diff options
Diffstat (limited to 'drivers/firmware/efi/efi-pstore.c')
| -rw-r--r-- | drivers/firmware/efi/efi-pstore.c | 150 |
1 files changed, 138 insertions, 12 deletions
diff --git a/drivers/firmware/efi/efi-pstore.c b/drivers/firmware/efi/efi-pstore.c index 202d2c85ba2e..bf8dd3d5bee7 100644 --- a/drivers/firmware/efi/efi-pstore.c +++ b/drivers/firmware/efi/efi-pstore.c @@ -18,14 +18,12 @@ module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644); static int efi_pstore_open(struct pstore_info *psi) { - efivar_entry_iter_begin(); psi->data = NULL; return 0; } static int efi_pstore_close(struct pstore_info *psi) { - efivar_entry_iter_end(); psi->data = NULL; return 0; } @@ -78,19 +76,124 @@ static int efi_pstore_read_func(struct efivar_entry *entry, void *data) __efivar_entry_get(entry, &entry->var.Attributes, &entry->var.DataSize, entry->var.Data); size = entry->var.DataSize; + memcpy(*cb_data->buf, entry->var.Data, + (size_t)min_t(unsigned long, EFIVARS_DATA_SIZE_MAX, size)); - *cb_data->buf = kmalloc(size, GFP_KERNEL); - if (*cb_data->buf == NULL) - return -ENOMEM; - memcpy(*cb_data->buf, entry->var.Data, size); return size; } +/** + * efi_pstore_scan_sysfs_enter + * @entry: scanning entry + * @next: next entry + * @head: list head + */ +static void efi_pstore_scan_sysfs_enter(struct efivar_entry *pos, + struct efivar_entry *next, + struct list_head *head) +{ + pos->scanning = true; + if (&next->list != head) + next->scanning = true; +} + +/** + * __efi_pstore_scan_sysfs_exit + * @entry: deleting entry + * @turn_off_scanning: Check if a scanning flag should be turned off + */ +static inline void __efi_pstore_scan_sysfs_exit(struct efivar_entry *entry, + bool turn_off_scanning) +{ + if (entry->deleting) { + list_del(&entry->list); + efivar_entry_iter_end(); + efivar_unregister(entry); + efivar_entry_iter_begin(); + } else if (turn_off_scanning) + entry->scanning = false; +} + +/** + * efi_pstore_scan_sysfs_exit + * @pos: scanning entry + * @next: next entry + * @head: list head + * @stop: a flag checking if scanning will stop + */ +static void efi_pstore_scan_sysfs_exit(struct efivar_entry *pos, + struct efivar_entry *next, + struct list_head *head, bool stop) +{ + __efi_pstore_scan_sysfs_exit(pos, true); + if (stop) + __efi_pstore_scan_sysfs_exit(next, &next->list != head); +} + +/** + * efi_pstore_sysfs_entry_iter + * + * @data: function-specific data to pass to callback + * @pos: entry to begin iterating from + * + * You MUST call efivar_enter_iter_begin() before this function, and + * efivar_entry_iter_end() afterwards. + * + * It is possible to begin iteration from an arbitrary entry within + * the list by passing @pos. @pos is updated on return to point to + * the next entry of the last one passed to efi_pstore_read_func(). + * To begin iterating from the beginning of the list @pos must be %NULL. + */ +static int efi_pstore_sysfs_entry_iter(void *data, struct efivar_entry **pos) +{ + struct efivar_entry *entry, *n; + struct list_head *head = &efivar_sysfs_list; + int size = 0; + + if (!*pos) { + list_for_each_entry_safe(entry, n, head, list) { + efi_pstore_scan_sysfs_enter(entry, n, head); + + size = efi_pstore_read_func(entry, data); + efi_pstore_scan_sysfs_exit(entry, n, head, size < 0); + if (size) + break; + } + *pos = n; + return size; + } + + list_for_each_entry_safe_from((*pos), n, head, list) { + efi_pstore_scan_sysfs_enter((*pos), n, head); + + size = efi_pstore_read_func((*pos), data); + efi_pstore_scan_sysfs_exit((*pos), n, head, size < 0); + if (size) + break; + } + *pos = n; + return size; +} + +/** + * efi_pstore_read + * + * This function returns a size of NVRAM entry logged via efi_pstore_write(). + * The meaning and behavior of efi_pstore/pstore are as below. + * + * size > 0: Got data of an entry logged via efi_pstore_write() successfully, + * and pstore filesystem will continue reading subsequent entries. + * size == 0: Entry was not logged via efi_pstore_write(), + * and efi_pstore driver will continue reading subsequent entries. + * size < 0: Failed to get data of entry logging via efi_pstore_write(), + * and pstore will stop reading entry. + */ static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, int *count, struct timespec *timespec, char **buf, struct pstore_info *psi) { struct pstore_read_data data; + ssize_t size; data.id = id; data.type = type; @@ -98,8 +201,17 @@ static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, data.timespec = timespec; data.buf = buf; - return __efivar_entry_iter(efi_pstore_read_func, &efivar_sysfs_list, &data, - (struct efivar_entry **)&psi->data); + *data.buf = kzalloc(EFIVARS_DATA_SIZE_MAX, GFP_KERNEL); + if (!*data.buf) + return -ENOMEM; + + efivar_entry_iter_begin(); + size = efi_pstore_sysfs_entry_iter(&data, + (struct efivar_entry **)&psi->data); + efivar_entry_iter_end(); + if (size <= 0) + kfree(*data.buf); + return size; } static int efi_pstore_write(enum pstore_type_id type, @@ -170,9 +282,17 @@ static int efi_pstore_erase_func(struct efivar_entry *entry, void *data) return 0; } + if (entry->scanning) { + /* + * Skip deletion because this entry will be deleted + * after scanning is completed. + */ + entry->deleting = true; + } else + list_del(&entry->list); + /* found */ __efivar_entry_delete(entry); - list_del(&entry->list); return 1; } @@ -200,10 +320,12 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count, efivar_entry_iter_begin(); found = __efivar_entry_iter(efi_pstore_erase_func, &efivar_sysfs_list, &edata, &entry); - efivar_entry_iter_end(); - if (found) + if (found && !entry->scanning) { + efivar_entry_iter_end(); efivar_unregister(entry); + } else + efivar_entry_iter_end(); return 0; } @@ -236,7 +358,11 @@ static __init int efivars_pstore_init(void) efi_pstore_info.bufsize = 1024; spin_lock_init(&efi_pstore_info.buf_lock); - pstore_register(&efi_pstore_info); + if (pstore_register(&efi_pstore_info)) { + kfree(efi_pstore_info.buf); + efi_pstore_info.buf = NULL; + efi_pstore_info.bufsize = 0; + } return 0; } |