Date: Fri, 21 Oct 2016 06:24:00 -0700
From: Christoph Hellwig <hch@infradead.org>
To: Richard Weinberger <richard@nod.at>
Cc: Christoph Hellwig <hch@infradead.org>, 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
Subject: Re: [PATCH 01/26] fscrypto: Add buffer operations
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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.