Re: [PATCH] Allow to disable shmem.o

[Hugh Dickins]

On 8 Aug 2004, Andi Kleen wrote:
> On Sun, Aug 08, 2004 at 09:07:05AM -0500, Matt Mackall wrote:
> > +extern struct inode *ramfs_get_inode(struct super_block *sb, int mode, dev_t dev);
> > +extern struct super_block *ramfs_get_sb(struct file_system_type *fs_type,
> > +	 int flags, const char *dev_name, void *data);
> > +extern struct file_operations ramfs_file_operations;
> > +extern struct vm_operations_struct generic_file_vm_ops;
> 
> This should be all in header files.

Yes.

> > +	if (IS_ERR(shm_mnt))
> > +		return (void *)shm_mnt;
> 
> Why this strange cast? 

Matt copied from shmem.c, so blame me.  Strange cast because it's one
of those IS_ERR things, an -errno hiding inside a pointer, and it's
being propagated from an initialization error on shm_mnt to a runtime
error on any struct file for that mount.  I wrote (void *) because it
seemed to express the ambiguity better than pretending struct file *.

> > +	inode = ramfs_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0);
> 
> Hmm, won't this allow everybody else to open it in /proc/pid/fd/ ? 
> (existing shmem.c seems to use it too, but it looks a bit bogus) 

But there's no fd associated with it?

Hugh

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