From 755d4fe46529018ae45bc7c86df682de45ace764 Mon Sep 17 00:00:00 2001 From: Seiji Aguchi Date: Mon, 26 Nov 2012 16:07:44 -0800 Subject: 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. 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. 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 Acked-by: Rafael J. Wysocki Acked-by: Mike Waychison Signed-off-by: Tony Luck --- drivers/firmware/efivars.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) (limited to 'drivers/firmware') diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c index 3803621c0d45..7ad3aae6e085 100644 --- a/drivers/firmware/efivars.c +++ b/drivers/firmware/efivars.c @@ -658,13 +658,14 @@ static int efi_pstore_close(struct pstore_info *psi) } 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 @@ static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, 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 ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, 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 @@ static int efi_pstore_write(enum pstore_type_id type, 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 @@ static int efi_pstore_write(enum pstore_type_id type, 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 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, 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 @@ static int efi_pstore_close(struct pstore_info *psi) 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 ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, 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; -- cgit v1.2.3