Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754895AbaFNPA0 (ORCPT ); Sat, 14 Jun 2014 11:00:26 -0400 Received: from mail-ie0-f179.google.com ([209.85.223.179]:43397 "EHLO mail-ie0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754753AbaFNPAW (ORCPT ); Sat, 14 Jun 2014 11:00:22 -0400 MIME-Version: 1.0 In-Reply-To: References: <539A91E2.7000606@gmail.com> From: Grant Likely Date: Sat, 14 Jun 2014 16:00:02 +0100 X-Google-Sender-Auth: RDDliUg6rxrKOJ9WRNdN4AhF6w0 Message-ID: Subject: Re: [RFC PATCH] OF: fix of_find_node_by_path() assumption that of_allnodes is root To: Rob Herring Cc: Frank Rowand , Pantelis Antoniou , Rob Herring , "devicetree@vger.kernel.org" , Linux Kernel list Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 13, 2014 at 4:06 PM, Grant Likely wrote: > On Fri, Jun 13, 2014 at 2:52 PM, Rob Herring wrote: >> On Fri, Jun 13, 2014 at 12:53 AM, Frank Rowand wrote: >>> From: Frank Rowand >>> >>> Pantelis Antoniou reports that of_find_node_by_path() is borked because >>> of_allnodes is not guaranteed to contain the root of the tree after using >>> any of the dynamic update functions because some other nodes ends up as >>> of_allnodes. >>> >>> Fixes: c22e650e66b8 of: Make of_find_node_by_path() handle /aliases >> >> Is it not possible to do a fix in of_find_node_by_path instead? I just >> wonder if this could have any other unintended side-effects on >> of_attach_node's behavior. > > Given that I'm going to replace the custom list with list_head which > makes this problem go away, I think this solution is fine. > > Acked-by: Grant Likely That said, the following might be better because it would guarantee that children always appear after parents... >> Rob >> >>> >>> Signed-off-by: Frank Rowand >>> --- >>> >>> >>> Pantelis, >>> >>> Can you test whether the problem you reported in irc? >>> >>> This patch has not been tested, not even compile tested. >>> >>> >>> drivers/of/base.c | 8 6 + 2 - 0 ! >>> 1 file changed, 6 insertions(+), 2 deletions(-) >>> >>> Index: b/drivers/of/base.c >>> =================================================================== >>> --- a/drivers/of/base.c >>> +++ b/drivers/of/base.c >>> @@ -1948,6 +1948,9 @@ int of_reconfig_notify(unsigned long act >>> >>> /** >>> * of_attach_node - Plug a device node into the tree and global list. >>> + * >>> + * Put the device node after of_allnodes in the global list so that >>> + * of_allnodes remains the root. >>> */ >>> int of_attach_node(struct device_node *np) >>> { >>> @@ -1958,11 +1961,12 @@ int of_attach_node(struct device_node *n >>> if (rc) >>> return rc; >>> >>> + BUG_ON(!of_allnodes); >>> raw_spin_lock_irqsave(&devtree_lock, flags); >>> np->sibling = np->parent->child; >>> - np->allnext = of_allnodes; >>> + np->allnext = of_allnodes->allnext; np->allnext = np->parent->allnext; np->parent->allnext = np; >>> np->parent->child = np; >>> - of_allnodes = np; >>> + of_allnodes->allnext = np; >>> of_node_clear_flag(np, OF_DETACHED); >>> raw_spin_unlock_irqrestore(&devtree_lock, flags); >>> -- 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/