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

Vlastimil Babka
2025-06-17T18:58:12Z

On 6/16/25 21:33, Lorenzo Stoakes wrote:
> 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>

Acked-by: Vlastimil Babka <vbabka@suse.cz>

> ---
> 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);
> }