Matthew, Could you please review this patchset? I talked to Tony about it in Plumbers conference last week and he told that your review is needed because it is efi-specific. Seiji > -----Original Message----- > From: linux-kernel-owner@xxxxxxxxxxxxxxx [mailto:linux-kernel-owner@xxxxxxxxxxxxxxx] On Behalf Of Seiji Aguchi > Sent: Tuesday, September 04, 2012 6:06 PM > To: Mike Waychison; linux-kernel@xxxxxxxxxxxxxxx; Luck, Tony (tony.luck@xxxxxxxxx); Matthew Garrett (mjg@xxxxxxxxxx); > dzickus@xxxxxxxxxx; linux-efi@xxxxxxxxxxxxxxx > Cc: dle-develop@xxxxxxxxxxxxxxxxxxxxx; Satoru Moriya > Subject: [RESEND][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@xxxxxxxxxxxxxxx More > majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
