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Date: Wed, 30 Aug 2017 16:39:00 +0100
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Christoph Hellwig <hch@lst.de>
Cc: arve@android.com, riandrews@android.com, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 06/16] fs: fix kernel_write prototype
Message-ID: <20170830153859.GO5426@ZenIV.linux.org.uk>
References: <20170830150007.3953-1-hch@lst.de>
 <20170830150007.3953-7-hch@lst.de>
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On Wed, Aug 30, 2017 at 04:59:57PM +0200, Christoph Hellwig wrote:

>  	for (prot = 0; prot < prot_length;) {
>  		sector_t len = min_t(sector_t, bufsize, prot_length - prot);
> -		ssize_t ret = kernel_write(prot_fd, buf, len, pos + prot);
> +		ssize_t ret = kernel_write(prot_fd, buf, len, &pos);
>  
>  		if (ret != len) {
>  			pr_err("vfs_write to prot file failed: %zd\n", ret);
>  			return ret < 0 ? ret : -ENODEV;
>  		}
> -		prot += ret;
>  	}

And that loop will terminate because of...?  IOW, the same bug class as in
the kernel_read() patch.