Re: [PATCH] crypto: allow to assign gfp_t for __crypto_alloc_tfm

From: Jaegeuk Kim <jaegeuk@kernel.org>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: davem@davemloft.net, linux-crypto@vger.kernel.org,
	linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-f2fs-devel@lists.sourceforge.net, ecryptfs@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] crypto: allow to assign gfp_t for __crypto_alloc_tfm
Date: Tue, 19 May 2015 00:13:17 -0700	[thread overview]
Message-ID: <20150519071317.GB40012@jaegeuk-mac02.hsd1.ca.comcast.net> (raw)
In-Reply-To: <20150519065929.GA28610@gondor.apana.org.au>

On Tue, May 19, 2015 at 02:59:29PM +0800, Herbert Xu wrote:
> On Mon, May 18, 2015 at 11:58:12PM -0700, Jaegeuk Kim wrote:
> >
> > > So where does the key get generated? The crypto tfm should be
> > > allocated when you generate the key.
> > 
> > In fs/ext4/crypto.c,
> > 
> >  - writepage
> >    - ext4_encrypt
> >      - ext4_get_crypto_ctx
> >        - crypto_alloc_ablkcipher
> >      - ext4_page_crypto
> >        - crypto_ablkcipher_setkey
> >        - ablkcipher_request_alloc(GFP_NOFS)
> >        - ablkcipher_request_set_crypt(PAGE_CACHE_SIZE)
> >        - crypto_ablkcipher_encrypt
> > 
> >  - end_io
> >    - crypto_free_tfm
> 
> No that's where you set the key, not where you generate the key.

The key generation is done by ext4_generate_encryption_key in
fs/ext4/crypto_key.c.
And, ext4_file_mmap and ext4_file_open trigger it.

> -- 
> Email: Herbert Xu <herbert@gondor.apana.org.au>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt