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

[Lorenzo Stoakes (Oracle)]

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@xxxxxxxxxx>
---
 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