From patchwork Mon Aug 24 17:38:57 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bartosz Golaszewski X-Patchwork-Id: 11733849 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A79E813B1 for ; Mon, 24 Aug 2020 17:39:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8A6D920702 for ; Mon, 24 Aug 2020 17:39:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=bgdev-pl.20150623.gappssmtp.com header.i=@bgdev-pl.20150623.gappssmtp.com header.b="tJE4GjPT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726873AbgHXRjP (ORCPT ); Mon, 24 Aug 2020 13:39:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35248 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726645AbgHXRjH (ORCPT ); Mon, 24 Aug 2020 13:39:07 -0400 Received: from mail-wm1-x343.google.com (mail-wm1-x343.google.com [IPv6:2a00:1450:4864:20::343]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B3D38C061755 for ; Mon, 24 Aug 2020 10:39:06 -0700 (PDT) Received: by mail-wm1-x343.google.com with SMTP id a65so5682983wme.5 for ; Mon, 24 Aug 2020 10:39:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bgdev-pl.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=IM4nLu2vwj8edbMPLQ6Y8SGdHl2C8QezmkyULndrgow=; b=tJE4GjPTi870tfWVtDFHFf2cNVWrY8ls91g2f39HwQ6Sln7wRhLo0Ucy0F0ucsD93l ZY9K6VH1i/NvXk4V48YcjhOddjht3ncPVlEBJ9KLbvQNr624Y4qpNN97kFza45urAW8g s7L3L5Ehs0JN5olEsCDQw7QSQgL7tDckg4ie4J7ICylKkEKyMiD2fqaMUliFgz97VXId aNi2UnflPTs3i9nP1Kb1kQfuj+h5uDw65iMz/KehNWBE/L/wOEuipTmAcRnlxH+P2Sd6 3/oRijwwVIv366lbDRPkVi+ptmnwPtt7lvT9dthZVHQfzGj9UU0TRj2NhD1m4WygFU7f PZeQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=IM4nLu2vwj8edbMPLQ6Y8SGdHl2C8QezmkyULndrgow=; b=gjKvvp1IcwGhQIP3/hjnZbDkpgsYU2zURLfj5q5yfY/3BHgpaK2PwVTQqQAA4MOJ0f /5tPDFtzvbpsT/CvTmeob7AL4TWHQWDnWlnNXgfLRn2+mv7B0mh5dCCWcpz1DP5zzxX7 5JtISnnMbuARySIWr2IoykrJquUX4RmQl5K+LY0d6qgCM23z5ohph6cWO98Ji4/EnJeb fHLTZXvbYaBbYRNmGAmslGmBQ2koTeRmt8Pn9QNMcqvpsIFAlUPu1w5DtrZEgG2RcbUx U5IHOjBKNlDHNvAjKESgQx22ugGJeyk+PhMqGrhKyq/UsxII+2ajevEjcwhoBo9MAdOE Fn2Q== X-Gm-Message-State: AOAM531s3Ie7cnGYTneruCE4/C78Jfzbx2BV+LxOilvd3w/j9V7BaBHp WCzvhHb+N7O1IK7gntiUuBzYng== X-Google-Smtp-Source: ABdhPJwFab+HKnem/w5mC3GHxWaWpYuvz+TPfeQHLz7XZaMrgpQ22emRmJcCSLxR8HtXpsXYOWvtQg== X-Received: by 2002:a1c:e288:: with SMTP id z130mr404342wmg.32.1598290744509; Mon, 24 Aug 2020 10:39:04 -0700 (PDT) Received: from debian-brgl.home (lfbn-nic-1-68-20.w2-15.abo.wanadoo.fr. [2.15.159.20]) by smtp.gmail.com with ESMTPSA id y24sm471977wmi.17.2020.08.24.10.39.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Aug 2020 10:39:04 -0700 (PDT) From: Bartosz Golaszewski To: Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , Michal Simek , Greg Kroah-Hartman , Guenter Roeck , Andy Shevchenko Cc: linux-iio@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Bartosz Golaszewski Subject: [PATCH v9 1/3] devres: provide devm_krealloc() Date: Mon, 24 Aug 2020 19:38:57 +0200 Message-Id: <20200824173859.4910-2-brgl@bgdev.pl> X-Mailer: git-send-email 2.26.1 In-Reply-To: <20200824173859.4910-1-brgl@bgdev.pl> References: <20200824173859.4910-1-brgl@bgdev.pl> MIME-Version: 1.0 Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org 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(). Signed-off-by: Bartosz Golaszewski Reviewed-by: Andy Shevchenko --- .../driver-api/driver-model/devres.rst | 1 + drivers/base/devres.c | 105 ++++++++++++++++++ include/linux/device.h | 2 + 3 files changed, 108 insertions(+) diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst index eaaaafc21134..f318a5c0033c 100644 --- a/Documentation/driver-api/driver-model/devres.rst +++ b/Documentation/driver-api/driver-model/devres.rst @@ -354,6 +354,7 @@ MEM devm_kmalloc() devm_kmalloc_array() devm_kmemdup() + devm_krealloc() devm_kstrdup() devm_kvasprintf() devm_kzalloc() diff --git a/drivers/base/devres.c b/drivers/base/devres.c index ed615d3b9cf1..586e9a75c840 100644 --- a/drivers/base/devres.c +++ b/drivers/base/devres.c @@ -126,6 +126,14 @@ static void add_dr(struct device *dev, struct devres_node *node) list_add_tail(&node->entry, &dev->devres_head); } +static void replace_dr(struct device *dev, + struct devres_node *old, struct devres_node *new) +{ + devres_log(dev, old, "REPLACE"); + BUG_ON(!list_empty(&new->entry)); + list_replace(&old->entry, &new->entry); +} + #ifdef CONFIG_DEBUG_DEVRES void * __devres_alloc_node(dr_release_t release, size_t size, gfp_t gfp, int nid, const char *name) @@ -837,6 +845,103 @@ void *devm_kmalloc(struct device *dev, size_t size, gfp_t gfp) } EXPORT_SYMBOL_GPL(devm_kmalloc); +/** + * devm_krealloc - Resource-managed krealloc() + * @dev: Device to re-allocate memory for + * @ptr: Pointer to the memory chunk to re-allocate + * @new_size: New allocation size + * @gfp: Allocation gfp flags + * + * Managed krealloc(). Resizes the memory chunk allocated with devm_kmalloc(). + * Behaves similarly to regular krealloc(): if @ptr is NULL or ZERO_SIZE_PTR, + * it's the equivalent of devm_kmalloc(). If new_size is zero, it frees the + * previously allocated memory and returns ZERO_SIZE_PTR. This function doesn't + * change the order in which the release callback for the re-alloc'ed devres + * will be called (except when falling back to devm_kmalloc() or when freeing + * resources when new_size is zero). The contents of the memory are preserved + * up to the lesser of new and old sizes. + */ +void *devm_krealloc(struct device *dev, void *ptr, size_t new_size, gfp_t gfp) +{ + size_t total_new_size, total_old_size; + struct devres *old_dr, *new_dr; + unsigned long flags; + + if (unlikely(!new_size)) { + devm_kfree(dev, ptr); + return ZERO_SIZE_PTR; + } + + if (unlikely(ZERO_OR_NULL_PTR(ptr))) + return devm_kmalloc(dev, new_size, gfp); + + if (WARN_ON(is_kernel_rodata((unsigned long)ptr))) + /* + * We cannot reliably realloc a const string returned by + * devm_kstrdup_const(). + */ + return NULL; + + if (!check_dr_size(new_size, &total_new_size)) + return NULL; + + total_old_size = ksize(container_of(ptr, struct devres, data)); + if (total_old_size == 0) { + WARN(1, "Pointer doesn't point to dynamically allocated memory."); + return NULL; + } + + /* + * If new size is smaller or equal to the actual number of bytes + * allocated previously - just return the same pointer. + */ + if (total_new_size <= total_old_size) + return ptr; + + /* + * Otherwise: allocate new, larger chunk. We need to allocate before + * taking the lock as most probably the caller uses GFP_KERNEL. + */ + new_dr = alloc_dr(devm_kmalloc_release, + total_new_size, gfp, dev_to_node(dev)); + if (!new_dr) + return NULL; + + /* + * The spinlock protects the linked list against concurrent + * modifications but not the resource itself. + */ + 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); + kfree(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); + + /* + * We can copy the memory contents after releasing the lock as we're + * no longer modyfing the list links. + */ + memcpy(new_dr->data, old_dr->data, + total_old_size - offsetof(struct devres, data)); + /* + * Same for releasing the old devres - it's now been removed from the + * list. This is also the reason why we must not use devm_kfree() - the + * links are no longer valid. + */ + kfree(old_dr); + + return new_dr->data; +} +EXPORT_SYMBOL_GPL(devm_krealloc); + /** * devm_kstrdup - Allocate resource managed space and * copy an existing string into that. diff --git a/include/linux/device.h b/include/linux/device.h index ca18da4768e3..5da7d5f0a7ff 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -206,6 +206,8 @@ int devres_release_group(struct device *dev, void *id); /* managed devm_k.alloc/kfree for device drivers */ void *devm_kmalloc(struct device *dev, size_t size, gfp_t gfp) __malloc; +void *devm_krealloc(struct device *dev, void *ptr, size_t size, + gfp_t gfp) __must_check; __printf(3, 0) char *devm_kvasprintf(struct device *dev, gfp_t gfp, const char *fmt, va_list ap) __malloc; __printf(3, 4) char *devm_kasprintf(struct device *dev, gfp_t gfp,