Re: [PATCH 3/6] block: open code __generic_file_write_iter for blkdev writes

[Christoph Hellwig <hch@lst.de>]

On Tue, Aug 29, 2023 at 03:06:14AM +0100, Al Viro wrote:
> On Tue, Aug 01, 2023 at 07:21:58PM +0200, Christoph Hellwig wrote:
> > @@ -569,7 +594,23 @@ static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
> >  		iov_iter_truncate(from, size);
> >  	}
> >  
> > -	ret = __generic_file_write_iter(iocb, from);
> > +	ret = file_remove_privs(file);
> > +	if (ret)
> > +		return ret;
> 
> That chunk is a bit of a WTF generator...  Thankfully,
> 
> static int __file_remove_privs(struct file *file, unsigned int flags)
> {
>         struct dentry *dentry = file_dentry(file);
> 	struct inode *inode = file_inode(file);
> 	int error = 0;
> 	int kill;
> 
> 	if (IS_NOSEC(inode) || !S_ISREG(inode->i_mode))
> 		return 0;
> 
> means that it's really a no-op.  But I'd still suggest
> removing it, just to reduce the amount of head-scratching
> for people who'll be reading that code later...

I'll send an incremental patch to remove it once the changes hit
Linus' tree.