Re: [PATCH 2/3] proc : no need to initialize proc_inode->fd inproc_get_inode

From: Andrew Morton
Date: Tue Sep 04 2012 - 18:49:30 EST


On Mon, 3 Sep 2012 22:14:06 +0800
yan <clouds.yan@xxxxxxxxx> wrote:

> It has been initialized in proc_alloc_inode.
>
> ...

I think what you mean here is that the preceding call to iget_locked()
will call alloc_inode() which will call proc_alloc_inode() which clears
pro_inode.fd.

And if iget_locked() instead found the inode via find_inode_fast(),
that inode will not have I_NEW set so this change has no effect.

Yes? Please do spell things out in this level of detail so that others
can check your logic.

> --- a/fs/proc/inode.c
> +++ b/fs/proc/inode.c
> @@ -450,7 +450,6 @@ struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
> return NULL;
> if (inode->i_state & I_NEW) {
> inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
> - PROC_I(inode)->fd = 0;
> PROC_I(inode)->pde = de;
>
> if (de->mode) {

I provided this changelog:

: proc_get_inode() obtains the inode via a call to iget_locked().
: iget_locked() calls alloc_inode() which will call proc_alloc_inode() which
: clears proc_inode.fd, so there is no need to clear this field in
: proc_get_inode().
:
: If iget_locked() instead found the inode via find_inode_fast(), that inode
: will not have I_NEW set so this change has no effect.

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