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

["Marc-André Lureau" <marcandre.lureau@redhat.com>]

Hi

----- Original Message -----
> On 11/03/2017 09:02 AM, Marc-André Lureau wrote:
> > Hi
> > 
> > ----- Original Message -----
> >> On 10/31/2017 11:40 AM, Marc-André Lureau wrote:
> >>> Those functions are called for memfd files, backed by shmem or
> >>> hugetlb (the next patches will handle hugetlb).
> >>>
> >>> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> >>> ---
> >>>  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.
> 
> Ah yes.  I should have addressed this when adding hugetlbfs memfd_create
> support.
> 
> Of course, one 'simple' way to address this would be to make CONFIG_HUGETLBFS
> depend on CONFIG_TMPFS.  Not sure what people think about this?
> 

I can't say much about that. But compiling the hugetlb seal support while TPMFS/memfd is disabled should not break anything. You won't be able to add seals, that's it.

I suppose memfd could be splitted off TPMFS, and depend on either HUGETLBFS || TPMFS?

> > Ack the function renaming part?
> 
> Yes, the remaining code looks fine to me.

Should I add your Review-by: for this patch then?

> 
> --
> Mike Kravetz
> 
> > 
> >> --
> >> 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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> >>
> 
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