[PATCH v2 09/13] mm: update all remaining mmap_prepare users to use vma_flags_t

Lorenzo Stoakes
2026-01-22T16:08:09Z

We will be shortly removing the vm_flags_t field from vm_area_desc so we
need to update all mmap_prepare users to only use the dessc->vma_flags
field.

This patch achieves that and makes all ancillary changes required to make
this possible.

This lays the groundwork for future work to eliminate the use of vm_flags_t
in vm_area_desc altogether and more broadly throughout the kernel.

While we're here, we take the opportunity to replace VM_REMAP_FLAGS with
VMA_REMAP_FLAGS, the vma_flags_t equivalent.

No functional changes intended.

Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
---
drivers/char/mem.c | 6 +++---
drivers/dax/device.c | 10 +++++-----
fs/aio.c | 2 +-
fs/erofs/data.c | 5 +++--
fs/ext4/file.c | 4 ++--
fs/ntfs3/file.c | 2 +-
fs/orangefs/file.c | 4 ++--
fs/ramfs/file-nommu.c | 2 +-
fs/resctrl/pseudo_lock.c | 2 +-
fs/romfs/mmap-nommu.c | 2 +-
fs/xfs/xfs_file.c | 4 ++--
fs/zonefs/file.c | 3 ++-
include/linux/dax.h | 8 ++++----
include/linux/mm.h | 24 +++++++++++++++++++-----
kernel/relay.c | 2 +-
mm/memory.c | 17 ++++++++---------
16 files changed, 56 insertions(+), 41 deletions(-)

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 52039fae1594..cca4529431f8 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -306,7 +306,7 @@ static unsigned zero_mmap_capabilities(struct file *file)
/* can't do an in-place private mapping if there's no MMU */
static inline int private_mapping_ok(struct vm_area_desc *desc)
{
- return is_nommu_shared_mapping(desc->vm_flags);
+ return is_nommu_shared_vma_flags(&desc->vma_flags);
}
#else

@@ -360,7 +360,7 @@ static int mmap_mem_prepare(struct vm_area_desc *desc)

desc->vm_ops = &mmap_mem_ops;

- /* Remap-pfn-range will mark the range VM_IO. */
+ /* Remap-pfn-range will mark the range with the I/O flag. */
mmap_action_remap_full(desc, desc->pgoff);
/* We filter remap errors to -EAGAIN. */
desc->action.error_hook = mmap_filter_error;
@@ -520,7 +520,7 @@ static int mmap_zero_prepare(struct vm_area_desc *desc)
#ifndef CONFIG_MMU
return -ENOSYS;
#endif
- if (desc->vm_flags & VM_SHARED)
+ if (vma_desc_test_flags(desc, VMA_SHARED_BIT))
return shmem_zero_setup_desc(desc);

desc->action.success_hook = mmap_zero_private_success;
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 22999a402e02..528e81240c4d 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -13,7 +13,7 @@
#include "dax-private.h"
#include "bus.h"

-static int __check_vma(struct dev_dax *dev_dax, vm_flags_t vm_flags,
+static int __check_vma(struct dev_dax *dev_dax, vma_flags_t flags,
unsigned long start, unsigned long end, struct file *file,
const char *func)
{
@@ -24,7 +24,7 @@ static int __check_vma(struct dev_dax *dev_dax, vm_flags_t vm_flags,
return -ENXIO;

/* prevent private mappings from being established */
- if ((vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
+ if (!vma_flags_test(&flags, VMA_MAYSHARE_BIT)) {
dev_info_ratelimited(dev,
"%s: %s: fail, attempted private mapping\n",
current->comm, func);
@@ -53,7 +53,7 @@ static int __check_vma(struct dev_dax *dev_dax, vm_flags_t vm_flags,
static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
const char *func)
{
- return __check_vma(dev_dax, vma->vm_flags, vma->vm_start, vma->vm_end,
+ return __check_vma(dev_dax, vma->flags, vma->vm_start, vma->vm_end,
vma->vm_file, func);
}

@@ -306,14 +306,14 @@ static int dax_mmap_prepare(struct vm_area_desc *desc)
* fault time.
*/
id = dax_read_lock();
- rc = __check_vma(dev_dax, desc->vm_flags, desc->start, desc->end, filp,
+ rc = __check_vma(dev_dax, desc->vma_flags, desc->start, desc->end, filp,
__func__);
dax_read_unlock(id);
if (rc)
return rc;

desc->vm_ops = &dax_vm_ops;
- desc->vm_flags |= VM_HUGEPAGE;
+ vma_desc_set_flags(desc, VMA_HUGEPAGE_BIT);
return 0;
}

diff --git a/fs/aio.c b/fs/aio.c
index 0a23a8c0717f..59b67b8da1b2 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -394,7 +394,7 @@ static const struct vm_operations_struct aio_ring_vm_ops = {

static int aio_ring_mmap_prepare(struct vm_area_desc *desc)
{
- desc->vm_flags |= VM_DONTEXPAND;
+ vma_desc_set_flags(desc, VMA_DONTEXPAND_BIT);
desc->vm_ops = &aio_ring_vm_ops;
return 0;
}
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index bb13c4cb8455..e7bc29e764c6 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -438,11 +438,12 @@ static int erofs_file_mmap_prepare(struct vm_area_desc *desc)
if (!IS_DAX(file_inode(desc->file)))
return generic_file_readonly_mmap_prepare(desc);

- if ((desc->vm_flags & VM_SHARED) && (desc->vm_flags & VM_MAYWRITE))
+ if (vma_desc_test_flags(desc, VMA_SHARED_BIT) &&
+ vma_desc_test_flags(desc, VMA_MAYWRITE_BIT))
return -EINVAL;

desc->vm_ops = &erofs_dax_vm_ops;
- desc->vm_flags |= VM_HUGEPAGE;
+ vma_desc_set_flags(desc, VMA_HUGEPAGE_BIT);
return 0;
}
#else
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 7a8b30932189..dfd5f4fe1647 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -822,13 +822,13 @@ static int ext4_file_mmap_prepare(struct vm_area_desc *desc)
* We don't support synchronous mappings for non-DAX files and
* for DAX files if underneath dax_device is not synchronous.
*/
- if (!daxdev_mapping_supported(desc->vm_flags, file_inode(file), dax_dev))
+ if (!daxdev_mapping_supported(desc, file_inode(file), dax_dev))
return -EOPNOTSUPP;

file_accessed(file);
if (IS_DAX(file_inode(file))) {
desc->vm_ops = &ext4_dax_vm_ops;
- desc->vm_flags |= VM_HUGEPAGE;
+ vma_desc_set_flags(desc, VMA_HUGEPAGE_BIT);
} else {
desc->vm_ops = &ext4_file_vm_ops;
}
diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
index 2e7b2e566ebe..2902fc6d9a85 100644
--- a/fs/ntfs3/file.c
+++ b/fs/ntfs3/file.c
@@ -347,7 +347,7 @@ static int ntfs_file_mmap_prepare(struct vm_area_desc *desc)
struct inode *inode = file_inode(file);
struct ntfs_inode *ni = ntfs_i(inode);
u64 from = ((u64)desc->pgoff << PAGE_SHIFT);
- bool rw = desc->vm_flags & VM_WRITE;
+ const bool rw = vma_desc_test_flags(desc, VMA_WRITE_BIT);
int err;

/* Avoid any operation if inode is bad. */
diff --git a/fs/orangefs/file.c b/fs/orangefs/file.c
index 919f99b16834..c75aa3f419b1 100644
--- a/fs/orangefs/file.c
+++ b/fs/orangefs/file.c
@@ -411,8 +411,8 @@ static int orangefs_file_mmap_prepare(struct vm_area_desc *desc)
"orangefs_file_mmap: called on %pD\n", file);

/* set the sequential readahead hint */
- desc->vm_flags |= VM_SEQ_READ;
- desc->vm_flags &= ~VM_RAND_READ;
+ vma_desc_set_flags(desc, VMA_SEQ_READ_BIT);
+ vma_desc_clear_flags(desc, VMA_RAND_READ_BIT);

file_accessed(file);
desc->vm_ops = &orangefs_file_vm_ops;
diff --git a/fs/ramfs/file-nommu.c b/fs/ramfs/file-nommu.c
index 77b8ca2757e0..0f8e838ece07 100644
--- a/fs/ramfs/file-nommu.c
+++ b/fs/ramfs/file-nommu.c
@@ -264,7 +264,7 @@ static unsigned long ramfs_nommu_get_unmapped_area(struct file *file,
*/
static int ramfs_nommu_mmap_prepare(struct vm_area_desc *desc)
{
- if (!is_nommu_shared_mapping(desc->vm_flags))
+ if (!is_nommu_shared_vma_flags(&desc->vma_flags))
return -ENOSYS;

file_accessed(desc->file);
diff --git a/fs/resctrl/pseudo_lock.c b/fs/resctrl/pseudo_lock.c
index 0bfc13c5b96d..e81d71abfe54 100644
--- a/fs/resctrl/pseudo_lock.c
+++ b/fs/resctrl/pseudo_lock.c
@@ -1044,7 +1044,7 @@ static int pseudo_lock_dev_mmap_prepare(struct vm_area_desc *desc)
* Ensure changes are carried directly to the memory being mapped,
* do not allow copy-on-write mapping.
*/
- if (!(desc->vm_flags & VM_SHARED)) {
+ if (!vma_desc_test_flags(desc, VMA_SHARED_BIT)) {
mutex_unlock(&rdtgroup_mutex);
return -EINVAL;
}
diff --git a/fs/romfs/mmap-nommu.c b/fs/romfs/mmap-nommu.c
index 4b77c6dc4418..7c3a1a7fecee 100644
--- a/fs/romfs/mmap-nommu.c
+++ b/fs/romfs/mmap-nommu.c
@@ -63,7 +63,7 @@ static unsigned long romfs_get_unmapped_area(struct file *file,
*/
static int romfs_mmap_prepare(struct vm_area_desc *desc)
{
- return is_nommu_shared_mapping(desc->vm_flags) ? 0 : -ENOSYS;
+ return is_nommu_shared_vma_flags(&desc->vma_flags) ? 0 : -ENOSYS;
}

static unsigned romfs_mmap_capabilities(struct file *file)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 7874cf745af3..1238ec018bc7 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1974,14 +1974,14 @@ xfs_file_mmap_prepare(
* We don't support synchronous mappings for non-DAX files and
* for DAX files if underneath dax_device is not synchronous.
*/
- if (!daxdev_mapping_supported(desc->vm_flags, file_inode(file),
+ if (!daxdev_mapping_supported(desc, file_inode(file),
target->bt_daxdev))
return -EOPNOTSUPP;

file_accessed(file);
desc->vm_ops = &xfs_file_vm_ops;
if (IS_DAX(inode))
- desc->vm_flags |= VM_HUGEPAGE;
+ vma_desc_set_flags(desc, VMA_HUGEPAGE_BIT);
return 0;
}

diff --git a/fs/zonefs/file.c b/fs/zonefs/file.c
index c1e5e30e90a0..8a7161fc49e5 100644
--- a/fs/zonefs/file.c
+++ b/fs/zonefs/file.c
@@ -333,7 +333,8 @@ static int zonefs_file_mmap_prepare(struct vm_area_desc *desc)
* ordering between msync() and page cache writeback.
*/
if (zonefs_inode_is_seq(file_inode(file)) &&
- (desc->vm_flags & VM_SHARED) && (desc->vm_flags & VM_MAYWRITE))
+ vma_desc_test_flags(desc, VMA_SHARED_BIT) &&
+ vma_desc_test_flags(desc, VMA_MAYWRITE_BIT))
return -EINVAL;

file_accessed(file);
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 9d624f4d9df6..bf103f317cac 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -65,11 +65,11 @@ size_t dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
/*
* Check if given mapping is supported by the file / underlying device.
*/
-static inline bool daxdev_mapping_supported(vm_flags_t vm_flags,
+static inline bool daxdev_mapping_supported(const struct vm_area_desc *desc,
const struct inode *inode,
struct dax_device *dax_dev)
{
- if (!(vm_flags & VM_SYNC))
+ if (!vma_desc_test_flags(desc, VMA_SYNC_BIT))
return true;
if (!IS_DAX(inode))
return false;
@@ -111,11 +111,11 @@ static inline void set_dax_nomc(struct dax_device *dax_dev)
static inline void set_dax_synchronous(struct dax_device *dax_dev)
{
}
-static inline bool daxdev_mapping_supported(vm_flags_t vm_flags,
+static inline bool daxdev_mapping_supported(const struct vm_area_desc *desc,
const struct inode *inode,
struct dax_device *dax_dev)
{
- return !(vm_flags & VM_SYNC);
+ return !vma_desc_test_flags(desc, VMA_SYNC_BIT);
}
static inline size_t dax_recovery_write(struct dax_device *dax_dev,
pgoff_t pgoff, void *addr, size_t bytes, struct iov_iter *i)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index fd93317193e0..e31f72a021ef 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -550,17 +550,18 @@ enum {
/*
* Physically remapped pages are special. Tell the
* rest of the world about it:
- * VM_IO tells people not to look at these pages
+ * IO tells people not to look at these pages
* (accesses can have side effects).
- * VM_PFNMAP tells the core MM that the base pages are just
+ * PFNMAP tells the core MM that the base pages are just
* raw PFN mappings, and do not have a "struct page" associated
* with them.
- * VM_DONTEXPAND
+ * DONTEXPAND
* Disable vma merging and expanding with mremap().
- * VM_DONTDUMP
+ * DONTDUMP
* Omit vma from core dump, even when VM_IO turned off.
*/
-#define VM_REMAP_FLAGS (VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP)
+#define VMA_REMAP_FLAGS mk_vma_flags(VMA_IO_BIT, VMA_PFNMAP_BIT, \
+ VMA_DONTEXPAND_BIT, VMA_DONTDUMP_BIT)

/* This mask prevents VMA from being scanned with khugepaged */
#define VM_NO_KHUGEPAGED (VM_SPECIAL | VM_HUGETLB)
@@ -1925,6 +1926,14 @@ static inline bool is_cow_mapping(vm_flags_t flags)
return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
}

+static inline bool vma_desc_is_cow_mapping(struct vm_area_desc *desc)
+{
+ const vma_flags_t *flags = &desc->vma_flags;
+
+ return vma_flags_test(flags, VMA_MAYWRITE_BIT) &&
+ !vma_flags_test(flags, VMA_SHARED_BIT);
+}
+
#ifndef CONFIG_MMU
static inline bool is_nommu_shared_mapping(vm_flags_t flags)
{
@@ -1938,6 +1947,11 @@ static inline bool is_nommu_shared_mapping(vm_flags_t flags)
*/
return flags & (VM_MAYSHARE | VM_MAYOVERLAY);
}
+
+static inline bool is_nommu_shared_vma_flags(const vma_flags_t *flags)
+{
+ return vma_flags_test(flags, VMA_MAYSHARE_BIT, VMA_MAYOVERLAY_BIT);
+}
#endif

#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
diff --git a/kernel/relay.c b/kernel/relay.c
index e36f6b926f7f..1c8e88259df0 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -92,7 +92,7 @@ static int relay_mmap_prepare_buf(struct rchan_buf *buf,
return -EINVAL;

desc->vm_ops = &relay_file_mmap_ops;
- desc->vm_flags |= VM_DONTEXPAND;
+ vma_desc_set_flags(desc, VMA_DONTEXPAND_BIT);
desc->private_data = buf;

return 0;
diff --git a/mm/memory.c b/mm/memory.c
index 3852075ea62d..ad78cb7e64ec 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2955,7 +2955,7 @@ static inline int remap_p4d_range(struct mm_struct *mm, pgd_t *pgd,
return 0;
}

-static int get_remap_pgoff(vm_flags_t vm_flags, unsigned long addr,
+static int get_remap_pgoff(bool is_cow, unsigned long addr,
unsigned long end, unsigned long vm_start, unsigned long vm_end,
unsigned long pfn, pgoff_t *vm_pgoff_p)
{
@@ -2965,7 +2965,7 @@ static int get_remap_pgoff(vm_flags_t vm_flags, unsigned long addr,
* un-COW'ed pages by matching them up with "vma->vm_pgoff".
* See vm_normal_page() for details.
*/
- if (is_cow_mapping(vm_flags)) {
+ if (is_cow) {
if (addr != vm_start || end != vm_end)
return -EINVAL;
*vm_pgoff_p = pfn;
@@ -2986,7 +2986,7 @@ static int remap_pfn_range_internal(struct vm_area_struct *vma, unsigned long ad
if (WARN_ON_ONCE(!PAGE_ALIGNED(addr)))
return -EINVAL;

- VM_WARN_ON_ONCE((vma->vm_flags & VM_REMAP_FLAGS) != VM_REMAP_FLAGS);
+ VM_WARN_ON_ONCE(!vma_test_all_flags_mask(vma, VMA_REMAP_FLAGS));

BUG_ON(addr >= end);
pfn -= addr >> PAGE_SHIFT;
@@ -3110,9 +3110,9 @@ void remap_pfn_range_prepare(struct vm_area_desc *desc, unsigned long pfn)
* check it again on complete and will fail there if specified addr is
* invalid.
*/
- get_remap_pgoff(desc->vm_flags, desc->start, desc->end,
+ get_remap_pgoff(vma_desc_is_cow_mapping(desc), desc->start, desc->end,
desc->start, desc->end, pfn, &desc->pgoff);
- desc->vm_flags |= VM_REMAP_FLAGS;
+ vma_desc_set_flags_mask(desc, VMA_REMAP_FLAGS);
}

static int remap_pfn_range_prepare_vma(struct vm_area_struct *vma, unsigned long addr,
@@ -3121,13 +3121,12 @@ static int remap_pfn_range_prepare_vma(struct vm_area_struct *vma, unsigned long
unsigned long end = addr + PAGE_ALIGN(size);
int err;

- err = get_remap_pgoff(vma->vm_flags, addr, end,
- vma->vm_start, vma->vm_end,
- pfn, &vma->vm_pgoff);
+ err = get_remap_pgoff(is_cow_mapping(vma->vm_flags), addr, end,
+ vma->vm_start, vma->vm_end, pfn, &vma->vm_pgoff);
if (err)
return err;

- vm_flags_set(vma, VM_REMAP_FLAGS);
+ vma_set_flags_mask(vma, VMA_REMAP_FLAGS);
return 0;
}

--
2.52.0