From: Jaegeuk Kim Subject: Re: [PATCH] crypto: allow to assign gfp_t for __crypto_alloc_tfm Date: Mon, 18 May 2015 23:58:12 -0700 Message-ID: <20150519065812.GA40012@jaegeuk-mac02.hsd1.ca.comcast.net> References: <1432014416-39326-1-git-send-email-jaegeuk@kernel.org> <20150519054945.GA28060@gondor.apana.org.au> <20150519062430.GA39588@jaegeuk-mac02.hsd1.ca.comcast.net> <20150519063211.GA28347@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii 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 To: Herbert Xu Return-path: Received: from mail.kernel.org ([198.145.29.136]:59645 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751070AbbESG6R (ORCPT ); Tue, 19 May 2015 02:58:17 -0400 Content-Disposition: inline In-Reply-To: <20150519063211.GA28347@gondor.apana.org.au> Sender: linux-crypto-owner@vger.kernel.org List-ID: On Tue, May 19, 2015 at 02:32:11PM +0800, Herbert Xu wrote: > On Mon, May 18, 2015 at 11:24:30PM -0700, Jaegeuk Kim wrote: > > > > The call path in fs/ext4/crypto.c is: > > - writepage > > - ext4_encrypt > > - ext4_get_crypto_ctx > > - crypto_alloc_ablkcipher > > > > AFAIK, this way can achieve to reduce memory footprint gracefully. > > Just before submitting bios, fs allocates the required memory, and then end_io > > will free them in pair. > > 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 Thanks, > > Cheers, > -- > Email: Herbert Xu > Home Page: http://gondor.apana.org.au/~herbert/ > PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt