usermodehelper: Tidy up waiting

Rather than using a tri-state integer for the wait flag in
call_usermodehelper_exec, define a proper enum, and use that.  I've
preserved the integer values so that any callers I've missed should
still work OK.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Andi Kleen <ak@suse.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: David Howells <dhowells@redhat.com>

3 files changed, 18 insertions, 13 deletions

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index b4796d850140..57e6448b171e 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -516,7 +516,7 @@ static void cpuset_release_agent(const char *pathbuf)
         envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
         envp[i] = NULL;
 
-        call_usermodehelper(argv[0], argv, envp, 0);
+        call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
         kfree(pathbuf);
 }
 
diff --git a/kernel/kmod.c b/kernel/kmod.c
index d2dce71115d8..78d365c524ed 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -119,7 +119,7 @@ struct subprocess_info {
         char **argv;
         char **envp;
         struct key *ring;
-        int wait;
+        enum umh_wait wait;
         int retval;
         struct file *stdin;
         void (*cleanup)(char **argv, char **envp);
@@ -225,7 +225,7 @@ static int wait_for_helper(void *data)
                         sub_info->retval = ret;
         }
 
-        if (sub_info->wait < 0)
+        if (sub_info->wait == UMH_NO_WAIT)
                 call_usermodehelper_freeinfo(sub_info);
         else
                 complete(sub_info->complete);
@@ -238,26 +238,31 @@ static void __call_usermodehelper(struct work_struct *work)
         struct subprocess_info *sub_info =
                 container_of(work, struct subprocess_info, work);
         pid_t pid;
-        int wait = sub_info->wait;
+        enum umh_wait wait = sub_info->wait;
 
         /* CLONE_VFORK: wait until the usermode helper has execve'd
          * successfully We need the data structures to stay around
          * until that is done.  */
-        if (wait)
+        if (wait == UMH_WAIT_PROC || wait == UMH_NO_WAIT)
                 pid = kernel_thread(wait_for_helper, sub_info,
                                     CLONE_FS | CLONE_FILES | SIGCHLD);
         else
                 pid = kernel_thread(____call_usermodehelper, sub_info,
                                     CLONE_VFORK | SIGCHLD);
 
-        if (wait < 0)
-                return;
+        switch (wait) {
+        case UMH_NO_WAIT:
+                break;
 
-        if (pid < 0) {
+        case UMH_WAIT_PROC:
+                if (pid > 0)
+                        break;
                 sub_info->retval = pid;
+                /* FALLTHROUGH */
+
+        case UMH_WAIT_EXEC:
                 complete(sub_info->complete);
-        } else if (!wait)
-                complete(sub_info->complete);
+        }
 }
 
 /**
@@ -359,7 +364,7 @@ EXPORT_SYMBOL(call_usermodehelper_stdinpipe);
  * (ie. it runs with full root capabilities).
  */
 int call_usermodehelper_exec(struct subprocess_info *sub_info,
-                             int wait)
+                             enum umh_wait wait)
 {
         DECLARE_COMPLETION_ONSTACK(done);
         int retval;
@@ -378,7 +383,7 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info,
         sub_info->wait = wait;
 
         queue_work(khelper_wq, &sub_info->work);
-        if (wait < 0) /* task has freed sub_info */
+        if (wait == UMH_NO_WAIT) /* task has freed sub_info */
                 return 0;
         wait_for_completion(&done);
         retval = sub_info->retval;
diff --git a/kernel/sys.c b/kernel/sys.c
index aeded9ad66ce..18987c7f6add 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -2327,7 +2327,7 @@ int orderly_poweroff(bool force)
 
         call_usermodehelper_setcleanup(info, argv_cleanup);
 
-        ret = call_usermodehelper_exec(info, -1);
+        ret = call_usermodehelper_exec(info, UMH_NO_WAIT);
 
   out:
         if (ret && force) {