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>

14 files changed, 40 insertions, 26 deletions

diff --git a/arch/i386/mach-voyager/voyager_thread.c b/arch/i386/mach-voyager/voyager_thread.c
index b4b24e0e45e1..f9d595338159 100644
--- a/arch/i386/mach-voyager/voyager_thread.c
+++ b/arch/i386/mach-voyager/voyager_thread.c
@@ -52,7 +52,7 @@ execute(const char *string)
                 NULL,
         };
 
-        if ((ret = call_usermodehelper(argv[0], argv, envp, 1)) != 0) {
+        if ((ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC)) != 0) {
                 printk(KERN_ERR "Voyager failed to run \"%s\": %i\n",
                        string, ret);
         }
diff --git a/arch/x86_64/kernel/mce.c b/arch/x86_64/kernel/mce.c
index aa1d15991794..f3fb8174559e 100644
--- a/arch/x86_64/kernel/mce.c
+++ b/arch/x86_64/kernel/mce.c
@@ -174,7 +174,7 @@ static void do_mce_trigger(void)
         if (events != atomic_read(&mce_logged) && trigger[0]) {
                 /* Small race window, but should be harmless.  */
                 atomic_set(&mce_logged, events);
-                call_usermodehelper(trigger, trigger_argv, NULL, -1);
+                call_usermodehelper(trigger, trigger_argv, NULL, UMH_NO_WAIT);
         }
 }
 
diff --git a/drivers/macintosh/therm_pm72.c b/drivers/macintosh/therm_pm72.c
index dbb22403979f..3d90fc002097 100644
--- a/drivers/macintosh/therm_pm72.c
+++ b/drivers/macintosh/therm_pm72.c
@@ -1770,7 +1770,8 @@ static int call_critical_overtemp(void)
                                 "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
                                 NULL };
 
-        return call_usermodehelper(critical_overtemp_path, argv, envp, 0);
+        return call_usermodehelper(critical_overtemp_path,
+                                   argv, envp, UMH_WAIT_EXEC);
 }
 
 
diff --git a/drivers/macintosh/windfarm_core.c b/drivers/macintosh/windfarm_core.c
index e18d265d5d33..516d943227e2 100644
--- a/drivers/macintosh/windfarm_core.c
+++ b/drivers/macintosh/windfarm_core.c
@@ -80,7 +80,8 @@ int wf_critical_overtemp(void)
                                 "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
                                 NULL };
 
-        return call_usermodehelper(critical_overtemp_path, argv, envp, 0);
+        return call_usermodehelper(critical_overtemp_path,
+                                   argv, envp, UMH_WAIT_EXEC);
 }
 EXPORT_SYMBOL_GPL(wf_critical_overtemp);
 
diff --git a/drivers/net/hamradio/baycom_epp.c b/drivers/net/hamradio/baycom_epp.c
index 84aa2117c0ee..355c6cf3d112 100644
--- a/drivers/net/hamradio/baycom_epp.c
+++ b/drivers/net/hamradio/baycom_epp.c
@@ -320,7 +320,7 @@ static int eppconfig(struct baycom_state *bc)
         sprintf(portarg, "%ld", bc->pdev->port->base);
         printk(KERN_DEBUG "%s: %s -s -p %s -m %s\n", bc_drvname, eppconfig_path, portarg, modearg);
 
-        return call_usermodehelper(eppconfig_path, argv, envp, 1);
+        return call_usermodehelper(eppconfig_path, argv, envp, UMH_WAIT_PROC);
 }
 
 /* ---------------------------------------------------------------------- */
diff --git a/drivers/pnp/pnpbios/core.c b/drivers/pnp/pnpbios/core.c
index 03baf1c64a2e..ed112ee16012 100644
--- a/drivers/pnp/pnpbios/core.c
+++ b/drivers/pnp/pnpbios/core.c
@@ -147,7 +147,7 @@ static int pnp_dock_event(int dock, struct pnp_docking_station_info *info)
                 info->location_id, info->serial, info->capabilities);
         envp[i] = NULL;
         
-        value = call_usermodehelper (argv [0], argv, envp, 0);
+        value = call_usermodehelper (argv [0], argv, envp, UMH_WAIT_EXEC);
         kfree (buf);
         kfree (envp);
         return 0;
diff --git a/fs/ocfs2/heartbeat.c b/fs/ocfs2/heartbeat.c
index 352eb4a13f98..c4c36171240d 100644
--- a/fs/ocfs2/heartbeat.c
+++ b/fs/ocfs2/heartbeat.c
@@ -209,7 +209,7 @@ void ocfs2_stop_heartbeat(struct ocfs2_super *osb)
         envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
         envp[2] = NULL;
 
-        ret = call_usermodehelper(argv[0], argv, envp, 1);
+        ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
         if (ret < 0)
                 mlog_errno(ret);
 }
diff --git a/include/linux/kmod.h b/include/linux/kmod.h
index c4cbe59d9c67..5dc13848891b 100644
--- a/include/linux/kmod.h
+++ b/include/linux/kmod.h
@@ -51,15 +51,21 @@ int call_usermodehelper_stdinpipe(struct subprocess_info *sub_info,
 void call_usermodehelper_setcleanup(struct subprocess_info *info,
                                     void (*cleanup)(char **argv, char **envp));
 
+enum umh_wait {
+        UMH_NO_WAIT = -1,       /* don't wait at all */
+        UMH_WAIT_EXEC = 0,      /* wait for the exec, but not the process */
+        UMH_WAIT_PROC = 1,      /* wait for the process to complete */
+};
+
 /* Actually execute the sub-process */
-int call_usermodehelper_exec(struct subprocess_info *info, int wait);
+int call_usermodehelper_exec(struct subprocess_info *info, enum umh_wait wait);
 
 /* Free the subprocess_info. This is only needed if you're not going
    to call call_usermodehelper_exec */
 void call_usermodehelper_freeinfo(struct subprocess_info *info);
 
 static inline int
-call_usermodehelper(char *path, char **argv, char **envp, int wait)
+call_usermodehelper(char *path, char **argv, char **envp, enum umh_wait wait)
 {
         struct subprocess_info *info;
 
@@ -71,7 +77,7 @@ call_usermodehelper(char *path, char **argv, char **envp, int wait)
 
 static inline int
 call_usermodehelper_keys(char *path, char **argv, char **envp,
-                         struct key *session_keyring, int wait)
+                         struct key *session_keyring, enum umh_wait wait)
 {
         struct subprocess_info *info;
 
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) {
diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
index 12e311dc664c..bd5ecbbafab1 100644
--- a/lib/kobject_uevent.c
+++ b/lib/kobject_uevent.c
@@ -208,7 +208,7 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
                 argv [0] = uevent_helper;
                 argv [1] = (char *)subsystem;
                 argv [2] = NULL;
-                call_usermodehelper (argv[0], argv, envp, 0);
+                call_usermodehelper (argv[0], argv, envp, UMH_WAIT_EXEC);
         }
 
 exit:
diff --git a/net/bridge/br_stp_if.c b/net/bridge/br_stp_if.c
index a786e7863200..1ea2f86f7683 100644
--- a/net/bridge/br_stp_if.c
+++ b/net/bridge/br_stp_if.c
@@ -125,7 +125,7 @@ static void br_stp_start(struct net_bridge *br)
         char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL };
         char *envp[] = { NULL };
 
-        r = call_usermodehelper(BR_STP_PROG, argv, envp, 1);
+        r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
         if (r == 0) {
                 br->stp_enabled = BR_USER_STP;
                 printk(KERN_INFO "%s: userspace STP started\n", br->dev->name);
diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index f573ac189a0a..557500110a13 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -108,7 +108,8 @@ static int call_sbin_request_key(struct key *key,
         argv[i] = NULL;
 
         /* do it */
-        ret = call_usermodehelper_keys(argv[0], argv, envp, keyring, 1);
+        ret = call_usermodehelper_keys(argv[0], argv, envp, keyring,
+                                       UMH_WAIT_PROC);
 
 error_link:
         key_put(keyring);