[PATCH 3/5] watchdog: diag288_wdt: unify command buffer handling for diag288 zvm

Alexander Egorenkov
2023-02-03T07:40:45Z

Simplify and de-duplicate code by introducing a common single command
buffer allocated once at initialization. Moreover, simplify the interface
of __diag288_vm() by accepting ASCII strings as the command parameter
and converting it to the EBCDIC format within the function itself.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Egorenkov <egorenar@linux.ibm.com>
---
drivers/watchdog/diag288_wdt.c | 55 +++++++++++++---------------------
1 file changed, 20 insertions(+), 35 deletions(-)

diff --git a/drivers/watchdog/diag288_wdt.c b/drivers/watchdog/diag288_wdt.c
index c8d516ced6d2..c717f47dd4c3 100644
--- a/drivers/watchdog/diag288_wdt.c
+++ b/drivers/watchdog/diag288_wdt.c
@@ -69,6 +69,8 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default = C

MODULE_ALIAS("vmwatchdog");

+static char *cmd_buf;
+
static int __diag288(unsigned int func, unsigned int timeout,
unsigned long action, unsigned int len)
{
@@ -88,11 +90,18 @@ static int __diag288(unsigned int func, unsigned int timeout,
return err;
}

-static int __diag288_vm(unsigned int func, unsigned int timeout,
- char *cmd, size_t len)
+static int __diag288_vm(unsigned int func, unsigned int timeout, char *cmd)
{
+ ssize_t len;
+
+ len = strscpy(cmd_buf, cmd, MAX_CMDLEN);
+ if (len < 0)
+ return len;
+ ASCEBC(cmd_buf, MAX_CMDLEN);
+ EBC_TOUPPER(cmd_buf, MAX_CMDLEN);
+
diag_stat_inc(DIAG_STAT_X288);
- return __diag288(func, timeout, virt_to_phys(cmd), len);
+ return __diag288(func, timeout, virt_to_phys(cmd_buf), len);
}

static int __diag288_lpar(unsigned int func, unsigned int timeout,
@@ -104,24 +113,14 @@ static int __diag288_lpar(unsigned int func, unsigned int timeout,

static int wdt_start(struct watchdog_device *dev)
{
- char *ebc_cmd;
- size_t len;
int ret;
unsigned int func;

if (MACHINE_IS_VM) {
- ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
- if (!ebc_cmd)
- return -ENOMEM;
- len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
- ASCEBC(ebc_cmd, MAX_CMDLEN);
- EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
-
func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL)
: WDT_FUNC_INIT;
- ret = __diag288_vm(func, dev->timeout, ebc_cmd, len);
+ ret = __diag288_vm(func, dev->timeout, wdt_cmd);
WARN_ON(ret != 0);
- kfree(ebc_cmd);
} else {
ret = __diag288_lpar(WDT_FUNC_INIT,
dev->timeout, LPARWDT_RESTART);
@@ -146,19 +145,10 @@ static int wdt_stop(struct watchdog_device *dev)

static int wdt_ping(struct watchdog_device *dev)
{
- char *ebc_cmd;
- size_t len;
int ret;
unsigned int func;

if (MACHINE_IS_VM) {
- ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
- if (!ebc_cmd)
- return -ENOMEM;
- len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
- ASCEBC(ebc_cmd, MAX_CMDLEN);
- EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
-
/*
* It seems to be ok to z/VM to use the init function to
* retrigger the watchdog. On LPAR WDT_FUNC_CHANGE must
@@ -167,9 +157,8 @@ static int wdt_ping(struct watchdog_device *dev)
func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL)
: WDT_FUNC_INIT;

- ret = __diag288_vm(func, dev->timeout, ebc_cmd, len);
+ ret = __diag288_vm(func, dev->timeout, wdt_cmd);
WARN_ON(ret != 0);
- kfree(ebc_cmd);
} else {
ret = __diag288_lpar(WDT_FUNC_CHANGE, dev->timeout, 0);
}
@@ -212,25 +201,20 @@ static struct watchdog_device wdt_dev = {
static int __init diag288_init(void)
{
int ret;
- char ebc_begin[] = {
- 194, 197, 199, 201, 213
- };
- char *ebc_cmd;

watchdog_set_nowayout(&wdt_dev, nowayout_info);

if (MACHINE_IS_VM) {
- ebc_cmd = kmalloc(sizeof(ebc_begin), GFP_KERNEL);
- if (!ebc_cmd) {
+ cmd_buf = kmalloc(MAX_CMDLEN, GFP_KERNEL);
+ if (!cmd_buf) {
pr_err("The watchdog cannot be initialized\n");
return -ENOMEM;
}
- memcpy(ebc_cmd, ebc_begin, sizeof(ebc_begin));
- ret = __diag288_vm(WDT_FUNC_INIT, 15,
- ebc_cmd, sizeof(ebc_begin));
- kfree(ebc_cmd);
+
+ ret = __diag288_vm(WDT_FUNC_INIT, MIN_INTERVAL, "BEGIN");
if (ret != 0) {
pr_err("The watchdog cannot be initialized\n");
+ kfree(cmd_buf);
return -EINVAL;
}
} else {
@@ -251,6 +235,7 @@ static int __init diag288_init(void)
static void __exit diag288_exit(void)
{
watchdog_unregister_device(&wdt_dev);
+ kfree(cmd_buf);
}

module_init(diag288_init);
--
2.37.2