Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030691Ab2HWS5O (ORCPT ); Thu, 23 Aug 2012 14:57:14 -0400 Received: from usindpps06.hds.com ([207.126.252.19]:48570 "EHLO usindpps06.hds.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934243Ab2HWS4x convert rfc822-to-8bit (ORCPT ); Thu, 23 Aug 2012 14:56:53 -0400 From: Seiji Aguchi To: "Luck, Tony (tony.luck@intel.com)" CC: "dle-develop@lists.sourceforge.net" , Satoru Moriya , "Matthew Garrett (mjg@redhat.com)" , "dzickus@redhat.com" , Mike Waychison , "linux-kernel@vger.kernel.org" Subject: RE: [RFC][PATCH v4 0/3] make efivars/efi_pstore interrupt-safe Thread-Topic: [RFC][PATCH v4 0/3] make efivars/efi_pstore interrupt-safe Thread-Index: Ac1/3B4XXy3iKFABRLu93LVB8DzCQQBhKvgw Date: Thu, 23 Aug 2012 18:56:38 +0000 Message-ID: Accept-Language: ja-JP, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.74.43.113] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.7.7855,1.0.260,0.0.0000 definitions=2012-08-23_06:2012-08-23,2012-08-23,1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_policy_notspam policy=outbound_policy score=0 spamscore=0 ipscore=0 suspectscore=1 phishscore=0 bulkscore=2 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=6.0.2-1203120001 definitions=main-1208230193 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3141 Lines: 76 Tony, Cloud you please review this patchset? Seiji > -----Original Message----- > From: Seiji Aguchi > Sent: Tuesday, August 21, 2012 4:35 PM > To: 'Mike Waychison'; 'linux-kernel@vger.kernel.org'; 'Luck, Tony (tony.luck@intel.com)'; 'Matthew Garrett (mjg@redhat.com)'; > 'dzickus@redhat.com' > Cc: 'dle-develop@lists.sourceforge.net'; Satoru Moriya > Subject: [RFC][PATCH v4 0/3] make efivars/efi_pstore interrupt-safe > > Changelog > v3 -> v4 > - Patch 2/3 > Move cancel_work_sync() above an efi_enabled test in efivars_exit(). > > v2 -> v3 > - Patch 1/3 > Replace spin_lock_irqsave/spin_unlock_irqrestore with spin_lock_irq/spin_unlock_irq in efivars_unregister(), > efivar_create(), efivar_store_raw() and efivar_delete() which are called in a process context. > > - Patch 2/3 > Change a name of delete_sysfs_entry() to delete_all_stale_sysfs_entries(). > Also, don't release an efivar->lock while searching efivar->list in delete_all_stale_sysfs_entries(). > > - Patch 3/3 > Remove a logic in efi_pstore_erase() which freshly created in patch v2. > > v1 -> v2 > - Patch 1/3 > Add spin_lock_irq/spin_unlock_irq to open/close callbacks of efi_pstore > instead of moving spin_locks to a read callback. > > - Patch 2/3 > Replace a periodical timer with schedule_work(). > > - Patch 3/3 > freshly create to kick a workqueue in oops case only. > > [Problem] > There are following problems related to an interrupt context in efivar/efi_pstore. > > Currently, efivars enables interrupt while taking efivars->lock. > So, there is a risk to be deadlocking in a write callback of efi_pstore if kernel panics in interrupt context while taking efi_lock. > > Also, efi_pstore creates sysfs entries ,which enable users to access to NVRAM, in a write callback. > If a kernel panic happens in interrupt contexts, pstore may fail because it could sleep due to dynamic memory allocations during > creating sysfs entries. > > To resolve the problems above, a goal of this patchset is making efivars/efi_pstore interrupt-safe. > > [Patch Description] > Patch 1/3 efivars: Disable external interrupt while holding efivars->lock > This patch replaces spin_lock/spin_unlock with spin_lock_irqsave/spin_lock_irqrestore to make efivars interrupt safe > > Patch 2/3 efi_pstore: Introducing workqueue updating sysfs entries > This patch removes sysfs operations from write callback by introducing a workqueue updating sysfs entries > > Patch 3/3 efi_pstore: Skiping scheduling a workqueue in cases other than oops > This patch restricts a schedule of a workqueue in case where users erase entries or oops happen which is truly needed for users. > > drivers/firmware/efivars.c | 167 +++++++++++++++++++++++++++++++++++-------- > include/linux/efi.h | 3 +- > 2 files changed, 138 insertions(+), 32 deletions(-) > > > -- 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/