Re: [PATCH 2/6] shmem: rename functions that are memfd-related

From: Marc-Andrà Lureau
Date: Fri Nov 03 2017 - 12:02:32 EST


Hi

----- Original Message -----
> On 10/31/2017 11:40 AM, Marc-Andrà Lureau wrote:
> > Those functions are called for memfd files, backed by shmem or
> > hugetlb (the next patches will handle hugetlb).
> >
> > Signed-off-by: Marc-Andrà Lureau <marcandre.lureau@xxxxxxxxxx>
> > ---
> > fs/fcntl.c | 2 +-
> > include/linux/shmem_fs.h | 4 ++--
> > mm/shmem.c | 10 +++++-----
> > 3 files changed, 8 insertions(+), 8 deletions(-)
> >
> > diff --git a/fs/fcntl.c b/fs/fcntl.c
> > index 448a1119f0be..752c23743616 100644
> > --- a/fs/fcntl.c
> > +++ b/fs/fcntl.c
> > @@ -417,7 +417,7 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned
> > long arg,
> > break;
> > case F_ADD_SEALS:
> > case F_GET_SEALS:
> > - err = shmem_fcntl(filp, cmd, arg);
> > + err = memfd_fcntl(filp, cmd, arg);
> > break;
> > case F_GET_RW_HINT:
> > case F_SET_RW_HINT:
> > diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
> > index 557d0c3b6eca..0dac8c0f4aa4 100644
> > --- a/include/linux/shmem_fs.h
> > +++ b/include/linux/shmem_fs.h
> > @@ -109,11 +109,11 @@ extern void shmem_uncharge(struct inode *inode, long
> > pages);
> >
> > #ifdef CONFIG_TMPFS
> >
> > -extern long shmem_fcntl(struct file *file, unsigned int cmd, unsigned long
> > arg);
> > +extern long memfd_fcntl(struct file *file, unsigned int cmd, unsigned long
> > arg);
> >
> > #else
> >
> > -static inline long shmem_fcntl(struct file *f, unsigned int c, unsigned
> > long a)
> > +static inline long memfd_fcntl(struct file *f, unsigned int c, unsigned
> > long a)
> > {
> > return -EINVAL;
> > }
>
> Do we want memfd_fcntl() to work for hugetlbfs if CONFIG_TMPFS is not
> defined? I admit that having CONFIG_HUGETLBFS defined without CONFIG_TMPFS
> is unlikely, but I think possible. Based on the above #ifdef/#else, I
> think hugetlbfs seals will not work if CONFIG_TMPFS is not defined.

Good point, memfd_create() will not exists either.

I think this is a separate concern, and preexisting from this patch series though.

Ack the function renaming part?

> --
> Mike Kravetz
>
> > diff --git a/mm/shmem.c b/mm/shmem.c
> > index 37260c5e12fa..b7811979611f 100644
> > --- a/mm/shmem.c
> > +++ b/mm/shmem.c
> > @@ -2722,7 +2722,7 @@ static int shmem_wait_for_pins(struct address_space
> > *mapping)
> > F_SEAL_GROW | \
> > F_SEAL_WRITE)
> >
> > -static int shmem_add_seals(struct file *file, unsigned int seals)
> > +static int memfd_add_seals(struct file *file, unsigned int seals)
> > {
> > struct inode *inode = file_inode(file);
> > struct shmem_inode_info *info = SHMEM_I(inode);
> > @@ -2792,7 +2792,7 @@ static int shmem_add_seals(struct file *file,
> > unsigned int seals)
> > return error;
> > }
> >
> > -static int shmem_get_seals(struct file *file)
> > +static int memfd_get_seals(struct file *file)
> > {
> > if (file->f_op != &shmem_file_operations)
> > return -EINVAL;
> > @@ -2800,7 +2800,7 @@ static int shmem_get_seals(struct file *file)
> > return SHMEM_I(file_inode(file))->seals;
> > }
> >
> > -long shmem_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
> > +long memfd_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
> > {
> > long error;
> >
> > @@ -2810,10 +2810,10 @@ long shmem_fcntl(struct file *file, unsigned int
> > cmd, unsigned long arg)
> > if (arg > UINT_MAX)
> > return -EINVAL;
> >
> > - error = shmem_add_seals(file, arg);
> > + error = memfd_add_seals(file, arg);
> > break;
> > case F_GET_SEALS:
> > - error = shmem_get_seals(file);
> > + error = memfd_get_seals(file);
> > break;
> > default:
> > error = -EINVAL;
> >
>
> --
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