From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 68F08C433DF for ; Mon, 17 Aug 2020 17:43:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5627E20716 for ; Mon, 17 Aug 2020 17:43:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388952AbgHQRni (ORCPT ); Mon, 17 Aug 2020 13:43:38 -0400 Received: from mga04.intel.com ([192.55.52.120]:15588 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389020AbgHQRng (ORCPT ); Mon, 17 Aug 2020 13:43:36 -0400 IronPort-SDR: 7qTGAf6WCxdsON/v/hgHw5/Ruc4bSQc7PZ9i29PEWvrfqNz+I8Kkgi/dNKxVCo72h9xmm4CruZ 6ckFsnnnbj4w== X-IronPort-AV: E=McAfee;i="6000,8403,9716"; a="152171570" X-IronPort-AV: E=Sophos;i="5.76,324,1592895600"; d="scan'208";a="152171570" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Aug 2020 10:43:35 -0700 IronPort-SDR: EsGJDlG2Elfx4PTVo5feMiTZDFCT7ABc4DH894/gUpMct7O9/tuNSP2eKBlobYUnIYJDzVDwcx ONdxB+GKxpZg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.76,324,1592895600"; d="scan'208";a="326478021" Received: from smile.fi.intel.com (HELO smile) ([10.237.68.40]) by orsmga008.jf.intel.com with ESMTP; 17 Aug 2020 10:43:32 -0700 Received: from andy by smile with local (Exim 4.94) (envelope-from ) id 1k7j6C-009TgH-Dv; Mon, 17 Aug 2020 20:39:08 +0300 Date: Mon, 17 Aug 2020 20:39:08 +0300 From: Andy Shevchenko To: Bartosz Golaszewski Cc: Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , Michal Simek , Greg Kroah-Hartman , Guenter Roeck , linux-iio@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Bartosz Golaszewski Subject: Re: [PATCH v7 1/3] devres: provide devm_krealloc() Message-ID: <20200817173908.GS1891694@smile.fi.intel.com> References: <20200817170535.17041-1-brgl@bgdev.pl> <20200817170535.17041-2-brgl@bgdev.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200817170535.17041-2-brgl@bgdev.pl> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org On Mon, Aug 17, 2020 at 07:05:33PM +0200, Bartosz Golaszewski wrote: > From: Bartosz Golaszewski > > Implement the managed variant of krealloc(). This function works with > all memory allocated by devm_kmalloc() (or devres functions using it > implicitly like devm_kmemdup(), devm_kstrdup() etc.). > > Managed realloc'ed chunks can be manually released with devm_kfree(). Thanks for an update! My comments / questions below. ... > +static struct devres *to_devres(void *data) > +{ > + return (struct devres *)((u8 *)data - ALIGN(sizeof(struct devres), > + ARCH_KMALLOC_MINALIGN)); Do you really need both explicit castings? > +} ... > + total_old_size = ksize(to_devres(ptr)); But how you can guarantee this pointer: - belongs to devres, - hasn't gone while you run a ksize()? ... > + new_dr = alloc_dr(devm_kmalloc_release, > + total_new_size, gfp, dev_to_node(dev)); Can you move some parameters to the previous line? > + if (!new_dr) > + return NULL; ... > + spin_lock_irqsave(&dev->devres_lock, flags); > + > + old_dr = find_dr(dev, devm_kmalloc_release, devm_kmalloc_match, ptr); > + if (!old_dr) { > + spin_unlock_irqrestore(&dev->devres_lock, flags); > + devres_free(new_dr); > + WARN(1, "Memory chunk not managed or managed by a different device."); > + return NULL; > + } > + > + replace_dr(dev, &old_dr->node, &new_dr->node); > + > + spin_unlock_irqrestore(&dev->devres_lock, flags); > + > + memcpy(new_dr->data, old_dr->data, devres_data_size(total_old_size)); But new_dr may concurrently gone at this point, no? It means memcpy() should be under spin lock. -- With Best Regards, Andy Shevchenko