Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754837Ab2KEUhk (ORCPT ); Mon, 5 Nov 2012 15:37:40 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:55051 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754009Ab2KEUhj (ORCPT ); Mon, 5 Nov 2012 15:37:39 -0500 Date: Mon, 5 Nov 2012 12:37:38 -0800 From: Andrew Morton To: Xi Wang Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: fix NULL checking in dma_pool_create() Message-Id: <20121105123738.0a0490a7.akpm@linux-foundation.org> In-Reply-To: <1352097996-25808-1-git-send-email-xi.wang@gmail.com> References: <1352097996-25808-1-git-send-email-xi.wang@gmail.com> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; 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 Content-Length: 1126 Lines: 30 On Mon, 5 Nov 2012 01:46:36 -0500 Xi Wang wrote: > First, `dev' is dereferenced in dev_to_node(dev), suggesting that it > must be non-null. Later `dev' is checked against NULL, suggesting > the opposite. This patch adds a NULL check before its use. > > ... > > @@ -159,7 +160,9 @@ struct dma_pool *dma_pool_create(const char *name, struct device *dev, > return NULL; > } > > - retval = kmalloc_node(sizeof(*retval), GFP_KERNEL, dev_to_node(dev)); > + node = dev ? dev_to_node(dev) : -1; > + > + retval = kmalloc_node(sizeof(*retval), GFP_KERNEL, node); > if (!retval) > return retval; Well, the dma_pool_create() kerneldoc does not describe dev==NULL to be acceptable usage and given the lack of oops reports, we can assume that no code is calling this function with dev==NULL. So I think we can just remove the code which handles dev==NULL? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/