orderly_poweroff() can be used from any context but UMH_WAIT_EXEC
is sleepable. Move the "force" logic into __orderly_poweroff() and
change orderly_poweroff() to use the global poweroff_work which
simply calls __orderly_poweroff().
While at it, remove the unneeded "int argc" and change argv_split()
to use GFP_KERNEL.
We use the global "bool poweroff_force" to pass the argument, this
can obviously affect the previous request if it is pending/running.
So we only allow the "false => true" transition assuming that the
pending "true" should succeed anyway. If schedule_work() fails after
that we know that work->func() was not called yet, it must see the
new value.
This means that orderly_poweroff() becomes async even if we do not
run the command and always succeeds, schedule_work() can only fail
if the work is already pending. We can export __orderly_poweroff()
and change the non-atomic callers which want the old semantics.
Reported-by: Benjamin Herrenschmidt <b...@kernel.crashing.org>
Signed-off-by: Oleg Nesterov <o...@redhat.com>
---
kernel/sys.c | 57 ++++++++++++++++++++++++++++++++-------------------------
1 files changed, 32 insertions(+), 25 deletions(-)
diff --git a/kernel/sys.c b/kernel/sys.c
index e02a036..7c9565f 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -2184,9 +2184,8 @@ SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned
__user *, nodep,
char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
-static int __orderly_poweroff(void)
+static int __orderly_poweroff(bool force)
{
- int argc;
char **argv;
static char *envp[] = {
"HOME=/",
@@ -2195,20 +2194,40 @@ static int __orderly_poweroff(void)
};
int ret;
- argv = argv_split(GFP_ATOMIC, poweroff_cmd, &argc);
- if (argv == NULL) {
+ argv = argv_split(GFP_KERNEL, poweroff_cmd, NULL);
+ if (argv) {
+ ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
+ argv_free(argv);
+ } else {
printk(KERN_WARNING "%s failed to allocate memory for \"%s\"\n",
- __func__, poweroff_cmd);
- return -ENOMEM;
+ __func__, poweroff_cmd);
+ ret = -ENOMEM;
}
- ret = call_usermodehelper_fns(argv[0], argv, envp, UMH_WAIT_EXEC,
- NULL, NULL, NULL);
- argv_free(argv);
+ if (ret && force) {
+ printk(KERN_WARNING "Failed to start orderly shutdown: "
+ "forcing the issue\n");
+ /*
+ * I guess this should try to kick off some daemon to sync and
+ * poweroff asap. Or not even bother syncing if we're doing an
+ * emergency shutdown?
+ */
+ emergency_sync();
+ kernel_power_off();
+ }
return ret;
}
+static bool poweroff_force;
+
+static void poweroff_work_func(struct work_struct *work)
+{
+ __orderly_poweroff(poweroff_force);
+}
+
+static DECLARE_WORK(poweroff_work, poweroff_work_func);
+
/**
* orderly_poweroff - Trigger an orderly system poweroff
* @force: force poweroff if command execution fails
@@ -2218,21 +2237,9 @@ static int __orderly_poweroff(void)
*/
int orderly_poweroff(bool force)
{
- int ret = __orderly_poweroff();
-
- if (ret && force) {
- printk(KERN_WARNING "Failed to start orderly shutdown: "
- "forcing the issue\n");
-
- /*
- * I guess this should try to kick off some daemon to sync and
- * poweroff asap. Or not even bother syncing if we're doing an
- * emergency shutdown?
- */
- emergency_sync();
- kernel_power_off();
- }
-
- return ret;
+ if (force) /* do not override the pending "true" */
+ poweroff_force = true;
+ schedule_work(&poweroff_work);
+ return 0;
}
EXPORT_SYMBOL_GPL(orderly_poweroff);
--
1.5.5.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
