efi_pstore: Add a sequence counter to a variable name
[Issue]
Currently, a variable name, which identifies each entry, consists of type, id and ctime.
But if multiple events happens in a short time, a second/third event may fail to log because
efi_pstore can't distinguish each event with current variable name.
[Solution]
A reasonable way to identify all events precisely is introducing a sequence counter to
the variable name.
The sequence counter has already supported in a pstore layer with "oopscount".
So, this patch adds it to a variable name.
Also, it is passed to read/erase callbacks of platform drivers in accordance with
the modification of the variable name.
<before applying this patch>
a variable name of first event: dump-type0-1-12345678
a variable name of second event: dump-type0-1-12345678
type:0
id:1
ctime:12345678
If multiple events happen in a short time, efi_pstore can't distinguish them because
variable names are same among them.
<after applying this patch>
it can be distinguishable by adding a sequence counter as follows.
a variable name of first event: dump-type0-1-1-12345678
a variable name of Second event: dump-type0-1-2-12345678
type:0
id:1
sequence counter: 1(first event), 2(second event)
ctime:12345678
In case of a write callback executed in pstore_console_write(), "0" is added to
an argument of the write callback because it just logs all kernel messages and
doesn't need to care about multiple events.
Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index 3803621..7ad3aae 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -658,13 +658,14 @@
}
static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
- struct timespec *timespec,
+ int *count, struct timespec *timespec,
char **buf, struct pstore_info *psi)
{
efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
struct efivars *efivars = psi->data;
char name[DUMP_NAME_LEN];
int i;
+ int cnt;
unsigned int part, size;
unsigned long time;
@@ -674,8 +675,10 @@
for (i = 0; i < DUMP_NAME_LEN; i++) {
name[i] = efivars->walk_entry->var.VariableName[i];
}
- if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
+ if (sscanf(name, "dump-type%u-%u-%d-%lu",
+ type, &part, &cnt, &time) == 4) {
*id = part;
+ *count = cnt;
timespec->tv_sec = time;
timespec->tv_nsec = 0;
get_var_data_locked(efivars, &efivars->walk_entry->var);
@@ -698,7 +701,8 @@
static int efi_pstore_write(enum pstore_type_id type,
enum kmsg_dump_reason reason, u64 *id,
- unsigned int part, size_t size, struct pstore_info *psi)
+ unsigned int part, int count, size_t size,
+ struct pstore_info *psi)
{
char name[DUMP_NAME_LEN];
efi_char16_t efi_name[DUMP_NAME_LEN];
@@ -725,7 +729,7 @@
return -ENOSPC;
}
- sprintf(name, "dump-type%u-%u-%lu", type, part,
+ sprintf(name, "dump-type%u-%u-%d-%lu", type, part, count,
get_seconds());
for (i = 0; i < DUMP_NAME_LEN; i++)
@@ -746,7 +750,7 @@
return ret;
};
-static int efi_pstore_erase(enum pstore_type_id type, u64 id,
+static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
struct timespec time, struct pstore_info *psi)
{
char name[DUMP_NAME_LEN];
@@ -756,7 +760,7 @@
struct efivar_entry *entry, *found = NULL;
int i;
- sprintf(name, "dump-type%u-%u-%lu", type, (unsigned int)id,
+ sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
time.tv_sec);
spin_lock(&efivars->lock);
@@ -807,7 +811,7 @@
return 0;
}
-static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
+static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, int *count,
struct timespec *timespec,
char **buf, struct pstore_info *psi)
{
@@ -816,12 +820,13 @@
static int efi_pstore_write(enum pstore_type_id type,
enum kmsg_dump_reason reason, u64 *id,
- unsigned int part, size_t size, struct pstore_info *psi)
+ unsigned int part, int count, size_t size,
+ struct pstore_info *psi)
{
return 0;
}
-static int efi_pstore_erase(enum pstore_type_id type, u64 id,
+static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
struct timespec time, struct pstore_info *psi)
{
return 0;