[PATCH 01/10] mm: rename call_mmap/mmap_prepare to vfs_mmap/mmap_prepare

[Lorenzo Stoakes <lorenzo.stoakes@oracle.com>]

The call_mmap() function violates the existing convention in
include/linux/fs.h whereby invocations of virtual file system hooks is
performed by functions prefixed with vfs_xxx().

Correct this by renaming call_mmap() to vfs_mmap(). This also avoids
confusion as to the fact that f_op->mmap_prepare may be invoked here.

Also rename __call_mmap_prepare() function to vfs_mmap_prepare() and adjust
to accept a file parameter, this is useful later for nested file systems.

Finally, fix up the VMA userland tests and ensure the mmap_prepare -> mmap
shim is implemented there.

Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c |  2 +-
 fs/backing-file.c                          |  2 +-
 fs/coda/file.c                             |  4 +--
 include/linux/fs.h                         |  5 ++--
 ipc/shm.c                                  |  2 +-
 mm/internal.h                              |  2 +-
 mm/vma.c                                   |  2 +-
 tools/testing/vma/vma_internal.h           | 32 ++++++++++++++++++----
 8 files changed, 35 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
index 05e440643aa2..f4f1c979d1b9 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
@@ -105,7 +105,7 @@ static int i915_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *
 	if (!obj->base.filp)
 		return -ENODEV;
 
-	ret = call_mmap(obj->base.filp, vma);
+	ret = vfs_mmap(obj->base.filp, vma);
 	if (ret)
 		return ret;
 
diff --git a/fs/backing-file.c b/fs/backing-file.c
index 763fbe9b72b2..04018679bf69 100644
--- a/fs/backing-file.c
+++ b/fs/backing-file.c
@@ -339,7 +339,7 @@ int backing_file_mmap(struct file *file, struct vm_area_struct *vma,
 	vma_set_file(vma, file);
 
 	old_cred = override_creds(ctx->cred);
-	ret = call_mmap(vma->vm_file, vma);
+	ret = vfs_mmap(vma->vm_file, vma);
 	revert_creds(old_cred);
 
 	if (ctx->accessed)
diff --git a/fs/coda/file.c b/fs/coda/file.c
index 148856a582a9..2e6ea9319b35 100644
--- a/fs/coda/file.c
+++ b/fs/coda/file.c
@@ -199,10 +199,10 @@ coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
 	spin_unlock(&cii->c_lock);
 
 	vma->vm_file = get_file(host_file);
-	ret = call_mmap(vma->vm_file, vma);
+	ret = vfs_mmap(vma->vm_file, vma);
 
 	if (ret) {
-		/* if call_mmap fails, our caller will put host_file so we
+		/* if vfs_mmap fails, our caller will put host_file so we
 		 * should drop the reference to the coda_file that we got.
 		 */
 		fput(coda_file);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 93ee0d2d6f1a..7120f80255b3 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2278,7 +2278,7 @@ static inline bool file_has_valid_mmap_hooks(struct file *file)
 
 int compat_vma_mmap_prepare(struct file *file, struct vm_area_struct *vma);
 
-static inline int call_mmap(struct file *file, struct vm_area_struct *vma)
+static inline int vfs_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	if (file->f_op->mmap_prepare)
 		return compat_vma_mmap_prepare(file, vma);
@@ -2286,8 +2286,7 @@ static inline int call_mmap(struct file *file, struct vm_area_struct *vma)
 	return file->f_op->mmap(file, vma);
 }
 
-static inline int __call_mmap_prepare(struct file *file,
-		struct vm_area_desc *desc)
+static inline int vfs_mmap_prepare(struct file *file, struct vm_area_desc *desc)
 {
 	return file->f_op->mmap_prepare(desc);
 }
diff --git a/ipc/shm.c b/ipc/shm.c
index 492fcc699985..a9310b6dbbc3 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -602,7 +602,7 @@ static int shm_mmap(struct file *file, struct vm_area_struct *vma)
 	if (ret)
 		return ret;
 
-	ret = call_mmap(sfd->file, vma);
+	ret = vfs_mmap(sfd->file, vma);
 	if (ret) {
 		__shm_close(sfd);
 		return ret;
diff --git a/mm/internal.h b/mm/internal.h
index 3823fb356d3b..a55c88afff6d 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -165,7 +165,7 @@ static inline void *folio_raw_mapping(const struct folio *folio)
  */
 static inline int mmap_file(struct file *file, struct vm_area_struct *vma)
 {
-	int err = call_mmap(file, vma);
+	int err = vfs_mmap(file, vma);
 
 	if (likely(!err))
 		return 0;
diff --git a/mm/vma.c b/mm/vma.c
index 5d35adadf2b5..f548bede3bbe 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -2582,7 +2582,7 @@ static int call_mmap_prepare(struct mmap_state *map)
 	};
 
 	/* Invoke the hook. */
-	err = __call_mmap_prepare(map->file, &desc);
+	err = vfs_mmap_prepare(map->file, &desc);
 	if (err)
 		return err;
 
diff --git a/tools/testing/vma/vma_internal.h b/tools/testing/vma/vma_internal.h
index d7fea56e3bb3..51dd122b8d50 100644
--- a/tools/testing/vma/vma_internal.h
+++ b/tools/testing/vma/vma_internal.h
@@ -1458,6 +1458,27 @@ static inline void free_anon_vma_name(struct vm_area_struct *vma)
 	(void)vma;
 }
 
+/* Declared in vma.h. */
+static inline void set_vma_from_desc(struct vm_area_struct *vma,
+		struct vm_area_desc *desc);
+
+static inline struct vm_area_desc *vma_to_desc(struct vm_area_struct *vma,
+		struct vm_area_desc *desc);
+
+static int compat_vma_mmap_prepare(struct file *file,
+		struct vm_area_struct *vma)
+{
+	struct vm_area_desc desc;
+	int err;
+
+	err = file->f_op->mmap_prepare(vma_to_desc(vma, &desc));
+	if (err)
+		return err;
+	set_vma_from_desc(vma, &desc);
+
+	return 0;
+}
+
 /* Did the driver provide valid mmap hook configuration? */
 static inline bool file_has_valid_mmap_hooks(struct file *file)
 {
@@ -1467,22 +1488,21 @@ static inline bool file_has_valid_mmap_hooks(struct file *file)
 	/* Hooks are mutually exclusive. */
 	if (WARN_ON_ONCE(has_mmap && has_mmap_prepare))
 		return false;
-	if (WARN_ON_ONCE(!has_mmap && !has_mmap_prepare))
+	if (!has_mmap && !has_mmap_prepare)
 		return false;
 
 	return true;
 }
 
-static inline int call_mmap(struct file *file, struct vm_area_struct *vma)
+static inline int vfs_mmap(struct file *file, struct vm_area_struct *vma)
 {
-	if (WARN_ON_ONCE(file->f_op->mmap_prepare))
-		return -EINVAL;
+	if (file->f_op->mmap_prepare)
+		return compat_vma_mmap_prepare(file, vma);
 
 	return file->f_op->mmap(file, vma);
 }
 
-static inline int __call_mmap_prepare(struct file *file,
-		struct vm_area_desc *desc)
+static inline int vfs_mmap_prepare(struct file *file, struct vm_area_desc *desc)
 {
 	return file->f_op->mmap_prepare(desc);
 }
-- 
2.49.0