[PATCH 5/6] mm: reintroduce vma_desc_test() as a singular flag test

Lorenzo Stoakes (Oracle)
2026-03-05T10:50:49Z

Similar to vma_flags_test(), we have previously renamed vma_desc_test() to
vma_desc_test_any(). Now that is in place, we can reintroduce
vma_desc_test() to explicitly check for a single VMA flag.

As with vma_flags_test(), this is useful as often flag tests are against a
single flag, and vma_desc_test_any(flags, VMA_READ_BIT) reads oddly and
potentially causes confusion.

As with vma_flags_test() a combination of sparse and vma_flags_t being a
struct means that users cannot misuse this function without it getting
flagged.

Also update the VMA tests to reflect this change.

Signed-off-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
---
drivers/char/mem.c | 2 +-
fs/hugetlbfs/inode.c | 2 +-
fs/ntfs3/file.c | 2 +-
fs/resctrl/pseudo_lock.c | 2 +-
include/linux/dax.h | 4 ++--
include/linux/mm.h | 11 +++++++++++
mm/hugetlb.c | 12 ++++++------
tools/testing/vma/include/dup.h | 6 ++++++
8 files changed, 29 insertions(+), 12 deletions(-)

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 5118787d0954..5fd421e48c04 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -520,7 +520,7 @@ static int mmap_zero_prepare(struct vm_area_desc *desc)
#ifndef CONFIG_MMU
return -ENOSYS;
#endif
- if (vma_desc_test_any(desc, VMA_SHARED_BIT))
+ if (vma_desc_test(desc, VMA_SHARED_BIT))
return shmem_zero_setup_desc(desc);

desc->action.success_hook = mmap_zero_private_success;
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 079ffaaf1f6c..cd6b22f6e2b1 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -164,7 +164,7 @@ static int hugetlbfs_file_mmap_prepare(struct vm_area_desc *desc)
goto out;

ret = 0;
- if (vma_desc_test_any(desc, VMA_WRITE_BIT) && inode->i_size < len)
+ if (vma_desc_test(desc, VMA_WRITE_BIT) && inode->i_size < len)
i_size_write(inode, len);
out:
inode_unlock(inode);
diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
index c5e2181f9f02..fbdfaf989a31 100644
--- a/fs/ntfs3/file.c
+++ b/fs/ntfs3/file.c
@@ -276,7 +276,7 @@ static int ntfs_file_mmap_prepare(struct vm_area_desc *desc)
struct file *file = desc->file;
struct inode *inode = file_inode(file);
struct ntfs_inode *ni = ntfs_i(inode);
- const bool rw = vma_desc_test_any(desc, VMA_WRITE_BIT);
+ const bool rw = vma_desc_test(desc, VMA_WRITE_BIT);
int err;

/* Avoid any operation if inode is bad. */
diff --git a/fs/resctrl/pseudo_lock.c b/fs/resctrl/pseudo_lock.c
index 79a006c6f26c..d1cb0986006e 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 (!vma_desc_test_any(desc, VMA_SHARED_BIT)) {
+ if (!vma_desc_test(desc, VMA_SHARED_BIT)) {
mutex_unlock(&rdtgroup_mutex);
return -EINVAL;
}
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 535019001577..10a7cc79aea5 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -69,7 +69,7 @@ static inline bool daxdev_mapping_supported(const struct vm_area_desc *desc,
const struct inode *inode,
struct dax_device *dax_dev)
{
- if (!vma_desc_test_any(desc, VMA_SYNC_BIT))
+ if (!vma_desc_test(desc, VMA_SYNC_BIT))
return true;
if (!IS_DAX(inode))
return false;
@@ -115,7 +115,7 @@ static inline bool daxdev_mapping_supported(const struct vm_area_desc *desc,
const struct inode *inode,
struct dax_device *dax_dev)
{
- return !vma_desc_test_any(desc, VMA_SYNC_BIT);
+ return !vma_desc_test(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 5622d04c9ba9..9bdfa1a91552 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1193,6 +1193,17 @@ static inline void vma_set_flags_mask(struct vm_area_struct *vma,
#define vma_set_flags(vma, ...) \
vma_set_flags_mask(vma, mk_vma_flags(__VA_ARGS__))

+/*
+ * Test whether a specific VMA flag is set in a VMA descriptor, e.g.:
+ *
+ * if (vma_desc_test(desc, VMA_READ_BIT)) { ... }
+ */
+static __always_inline bool vma_desc_test(const struct vm_area_desc *desc,
+ vma_flag_t bit)
+{
+ return vma_flags_test(&desc->vma_flags, bit);
+}
+
/* Helper to test any VMA flags in a VMA descriptor. */
static inline bool vma_desc_test_any_mask(const struct vm_area_desc *desc,
vma_flags_t flags)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index bd9f3b2d2cb0..8cde83fb8a5a 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1194,7 +1194,7 @@ static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
static void set_vma_desc_resv_map(struct vm_area_desc *desc, struct resv_map *map)
{
VM_WARN_ON_ONCE(!is_vma_hugetlb_flags(&desc->vma_flags));
- VM_WARN_ON_ONCE(vma_desc_test_any(desc, VMA_MAYSHARE_BIT));
+ VM_WARN_ON_ONCE(vma_desc_test(desc, VMA_MAYSHARE_BIT));

desc->private_data = map;
}
@@ -1202,7 +1202,7 @@ static void set_vma_desc_resv_map(struct vm_area_desc *desc, struct resv_map *ma
static void set_vma_desc_resv_flags(struct vm_area_desc *desc, unsigned long flags)
{
VM_WARN_ON_ONCE(!is_vma_hugetlb_flags(&desc->vma_flags));
- VM_WARN_ON_ONCE(vma_desc_test_any(desc, VMA_MAYSHARE_BIT));
+ VM_WARN_ON_ONCE(vma_desc_test(desc, VMA_MAYSHARE_BIT));

desc->private_data = (void *)((unsigned long)desc->private_data | flags);
}
@@ -6600,7 +6600,7 @@ long hugetlb_reserve_pages(struct inode *inode,
* to reserve the full area even if read-only as mprotect() may be
* called to make the mapping read-write. Assume !desc is a shm mapping
*/
- if (!desc || vma_desc_test_any(desc, VMA_MAYSHARE_BIT)) {
+ if (!desc || vma_desc_test(desc, VMA_MAYSHARE_BIT)) {
/*
* resv_map can not be NULL as hugetlb_reserve_pages is only
* called for inodes for which resv_maps were created (see
@@ -6634,7 +6634,7 @@ long hugetlb_reserve_pages(struct inode *inode,
if (err < 0)
goto out_err;

- if (desc && !vma_desc_test_any(desc, VMA_MAYSHARE_BIT) && h_cg) {
+ if (desc && !vma_desc_test(desc, VMA_MAYSHARE_BIT) && h_cg) {
/* For private mappings, the hugetlb_cgroup uncharge info hangs
* of the resv_map.
*/
@@ -6671,7 +6671,7 @@ long hugetlb_reserve_pages(struct inode *inode,
* consumed reservations are stored in the map. Hence, nothing
* else has to be done for private mappings here
*/
- if (!desc || vma_desc_test_any(desc, VMA_MAYSHARE_BIT)) {
+ if (!desc || vma_desc_test(desc, VMA_MAYSHARE_BIT)) {
add = region_add(resv_map, from, to, regions_needed, h, h_cg);

if (unlikely(add < 0)) {
@@ -6735,7 +6735,7 @@ long hugetlb_reserve_pages(struct inode *inode,
hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h),
chg * pages_per_huge_page(h), h_cg);
out_err:
- if (!desc || vma_desc_test_any(desc, VMA_MAYSHARE_BIT))
+ if (!desc || vma_desc_test(desc, VMA_MAYSHARE_BIT))
/* Only call region_abort if the region_chg succeeded but the
* region_add failed or didn't run.
*/
diff --git a/tools/testing/vma/include/dup.h b/tools/testing/vma/include/dup.h
index 630478f0d583..5eb313beb43d 100644
--- a/tools/testing/vma/include/dup.h
+++ b/tools/testing/vma/include/dup.h
@@ -922,6 +922,12 @@ static inline void vma_set_flags_mask(struct vm_area_struct *vma,
#define vma_set_flags(vma, ...) \
vma_set_flags_mask(vma, mk_vma_flags(__VA_ARGS__))

+static __always_inline bool vma_desc_test(const struct vm_area_desc *desc,
+ vma_flag_t bit)
+{
+ return vma_flags_test(&desc->vma_flags, bit);
+}
+
static inline bool vma_desc_test_any_mask(const struct vm_area_desc *desc,
vma_flags_t flags)
{
--
2.53.0