Re: [PATCH 09/10] fs: convert most other generic_file_*mmap() users to .mmap_prepare()

Christian Brauner
2025-06-17T11:54:54Z

On Tue, Jun 17, 2025 at 12:23:41PM +0200, Jan Kara wrote:
> On Mon 16-06-25 20:33:28, Lorenzo Stoakes wrote:
> > Update nearly all generic_file_mmap() and generic_file_readonly_mmap()
> > callers to use generic_file_mmap_prepare() and
> > generic_file_readonly_mmap_prepare() respectively.
> >
> > We update blkdev, 9p, afs, erofs, ext2, nfs, ntfs3, smb, ubifs and vboxsf
> > file systems this way.
> >
> > Remaining users we cannot yet update are ecryptfs, fuse and cramfs. The
> > former two are nested file systems that must support any underlying file
> > ssytem, and cramfs inserts a mixed mapping which currently requires a VMA.
> >
> > Once all file systems have been converted to mmap_prepare(), we can then
> > update nested file systems.
> >
> > Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
>
> Overall the patch looks good. Just a couple of notes regarding pointless
> local variable being created...
>
> > ---
> > block/fops.c | 9 +++++----
> > fs/9p/vfs_file.c | 11 ++++++-----
> > fs/afs/file.c | 11 ++++++-----
> > fs/erofs/data.c | 16 +++++++++-------
> > fs/ext2/file.c | 12 +++++++-----
> > fs/nfs/file.c | 13 +++++++------
> > fs/nfs/internal.h | 2 +-
> > fs/nfs/nfs4file.c | 2 +-
> > fs/ntfs3/file.c | 15 ++++++++-------
> > fs/smb/client/cifsfs.c | 12 ++++++------
> > fs/smb/client/cifsfs.h | 4 ++--
> > fs/smb/client/file.c | 14 ++++++++------
> > fs/ubifs/file.c | 8 ++++----
> > fs/vboxsf/file.c | 8 ++++----
> > 14 files changed, 74 insertions(+), 63 deletions(-)
> >
> > diff --git a/block/fops.c b/block/fops.c
> > index 1309861d4c2c..5a0ebc81e489 100644
> > --- a/block/fops.c
> > +++ b/block/fops.c
> > @@ -911,14 +911,15 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start,
> > return error;
> > }
> >
> > -static int blkdev_mmap(struct file *file, struct vm_area_struct *vma)
> > +static int blkdev_mmap_prepare(struct vm_area_desc *desc)
> > {
> > + struct file *file = desc->file;
> > struct inode *bd_inode = bdev_file_inode(file);
>
> I guess no need to create 'file' variable here since it has only one use in
> the line above...

Agreed, fixed in-tree.

> > -static int afs_file_mmap(struct file *file, struct vm_area_struct *vma)
> > +static int afs_file_mmap_prepare(struct vm_area_desc *desc)
> > {
> > + struct file *file = desc->file;
> > struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
>
> Same comment about pointless local variable here as well.

Same.

> > -static int erofs_file_mmap(struct file *file, struct vm_area_struct *vma)
> > +static int erofs_file_mmap_prepare(struct vm_area_desc *desc)
> > {
> > + struct file *file = desc->file;
> > +
> > if (!IS_DAX(file_inode(file)))
>
> And here...

Same.

> > -int cifs_file_strict_mmap(struct file *file, struct vm_area_struct *vma)
> > +int cifs_file_strict_mmap_prepare(struct vm_area_desc *desc)
> > {
> > + struct file *file = desc->file;
> > int xid, rc = 0;
> > struct inode *inode = file_inode(file);
>
> Again pointless local variable 'file' here.

Same.

> > -int cifs_file_mmap(struct file *file, struct vm_area_struct *vma)
> > +int cifs_file_mmap_prepare(struct vm_area_desc *desc)
> > {
> > + struct file *file = desc->file;
> > int rc, xid;
>
> And here (the only use is in cifs_revalidate_file(file)).

Same.