_FLAGS
-extern int page_to_nid(const struct page *page);
-#else
-static inline int page_to_nid(const struct page *page)
-{
-	struct page *p = (struct page *)page;
-
-	return (PF_POISONED_CHECK(p)->flags >> NODES_PGSHIFT) & NODES_MASK;
-}
-#endif
-
-static inline int folio_nid(const struct folio *folio)
-{
-	return page_to_nid(&folio->page);
-}
-
 #ifdef CONFIG_NUMA_BALANCING
 /* page access time bits needs to hold at least 4 seconds */
 #define PAGE_ACCESS_TIME_MIN_BITS	12
diff --git a/include/linux/mm/folio_zone.h b/include/linux/mm/folio_zone.h
new file mode 100644
index 000000000000..8ebcdb57ee2d
--- /dev/null
+++ b/include/linux/mm/folio_zone.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_MM_FOLIO_ZONE_H
+#define _LINUX_MM_FOLIO_ZONE_H
+
+#include <linux/mm_types.h> // for struct page, struct folio
+#include <linux/mmzone.h> // for ZONEID_*, NODES_*
+#include <linux/page-flags.h> // for PF_POISONED_CHECK()
+
+/*
+ * The identification function is mainly used by the buddy allocator for
+ * determining if two pages could be buddies. We are not really identifying
+ * the zone since we could be using the section number id if we do not have
+ * node id available in page flags.
+ * We only guarantee that it will return the same value for two combinable
+ * pages in a zone.
+ */
+static inline int page_zone_id(struct page *page)
+{
+	return (page->flags >> ZONEID_PGSHIFT) & ZONEID_MASK;
+}
+
+#ifdef NODE_NOT_IN_PAGE_FLAGS
+extern int page_to_nid(const struct page *page);
+#else
+static inline int page_to_nid(const struct page *page)
+{
+	struct page *p = (struct page *)page;
+
+	return (PF_POISONED_CHECK(p)->flags >> NODES_PGSHIFT) & NODES_MASK;
+}
+#endif
+
+static inline int folio_nid(const struct folio *folio)
+{
+	return page_to_nid(&folio->page);
+}
+
+#endif /* _LINUX_MM_FOLIO_ZONE_H */
-- 
2.39.2

[PATCH v2 11/14] linux/mm.h: move pfmemalloc-related functions to pfmemalloc.h

[Max Kellermann]

This is needed to eliminate linux/skbuff.h's dependency on linux/mm.h.

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
---
 include/linux/mm.h            | 45 +-----------------------------
 include/linux/mm/pfmemalloc.h | 52 +++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 44 deletions(-)
 create mode 100644 include/linux/mm/pfmemalloc.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1297ae7b2541..68228f43e7ca 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -8,6 +8,7 @@
 #include <linux/mm/folio_zone.h>
 #include <linux/mm/page_address.h>
 #include <linux/mm/page_section.h>
+#include <linux/mm/pfmemalloc.h>
 #include <linux/errno.h>
 #include <linux/mmdebug.h>
 #include <linux/gfp.h>
@@ -1749,50 +1750,6 @@ static inline pgoff_t page_index(struct page *page)
 	return page->index;
 }
 
-/*
- * Return true only if the page has been allocated with
- * ALLOC_NO_WATERMARKS and the low watermark was not
- * met implying that the system is under some pressure.
- */
-static inline bool page_is_pfmemalloc(const struct page *page)
-{
-	/*
-	 * lru.next has bit 1 set if the page is allocated from the
-	 * pfmemalloc reserves.  Callers may simply overwrite it if
-	 * they do not need to preserve that information.
-	 */
-	return (uintptr_t)page->lru.next & BIT(1);
-}
-
-/*
- * Return true only if the folio has been allocated with
- * ALLOC_NO_WATERMARKS and the low watermark was not
- * met implying that the system is under some pressure.
- */
-static inline bool folio_is_pfmemalloc(const struct folio *folio)
-{
-	/*
-	 * lru.next has bit 1 set if the page is allocated from the
-	 * pfmemalloc reserves.  Callers may simply overwrite it if
-	 * they do not need to preserve that information.
-	 */
-	return (uintptr_t)folio->lru.next & BIT(1);
-}
-
-/*
- * Only to be called by the page allocator on a freshly allocated
- * page.
- */
-static inline void set_page_pfmemalloc(struct page *page)
-{
-	page->lru.next = (void *)BIT(1);
-}
-
-static inline void clear_page_pfmemalloc(struct page *page)
-{
-	page->lru.next = NULL;
-}
-
 /*
  * Can be called by the pagefault handler when it gets a VM_FAULT_OOM.
  */
diff --git a/include/linux/mm/pfmemalloc.h b/include/linux/mm/pfmemalloc.h
new file mode 100644
index 000000000000..345b215a3566
--- /dev/null
+++ b/include/linux/mm/pfmemalloc.h
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_MM_PFMEMALLOC_H
+#define _LINUX_MM_PFMEMALLOC_H
+
+#include <linux/bits.h> // for BIT()
+#include <linux/mm_types.h> // for struct page
+
+/*
+ * Return true only if the page has been allocated with
+ * ALLOC_NO_WATERMARKS and the low watermark was not
+ * met implying that the system is under some pressure.
+ */
+static inline bool page_is_pfmemalloc(const struct page *page)
+{
+	/*
+	 * lru.next has bit 1 set if the page is allocated from the
+	 * pfmemalloc reserves.  Callers may simply overwrite it if
+	 * they do not need to preserve that information.
+	 */
+	return (uintptr_t)page->lru.next & BIT(1);
+}
+
+/*
+ * Return true only if the folio has been allocated with
+ * ALLOC_NO_WATERMARKS and the low watermark was not
+ * met implying that the system is under some pressure.
+ */
+static inline bool folio_is_pfmemalloc(const struct folio *folio)
+{
+	/*
+	 * lru.next has bit 1 set if the page is allocated from the
+	 * pfmemalloc reserves.  Callers may simply overwrite it if
+	 * they do not need to preserve that information.
+	 */
+	return (uintptr_t)folio->lru.next & BIT(1);
+}
+
+/*
+ * Only to be called by the page allocator on a freshly allocated
+ * page.
+ */
+static inline void set_page_pfmemalloc(struct page *page)
+{
+	page->lru.next = (void *)BIT(1);
+}
+
+static inline void clear_page_pfmemalloc(struct page *page)
+{
+	page->lru.next = NULL;
+}
+
+#endif /* _LINUX_MM_PFMEMALLOC_H */
-- 
2.39.2

[PATCH v2 12/14] linux/mm.h: move is_vmalloc_addr() to mm/vmalloc_addr.h

[Max Kellermann]

This is needed to eliminate linux/dma-mapping.h's dependency on
linux/mm.h.

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
---
 include/linux/mm.h              | 25 +------------------------
 include/linux/mm/vmalloc_addr.h | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 24 deletions(-)
 create mode 100644 include/linux/mm/vmalloc_addr.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 68228f43e7ca..ad5971219ef6 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -9,6 +9,7 @@
 #include <linux/mm/page_address.h>
 #include <linux/mm/page_section.h>
 #include <linux/mm/pfmemalloc.h>
+#include <linux/mm/vmalloc_addr.h>
 #include <linux/errno.h>
 #include <linux/mmdebug.h>
 #include <linux/gfp.h>
@@ -1072,30 +1073,6 @@ enum {
 int region_intersects(resource_size_t offset, size_t size, unsigned long flags,
 		      unsigned long desc);
 
-/* Support for virtually mapped pages */
-struct page *vmalloc_to_page(const void *addr);
-unsigned long vmalloc_to_pfn(const void *addr);
-
-/*
- * Determine if an address is within the vmalloc range
- *
- * On nommu, vmalloc/vfree wrap through kmalloc/kfree directly, so there
- * is no special casing required.
- */
-#ifdef CONFIG_MMU
-extern bool is_vmalloc_addr(const void *x);
-extern int is_vmalloc_or_module_addr(const void *x);
-#else
-static inline bool is_vmalloc_addr(const void *x)
-{
-	return false;
-}
-static inline int is_vmalloc_or_module_addr(const void *x)
-{
-	return 0;
-}
-#endif
-
 /*
  * How many times the entire folio is mapped as a single unit (eg by a
  * PMD or PUD entry).  This is probably not what you want, except for
diff --git a/include/linux/mm/vmalloc_addr.h b/include/linux/mm/vmalloc_addr.h
new file mode 100644
index 000000000000..86ad2dc94960
--- /dev/null
+++ b/include/linux/mm/vmalloc_addr.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_MM_VMALLOC_ADDR_H
+#define _LINUX_MM_VMALLOC_ADDR_H
+
+#include <linux/types.h> // for bool
+
+struct page;
+
+/* Support for virtually mapped pages */
+struct page *vmalloc_to_page(const void *addr);
+unsigned long vmalloc_to_pfn(const void *addr);
+
+/*
+ * Determine if an address is within the vmalloc range
+ *
+ * On nommu, vmalloc/vfree wrap through kmalloc/kfree directly, so there
+ * is no special casing required.
+ */
+#ifdef CONFIG_MMU
+extern bool is_vmalloc_addr(const void *x);
+extern int is_vmalloc_or_module_addr(const void *x);
+#else
+static inline bool is_vmalloc_addr(const void *x)
+{
+	return false;
+}
+static inline int is_vmalloc_or_module_addr(const void *x)
+{
+	return 0;
+}
+#endif
+
+#endif /* _LINUX_MM_VMALLOC_ADDR_H */
-- 
2.39.2

[PATCH v2 13/14] linux/mm.h: move high_memory to mm/high_memory.h

[Max Kellermann]

This variable is used by lots of arch/*/include/asm/ headers, but
these do not (and should not) include the huge linux/mm.h header.
Let's move this "extern" variable to a separate header and include
this one in arch/.

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
---
 arch/arm/include/asm/memory.h                | 4 ++++
 arch/arm/include/asm/pgtable.h               | 2 ++
 arch/csky/include/asm/page.h                 | 1 +
 arch/hexagon/include/asm/mem-layout.h        | 4 ++++
 arch/m68k/include/asm/page_mm.h              | 1 +
 arch/m68k/include/asm/pgtable_mm.h           | 1 +
 arch/parisc/include/asm/floppy.h             | 1 +
 arch/powerpc/include/asm/book3s/32/pgtable.h | 4 ++++
 arch/powerpc/include/asm/nohash/32/pgtable.h | 1 +
 arch/powerpc/include/asm/page.h              | 1 +
 arch/x86/include/asm/floppy.h                | 1 +
 arch/x86/include/asm/pgtable_32_areas.h      | 4 ++++
 drivers/mtd/nand/onenand/onenand_samsung.c   | 1 +
 include/linux/mm.h                           | 2 +-
 include/linux/mm/high_memory.h               | 7 +++++++
 15 files changed, 34 insertions(+), 1 deletion(-)
 create mode 100644 include/linux/mm/high_memory.h

diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index ef2aa79ece5a..a67afb213e2e 100644
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -387,6 +387,10 @@ static inline unsigned long __virt_to_idmap(unsigned long x)
  */
 #define ARCH_PFN_OFFSET		PHYS_PFN_OFFSET
 
+#ifndef __ASSEMBLY__
+#include <linux/mm/high_memory.h>
+#endif
+
 #define virt_to_page(kaddr)	pfn_to_page(virt_to_pfn(kaddr))
 #define virt_addr_valid(kaddr)	(((unsigned long)(kaddr) >= PAGE_OFFSET && (unsigned long)(kaddr) < (unsigned long)high_memory) \
 					&& pfn_valid(virt_to_pfn(kaddr)))
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index be91e376df79..eb80f6a65619 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -11,6 +11,8 @@
 #include <asm/proc-fns.h>
 
 #ifndef __ASSEMBLY__
+#include <linux/mm/high_memory.h>
+
 /*
  * ZERO_PAGE is a global shared page that is always zero: used
  * for zero-mapped memory areas etc..
diff --git a/arch/csky/include/asm/page.h b/arch/csky/include/asm/page.h
index 4a0502e324a6..016f722fbe43 100644
--- a/arch/csky/include/asm/page.h
+++ b/arch/csky/include/asm/page.h
@@ -32,6 +32,7 @@
 
 #ifndef __ASSEMBLY__
 
+#include <linux/mm/high_memory.h>
 #include <linux/pfn.h>
 
 #define virt_addr_valid(kaddr)  ((void *)(kaddr) >= (void *)PAGE_OFFSET && \
diff --git a/arch/hexagon/include/asm/mem-layout.h b/arch/hexagon/include/asm/mem-layout.h
index e2f99413fe56..a09116c50043 100644
--- a/arch/hexagon/include/asm/mem-layout.h
+++ b/arch/hexagon/include/asm/mem-layout.h
@@ -10,6 +10,10 @@
 
 #include <linux/const.h>
 
+#ifndef __ASSEMBLY__
+#include <linux/mm/high_memory.h>
+#endif
+
 /*
  * Have to do this for ginormous numbers, else they get printed as
  * negative numbers, which the linker no likey when you try to
diff --git a/arch/m68k/include/asm/page_mm.h b/arch/m68k/include/asm/page_mm.h
index e0ae4d5fc985..f958655d1931 100644
--- a/arch/m68k/include/asm/page_mm.h
+++ b/arch/m68k/include/asm/page_mm.h
@@ -5,6 +5,7 @@
 #ifndef __ASSEMBLY__
 
 #include <linux/compiler.h>
+#include <linux/mm/high_memory.h>
 #include <asm/module.h>
 
 /*
diff --git a/arch/m68k/include/asm/pgtable_mm.h b/arch/m68k/include/asm/pgtable_mm.h
index dbdf1c2b2f66..ec593656bdc5 100644
--- a/arch/m68k/include/asm/pgtable_mm.h
+++ b/arch/m68k/include/asm/pgtable_mm.h
@@ -13,6 +13,7 @@
 
 #ifndef __ASSEMBLY__
 #include <asm/processor.h>
+#include <linux/mm/high_memory.h>
 #include <linux/sched.h>
 #include <linux/threads.h>
 
diff --git a/arch/parisc/include/asm/floppy.h b/arch/parisc/include/asm/floppy.h
index b318a7df52f6..98ed37c5dc59 100644
--- a/arch/parisc/include/asm/floppy.h
+++ b/arch/parisc/include/asm/floppy.h
@@ -8,6 +8,7 @@
 #ifndef __ASM_PARISC_FLOPPY_H
 #define __ASM_PARISC_FLOPPY_H
 
+#include <linux/mm/high_memory.h>
 #include <linux/vmalloc.h>
 
 
diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h
index 52971ee30717..03e0a32e1c2c 100644
--- a/arch/powerpc/include/asm/book3s/32/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/32/pgtable.h
@@ -4,6 +4,10 @@
 
 #include <asm-generic/pgtable-nopmd.h>
 
+#ifndef __ASSEMBLY__
+#include <linux/mm/high_memory.h>
+#endif
+
 /*
  * The "classic" 32-bit implementation of the PowerPC MMU uses a hash
  * table containing PTEs, together with a set of 16 segment registers,
diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h b/arch/powerpc/include/asm/nohash/32/pgtable.h
index 9164a9e41b02..8a9f5b546e4a 100644
--- a/arch/powerpc/include/asm/nohash/32/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/32/pgtable.h
@@ -5,6 +5,7 @@
 #include <asm-generic/pgtable-nopmd.h>
 
 #ifndef __ASSEMBLY__
+#include <linux/mm/high_memory.h>
 #include <linux/sched.h>
 #include <linux/threads.h>
 #include <asm/mmu.h>			/* For sub-arch specific PPC_PIN_SIZE */
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index e5fcc79b5bfb..c541e71d3d5c 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -7,6 +7,7 @@
  */
 
 #ifndef __ASSEMBLY__
+#include <linux/mm/high_memory.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/bug.h>
diff --git a/arch/x86/include/asm/floppy.h b/arch/x86/include/asm/floppy.h
index 6ec3fc969ad5..7756e984f146 100644
--- a/arch/x86/include/asm/floppy.h
+++ b/arch/x86/include/asm/floppy.h
@@ -10,6 +10,7 @@
 #ifndef _ASM_X86_FLOPPY_H
 #define _ASM_X86_FLOPPY_H
 
+#include <linux/mm/high_memory.h>
 #include <linux/vmalloc.h>
 
 /*
diff --git a/arch/x86/include/asm/pgtable_32_areas.h b/arch/x86/include/asm/pgtable_32_areas.h
index b6355416a15a..b339137b4f4e 100644
--- a/arch/x86/include/asm/pgtable_32_areas.h
+++ b/arch/x86/include/asm/pgtable_32_areas.h
@@ -3,6 +3,10 @@
 
 #include <asm/cpu_entry_area.h>
 
+#ifndef __ASSEMBLY__
+#include <linux/mm/high_memory.h>
+#endif
+
 /*
  * Just any arbitrary offset to the start of the vmalloc VM area: the
  * current 8MB value just means that there will be a 8MB "hole" after the
diff --git a/drivers/mtd/nand/onenand/onenand_samsung.c b/drivers/mtd/nand/onenand/onenand_samsung.c
index fd6890a03d55..7c3cc270386d 100644
--- a/drivers/mtd/nand/onenand/onenand_samsung.c
+++ b/drivers/mtd/nand/onenand/onenand_samsung.c
@@ -15,6 +15,7 @@
 #include <linux/platform_device.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
+#include <linux/mm/high_memory.h>
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/onenand.h>
 #include <linux/mtd/partitions.h>
diff --git a/include/linux/mm.h b/include/linux/mm.h
index ad5971219ef6..b5cfe35ee7f2 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -6,6 +6,7 @@
 #include <linux/mm/folio_size.h>
 #include <linux/mm/folio_usage.h>
 #include <linux/mm/folio_zone.h>
+#include <linux/mm/high_memory.h>
 #include <linux/mm/page_address.h>
 #include <linux/mm/page_section.h>
 #include <linux/mm/pfmemalloc.h>
@@ -81,7 +82,6 @@ static inline void totalram_pages_add(long count)
 	atomic_long_add(count, &_totalram_pages);
 }
 
-extern void * high_memory;
 extern int page_cluster;
 extern const int page_cluster_max;
 
diff --git a/include/linux/mm/high_memory.h b/include/linux/mm/high_memory.h
new file mode 100644
index 000000000000..e504aafd0d48
--- /dev/null
+++ b/include/linux/mm/high_memory.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_MM_HIGH_MEMORY_H
+#define _LINUX_MM_HIGH_MEMORY_H
+
+extern void * high_memory;
+
+#endif /* _LINUX_MM_HIGH_MEMORY_H */
-- 
2.39.2

[PATCH v2 14/14] include: reduce dependencies on linux/mm.h

[Max Kellermann]

Replace <linux/mm.h> with the smaller pieces that were just splitted
out.  This affects a few headers that are included by many, e.g. bio.h
and highmem.h, which now no longer depend on the fat <linux/mm.h>
header.

For this, several missing includes need to be added because they are
no longer indirectly included, e.g. <linux/fs.h>.

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
---
 include/linux/bio.h              | 2 ++
 include/linux/dma-mapping.h      | 1 +
 include/linux/highmem-internal.h | 2 ++
 include/linux/highmem.h          | 4 +++-
 include/linux/scatterlist.h      | 2 +-
 include/linux/skbuff.h           | 4 ++++
 lib/scatterlist.c                | 1 +
 7 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 875d792bffff..e2f24d7235d3 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -5,7 +5,9 @@
 #ifndef __LINUX_BIO_H
 #define __LINUX_BIO_H
 
+#include <linux/fs.h> // for struct kiocb, IOCB_NOWAIT
 #include <linux/mempool.h>
+#include <linux/mm/folio_next.h>
 /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
 #include <linux/blk_types.h>
 #include <linux/uio.h>
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 4a658de44ee9..37d5591039c7 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -11,6 +11,7 @@
 #include <linux/scatterlist.h>
 #include <linux/bug.h>
 #include <linux/mem_encrypt.h>
+#include <linux/mm/vmalloc_addr.h>
 
 /**
  * List of possible attributes associated with a DMA mapping. The semantics
diff --git a/include/linux/highmem-internal.h b/include/linux/highmem-internal.h
index a3028e400a9c..a479e6b7c54c 100644
--- a/include/linux/highmem-internal.h
+++ b/include/linux/highmem-internal.h
@@ -2,6 +2,8 @@
 #ifndef _LINUX_HIGHMEM_INTERNAL_H
 #define _LINUX_HIGHMEM_INTERNAL_H
 
+#include <linux/mm/page_address.h>
+
 /*
  * Outside of CONFIG_HIGHMEM to support X86 32bit iomap_atomic() cruft.
  */
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index 00341b56d291..10a165a913ad 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -7,7 +7,9 @@
 #include <linux/bug.h>
 #include <linux/cacheflush.h>
 #include <linux/kmsan.h>
-#include <linux/mm.h>
+#include <linux/mm/folio_size.h> // for page_size()
+#include <linux/mm/folio_usage.h> // for folio_put()
+#include <linux/mm/page_address.h>
 #include <linux/uaccess.h>
 #include <linux/hardirq.h>
 
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 0516e64dc03e..9221bba82b23 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -5,7 +5,7 @@
 #include <linux/string.h>
 #include <linux/types.h>
 #include <linux/bug.h>
-#include <linux/mm.h>
+#include <linux/mm/page_address.h>
 #include <asm/io.h>
 
 #ifdef CONFIG_UML
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 28c7cb7ce251..06fedc08b998 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -16,6 +16,10 @@
 #include <linux/bug.h>
 #include <linux/bvec.h>
 #include <linux/cache.h>
+#include <linux/gfp.h> // for alloc_pages_node()
+#include <linux/mm/folio_usage.h> // for get_page(), put_page()
+#include <linux/mm/folio_zone.h> // for page_to_nid()
+#include <linux/mm/pfmemalloc.h> // for page_is_pfmemalloc()
 #include <linux/rbtree.h>
 #include <linux/socket.h>
 #include <linux/refcount.h>
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index 68b45c82c37a..03599396f15d 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -9,6 +9,7 @@
 #include <linux/scatterlist.h>
 #include <linux/highmem.h>
 #include <linux/kmemleak.h>
+#include <linux/mm.h>
 #include <linux/bvec.h>
 #include <linux/uio.h>
 
-- 
2.39.2