From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755418Ab3JJXGH (ORCPT ); Thu, 10 Oct 2013 19:06:07 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:38890 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752996Ab3JJXGF (ORCPT ); Thu, 10 Oct 2013 19:06:05 -0400 Date: Thu, 10 Oct 2013 16:06:03 -0700 From: Andrew Morton To: Joe Perches Cc: "sangjung.woo" , Alessandro Rubini , Russell King , rtc-linux@googlegroups.com, linux-kernel@vger.kernel.org, Tejun Heo , Greg KH Subject: Re: [PATCH] rtc: pl030: Use devm_kzalloc() instead of kmalloc() Message-Id: <20131010160603.1489fe054c2bdc0a0eb9460f@linux-foundation.org> In-Reply-To: <1381294767.2040.5.camel@joe-AO722> References: <1381291240-23727-1-git-send-email-sangjung.woo@samsung.com> <1381291649.2040.1.camel@joe-AO722> <5254DD64.4090205@samsung.com> <1381294767.2040.5.camel@joe-AO722> X-Mailer: Sylpheed 3.2.0beta5 (GTK+ 2.24.10; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 08 Oct 2013 21:59:27 -0700 Joe Perches wrote: > I was a bit surprised to find there isn't a devm_kmalloc. Yes, the unconditional memset is silly. Especially when the function has a handy gfp_t and could be passed __GFP_ZERO. The comment says "managed kzalloc/kfree for device drivers, no kmalloc, always use kzalloc". There's no explanation for this - it looks like some ideological thing. --- a/drivers/base/devres.c~a +++ a/drivers/base/devres.c @@ -91,7 +91,8 @@ static __always_inline struct devres * a if (unlikely(!dr)) return NULL; - memset(dr, 0, tot_size); + if (gfp & __GFP_ZERO) + memset(dr, 0, tot_size); INIT_LIST_HEAD(&dr->node.entry); dr->node.release = release; return dr; @@ -770,7 +771,7 @@ static int devm_kzalloc_match(struct dev * RETURNS: * Pointer to allocated memory on success, NULL on failure. */ -void * devm_kzalloc(struct device *dev, size_t size, gfp_t gfp) +static void *__devm_kzalloc(struct device *dev, size_t size, gfp_t gfp) { struct devres *dr; @@ -783,8 +784,19 @@ void * devm_kzalloc(struct device *dev, devres_add(dev, dr->data); return dr->data; } + +void *devm_kzalloc(struct device *dev, size_t size, gfp_t gfp) +{ + return __devm_kzalloc(dev, size, gfp | __GFP_ZERO); +} EXPORT_SYMBOL_GPL(devm_kzalloc); +void *devm_kmalloc(struct device *dev, size_t size, gfp_t gfp) +{ + return __devm_kzalloc(dev, size, gfp); +} +EXPORT_SYMBOL_GPL(devm_kmalloc); + /** * devm_kfree - Resource-managed kfree * @dev: Device this memory belongs to --- a/include/linux/device.h~a +++ a/include/linux/device.h @@ -602,8 +602,9 @@ extern void devres_close_group(struct de extern void devres_remove_group(struct device *dev, void *id); extern int devres_release_group(struct device *dev, void *id); -/* managed kzalloc/kfree for device drivers, no kmalloc, always use kzalloc */ +/* managed kmalloc/kzalloc/kfree for device drivers */ extern void *devm_kzalloc(struct device *dev, size_t size, gfp_t gfp); +extern void *devm_kmalloc(struct device *dev, size_t size, gfp_t gfp); extern void devm_kfree(struct device *dev, void *p); void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res); _