Subject: Re: [PATCH 01/26] fscrypto: Add buffer operations
To: Christoph Hellwig <hch@infradead.org>
References: <1477054121-10198-1-git-send-email-richard@nod.at>
 <1477054121-10198-2-git-send-email-richard@nod.at>
 <20161021130558.GA2411@infradead.org>
 <9c80d1d0-0237-606f-91ce-a004c3694aa5@nod.at>
 <20161021132400.GA28880@infradead.org>
Cc: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, dedekind1@gmail.com,
        adrian.hunter@intel.com, tytso@mit.edu, jaegeuk@kernel.org,
        david@sigma-star.at, wd@denx.de, sbabic@denx.de, dengler@linutronix.de
From: Richard Weinberger <richard@nod.at>
Message-ID: <b7f1f92e-3e0f-ba91-fc36-dcf45c6d461d@nod.at>
Date: Mon, 24 Oct 2016 09:05:42 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101
 Thunderbird/45.2
MIME-Version: 1.0
In-Reply-To: <20161021132400.GA28880@infradead.org>
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 793
Lines: 21

Christoph,

On 21.10.2016 15:24, Christoph Hellwig wrote:
> On Fri, Oct 21, 2016 at 03:17:03PM +0200, Richard Weinberger wrote:
>> UBIFS works on kmalloc()'ed buffers where it constructs the NAND/NOR pages
>> which will be written to the MTD. JFFS2 does the same.
> 
> Yes, you can trivially do a virt_to_page on a kmalloc buffer.
> 
>> Another reason why I did the buffer functions is because fscrypt_encrypt_page()
>> always allocates a bounce page as temporary memory. For ext4 this is needed,
>> for UBIFS not.
>> UBIFS has already a construction buffer, especially since it also does compression.
> 
> We should defintively find a way to avoid that, but it's a separate
> issue from adding another API just to pass buffers.

Okay, I'll address this in v2 of my series.

Thanks,
//richard