Messages in this thread Patch in this message | | | From | Seiji Aguchi <> | Subject | [RFC][PATCH v2 3/3] efi_pstore: Skip scheduling a workqueue in cases other than oops | Date | Mon, 20 Aug 2012 19:15:55 +0000 |
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[Problem] efi_pstore creates sysfs files when logging kernel messages to NVRAM. Currently, the sysfs files are updated in a workqueue which is registered in a write callback.
On the other hand, a situation which users need the sysfs files is just oops case because a system will be down and they can't access to sysfs files in other cases like panic, reboot or emergency_restart.
Also, if kernel panics due to a bug of workqueue operations and a write callback of efi_pstore is called in panic case, efi_pstore may fail due to a failure of schedule_work(). And panic_notifier_chain()/emergency_restart() is not kicked if efi_pstore fails. This may cause user's unwanted result.
[Patch Description] This patch skips a registration of a workqueue in a write callback in cases other than oops.
Also, a logic of erase callback is freshly created instead of sharing with a write callback because the sysfs operation is kicked in just oops case in a write callback and an erase callback doesn't work without any change. By separating a logic to a write callback, an erase callback works correctly.
Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com> --- drivers/firmware/efivars.c | 53 ++++++++++++++++++++++++++++++++++++++++++- 1 files changed, 51 insertions(+), 2 deletions(-)
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c index 8717ea9..4811abb 100644 --- a/drivers/firmware/efivars.c +++ b/drivers/firmware/efivars.c @@ -747,7 +747,11 @@ static int efi_pstore_write(enum pstore_type_id type, spin_unlock_irqrestore(&efivars->lock, flags); - schedule_work(&efivar_work); + /* + * The user may want to see an entry for this write in sysfs. + */ + if (reason == KMSG_DUMP_OOPS) + schedule_work(&efivar_work); *id = part; return ret; @@ -756,7 +760,52 @@ static int efi_pstore_write(enum pstore_type_id type, static int efi_pstore_erase(enum pstore_type_id type, u64 id, struct pstore_info *psi) { - efi_pstore_write(type, 0, &id, (unsigned int)id, 0, psi); + char stub_name[DUMP_NAME_LEN]; + efi_char16_t efi_name[DUMP_NAME_LEN]; + efi_guid_t vendor = LINUX_EFI_CRASH_GUID; + struct efivars *efivars = psi->data; + struct efivar_entry *entry, *found = NULL; + int i; + unsigned long flags; + + sprintf(stub_name, "dump-type%u-%llu-", type, id); + + spin_lock_irqsave(&efivars->lock, flags); + + for (i = 0; i < DUMP_NAME_LEN; i++) + efi_name[i] = stub_name[i]; + + /* + * Clean up any entries with the same name + */ + + list_for_each_entry(entry, &efivars->list, list) { + get_var_data_locked(efivars, &entry->var); + + if (efi_guidcmp(entry->var.VendorGuid, vendor)) + continue; + if (utf16_strncmp(entry->var.VariableName, efi_name, + utf16_strlen(efi_name))) + continue; + /* Needs to be a prefix */ + if (entry->var.VariableName[utf16_strlen(efi_name)] == 0) + continue; + + /* found */ + found = entry; + efivars->ops->set_variable(entry->var.VariableName, + &entry->var.VendorGuid, + PSTORE_EFI_ATTRIBUTES, + 0, NULL); + } + + if (found) + list_del(&found->list); + + spin_unlock_irqrestore(&efivars->lock, flags); + + if (found) + efivar_unregister(found); return 0; } -- 1.7.1
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