From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965611AbXAXCFu (ORCPT ); Tue, 23 Jan 2007 21:05:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965612AbXAXCFu (ORCPT ); Tue, 23 Jan 2007 21:05:50 -0500 Received: from smtp106.sbc.mail.mud.yahoo.com ([68.142.198.205]:38045 "HELO smtp106.sbc.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S965611AbXAXCFt (ORCPT ); Tue, 23 Jan 2007 21:05:49 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=pacbell.net; h=Received:X-YMail-OSG:From:To:Subject:Date:User-Agent:Cc:References:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding:Content-Disposition:Message-Id; b=U8L30gOHHijhXZZbFCglrJ5qnpgnrmfiBZVxROCIKXps9ICJxDifssFsMffigKrKHTwdrEv2CMkgYnt3E/28b5gp21nmZ2EE/Zh5eVTcJA6AyxjDuBlIrkvH6cYkSThbcYaT6MwB2vfhX4S2QuKsa8NAHxNqrsBVw9vCSabCN98= ; X-YMail-OSG: SuqQQa4VM1msDR_U5Mc7Mh__qxkpa0eZzJUDYUwyy3bsUh0kpQx.s5PB9JNW7GY.zutLtyouFaP6kXlATcBs9kQWzT0fMHB8jMwcwgqFNLyJ4E2CPBo- From: David Brownell To: Atsushi Nemoto Subject: Re: [PATCH 2.6.20-rc5] SPI: alternative fix for spi_busnum_to_master Date: Tue, 23 Jan 2007 15:43:56 -0800 User-Agent: KMail/1.7.1 Cc: linux-kernel@vger.kernel.org, hcegtvedt@atmel.com, akpm@osdl.org References: <200701221412.02452.david-b@pacbell.net> <200701230742.15531.david-b@pacbell.net> <20070124.010741.130240814.anemo@mba.ocn.ne.jp> In-Reply-To: <20070124.010741.130240814.anemo@mba.ocn.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200701231543.56669.david-b@pacbell.net> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday 23 January 2007 8:07 am, Atsushi Nemoto wrote: > On Tue, 23 Jan 2007 07:42:15 -0800, David Brownell wrote: > > > Indeed the check can be omitted. Should I send a new patch just > > > moving class_device_get() into "if (master->bus_num == bus_num)" > > > block? > > > > Yes, please. > > OK, here is. This patch uses spi_master_get() instead of > class_device_get(). Much better. This should be merged for 2.6.20 ... > > > Subject: SPI: alternative fix for spi_busnum_to_master > > If a SPI master device exists, udev (udevtrigger) causes kernel crash, > due to wrong kobj pointer in kobject_uevent_env(). This problem was > not in 2.6.19. > > The backtrace (on MIPS) was: > [<8024db6c>] kobject_uevent_env+0x54c/0x5e8 > [<802a8264>] store_uevent+0x1c/0x3c (in drivers/class.c) > [<801cb14c>] subsys_attr_store+0x2c/0x50 > [<801cb80c>] flush_write_buffer+0x38/0x5c > [<801cb900>] sysfs_write_file+0xd0/0x190 > [<80181444>] vfs_write+0xc4/0x1a0 > [<80181cdc>] sys_write+0x54/0xa0 > [<8010dae4>] stack_done+0x20/0x3c > > flush_write_buffer() passes kobject of spi_master_class.subsys to > subsys_addr_store(), then subsys_addr_store() passes a pointer to a > struct subsystem to store_uevent() which expects a pointer to a struct > class_device. The problem seems subsys_attr_store() called instead of > class_device_attr_store(). > > This mismatch was caused by commit > 3bd0f6943520e459659d10f3282285e43d3990f1, which overrides kset of > master class. This made spi_master_class.subsys.kset.ktype NULL so > subsys_sysfs_ops is used instead of class_dev_sysfs_ops. > > The commit was to fix spi_busnum_to_master(). Here is a patch fixes > this function in other way, just searching children list of > class_device. > > Signed-off-by: Atsushi Nemoto > --- > diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c > index 270e621..6307428 100644 > --- a/drivers/spi/spi.c > +++ b/drivers/spi/spi.c > @@ -366,7 +366,6 @@ spi_alloc_master(struct device *dev, uns > > class_device_initialize(&master->cdev); > master->cdev.class = &spi_master_class; > - kobj_set_kset_s(&master->cdev, spi_master_class.subsys); > master->cdev.dev = get_device(dev); > spi_master_set_devdata(master, &master[1]); > > @@ -466,14 +465,20 @@ EXPORT_SYMBOL_GPL(spi_unregister_master) > */ > struct spi_master *spi_busnum_to_master(u16 bus_num) > { > - char name[9]; > - struct kobject *bus; > - > - snprintf(name, sizeof name, "spi%u", bus_num); > - bus = kset_find_obj(&spi_master_class.subsys.kset, name); > - if (bus) > - return container_of(bus, struct spi_master, cdev.kobj); > - return NULL; > + struct class_device *cdev; > + struct spi_master *master = NULL; > + struct spi_master *m; > + > + down(&spi_master_class.sem); > + list_for_each_entry(cdev, &spi_master_class.children, node) { > + m = container_of(cdev, struct spi_master, cdev); > + if (m->bus_num == bus_num) { > + master = spi_master_get(m); > + break; > + } > + } > + up(&spi_master_class.sem); > + return master; > } > EXPORT_SYMBOL_GPL(spi_busnum_to_master); > >