Re: [RFC PATCH 1/6] shmem: use alloc_file instead of init_file

From: Eric Paris
Date: Fri Dec 04 2009 - 09:20:32 EST


On Fri, 2009-12-04 at 06:58 +0100, Miklos Szeredi wrote:
> On Thu, 03 Dec 2009, Eric Paris wrote:
> > shmem uses get_empty_filp() and then init_file(). Their is no good reason
> > not to just use alloc_file() like everything else.
>
> There's a more in this patch, though, and none of that is explained...
>
> >
> > Signed-off-by: Eric Paris <eparis@xxxxxxxxxx>
> > ---
> >
> > mm/shmem.c | 20 ++++++++++----------
> > 1 files changed, 10 insertions(+), 10 deletions(-)
> >
> > diff --git a/mm/shmem.c b/mm/shmem.c
> > index 356dd99..831f8bb 100644
> > --- a/mm/shmem.c
> > +++ b/mm/shmem.c
> > @@ -2640,32 +2640,32 @@ struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags
> > if (!dentry)
> > goto put_memory;
> >
> > - error = -ENFILE;
> > - file = get_empty_filp();
> > - if (!file)
> > - goto put_dentry;
> > -
> > error = -ENOSPC;
> > inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0, flags);
> > if (!inode)
> > - goto close_file;
> > + goto put_dentry;
> >
> > d_instantiate(dentry, inode);
> > inode->i_size = size;
> > inode->i_nlink = 0; /* It is unlinked */
> > - init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ,
> > - &shmem_file_operations);
> > +
> > + error = -ENFILE;
> > + file = alloc_file(shm_mnt, dentry, FMODE_WRITE | FMODE_READ,
> > + &shmem_file_operations);
> > + if (!file)
> > + goto put_dentry;
> >
> > #ifndef CONFIG_MMU
> > error = ramfs_nommu_expand_for_mapping(inode, size);
> > if (error)
> > goto close_file;
> > #endif
> > - ima_counts_get(file);
>
> Where's this gone?

That's the impetuous for the whole patch series. I originally did the
ima rework first an the vfs changes second, but decided to push the vfs
stuff first and I guess I forgot to back out this bit of ima change I
had done. This will be dropped for actual submission.

> > return file;
> >
> > +#ifndef CONFIG_MMU
> > close_file:
>
> I suggest moving this piece of cleanup into the ifdef above, instead
> of adding more ifdefs.

Ok.

> > - put_filp(file);
> > + fput(file);
>
> OK, put_filp() seems to have been wrong here, but please document it
> in the changelog.

It was only wrong in the ifndef !CONFIG_MMU case. The other error path
which ended up here used it correctly. In any case, I'll mention it in
the changelog.

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