genirq: Adjust irq thread affinity on IRQ_SET_MASK_OK_NOCOPY return value

[linux-flexiantxendom0-3.2.10.git] / kernel / kmod.c

diff --git a/kernel/kmod.c b/kernel/kmod.c
index 2142687..957a7aa 100644 (file)
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -34,6 +34,9 @@
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/resource.h>
+#include <linux/notifier.h>
+#include <linux/suspend.h>
+#include <linux/rwsem.h>
 #include <asm/uaccess.h>
 
 #include <trace/events/module.h>
@@ -48,6 +51,7 @@ static struct workqueue_struct *khelper_wq;
 static kernel_cap_t usermodehelper_bset = CAP_FULL_SET;
 static kernel_cap_t usermodehelper_inheritable = CAP_FULL_SET;
 static DEFINE_SPINLOCK(umh_sysctl_lock);
+static DECLARE_RWSEM(umhelper_sem);
 
 #ifdef CONFIG_MODULES
 
@@ -56,6 +60,43 @@ static DEFINE_SPINLOCK(umh_sysctl_lock);
 */
 char modprobe_path[KMOD_PATH_LEN] = "/sbin/modprobe";
 
+static void free_modprobe_argv(struct subprocess_info *info)
+{
+       kfree(info->argv[3]); /* check call_modprobe() */
+       kfree(info->argv);
+}
+
+static int call_modprobe(char *module_name, int wait)
+{
+       static char *envp[] = {
+               "HOME=/",
+               "TERM=linux",
+               "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
+               NULL
+       };
+
+       char **argv = kmalloc(sizeof(char *[5]), GFP_KERNEL);
+       if (!argv)
+               goto out;
+
+       module_name = kstrdup(module_name, GFP_KERNEL);
+       if (!module_name)
+               goto free_argv;
+
+       argv[0] = modprobe_path;
+       argv[1] = "-q";
+       argv[2] = "--";
+       argv[3] = module_name;  /* check free_modprobe_argv() */
+       argv[4] = NULL;
+
+       return call_usermodehelper_fns(modprobe_path, argv, envp,
+               wait | UMH_KILLABLE, NULL, free_modprobe_argv, NULL);
+free_argv:
+       kfree(argv);
+out:
+       return -ENOMEM;
+}
+
 /**
  * __request_module - try to load a kernel module
  * @wait: wait (or not) for the operation to complete
@@ -77,11 +118,6 @@ int __request_module(bool wait, const char *fmt, ...)
        char module_name[MODULE_NAME_LEN];
        unsigned int max_modprobes;
        int ret;
-       char *argv[] = { modprobe_path, "-q", "--", module_name, NULL };
-       static char *envp[] = { "HOME=/",
-                               "TERM=linux",
-                               "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
-                               NULL };
        static atomic_t kmod_concurrent = ATOMIC_INIT(0);
 #define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */
        static int kmod_loop_msg;
@@ -124,9 +160,7 @@ int __request_module(bool wait, const char *fmt, ...)
 
        trace_module_request(module_name, wait, _RET_IP_);
 
-       ret = call_usermodehelper_fns(modprobe_path, argv, envp,
-                       wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC,
-                       NULL, NULL, NULL);
+       ret = call_modprobe(module_name, wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC);
 
        atomic_dec(&kmod_concurrent);
        return ret;
@@ -184,7 +218,7 @@ static int ____call_usermodehelper(void *data)
        /* Exec failed? */
 fail:
        sub_info->retval = retval;
-       do_exit(0);
+       return 0;
 }
 
 void call_usermodehelper_freeinfo(struct subprocess_info *info)
@@ -195,6 +229,19 @@ void call_usermodehelper_freeinfo(struct subprocess_info *info)
 }
 EXPORT_SYMBOL(call_usermodehelper_freeinfo);
 
+static void umh_complete(struct subprocess_info *sub_info)
+{
+       struct completion *comp = xchg(&sub_info->complete, NULL);
+       /*
+        * See call_usermodehelper_exec(). If xchg() returns NULL
+        * we own sub_info, the UMH_KILLABLE caller has gone away.
+        */
+       if (comp)
+               complete(comp);
+       else
+               call_usermodehelper_freeinfo(sub_info);
+}
+
 /* Keventd can't block, but this (a child) can. */
 static int wait_for_helper(void *data)
 {
@@ -231,7 +278,7 @@ static int wait_for_helper(void *data)
                        sub_info->retval = ret;
        }
 
-       complete(sub_info->complete);
+       umh_complete(sub_info);
        return 0;
 }
 
@@ -240,7 +287,7 @@ static void __call_usermodehelper(struct work_struct *work)
 {
        struct subprocess_info *sub_info =
                container_of(work, struct subprocess_info, work);
-       enum umh_wait wait = sub_info->wait;
+       int wait = sub_info->wait & ~UMH_KILLABLE;
        pid_t pid;
 
        /* CLONE_VFORK: wait until the usermode helper has execve'd
@@ -265,7 +312,7 @@ static void __call_usermodehelper(struct work_struct *work)
        case UMH_WAIT_EXEC:
                if (pid < 0)
                        sub_info->retval = pid;
-               complete(sub_info->complete);
+               umh_complete(sub_info);
        }
 }
 
@@ -273,6 +320,7 @@ static void __call_usermodehelper(struct work_struct *work)
  * If set, call_usermodehelper_exec() will exit immediately returning -EBUSY
  * (used for preventing user land processes from being created after the user
  * land has been frozen during a system-wide hibernation or suspend operation).
+ * Should always be manipulated under umhelper_sem acquired for write.
  */
 static int usermodehelper_disabled = 1;
 
@@ -291,6 +339,18 @@ static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq);
  */
 #define RUNNING_HELPERS_TIMEOUT        (5 * HZ)
 
+void read_lock_usermodehelper(void)
+{
+       down_read(&umhelper_sem);
+}
+EXPORT_SYMBOL_GPL(read_lock_usermodehelper);
+
+void read_unlock_usermodehelper(void)
+{
+       up_read(&umhelper_sem);
+}
+EXPORT_SYMBOL_GPL(read_unlock_usermodehelper);
+
 /**
  * usermodehelper_disable - prevent new helpers from being started
  */
@@ -298,8 +358,10 @@ int usermodehelper_disable(void)
 {
        long retval;
 
+       down_write(&umhelper_sem);
        usermodehelper_disabled = 1;
-       smp_mb();
+       up_write(&umhelper_sem);
+
        /*
         * From now on call_usermodehelper_exec() won't start any new
         * helpers, so it is sufficient if running_helpers turns out to
@@ -312,7 +374,9 @@ int usermodehelper_disable(void)
        if (retval)
                return 0;
 
+       down_write(&umhelper_sem);
        usermodehelper_disabled = 0;
+       up_write(&umhelper_sem);
        return -EAGAIN;
 }
 
@@ -321,7 +385,9 @@ int usermodehelper_disable(void)
  */
 void usermodehelper_enable(void)
 {
+       down_write(&umhelper_sem);
        usermodehelper_disabled = 0;
+       up_write(&umhelper_sem);
 }
 
 /**
@@ -412,8 +478,7 @@ EXPORT_SYMBOL(call_usermodehelper_setfns);
  * asynchronously if wait is not set, and runs as a child of keventd.
  * (ie. it runs with full root capabilities).
  */
-int call_usermodehelper_exec(struct subprocess_info *sub_info,
-                            enum umh_wait wait)
+int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
 {
        DECLARE_COMPLETION_ONSTACK(done);
        int retval = 0;
@@ -433,9 +498,21 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info,
        queue_work(khelper_wq, &sub_info->work);
        if (wait == UMH_NO_WAIT)        /* task has freed sub_info */
                goto unlock;
+
+       if (wait & UMH_KILLABLE) {
+               retval = wait_for_completion_killable(&done);
+               if (!retval)
+                       goto wait_done;
+
+               /* umh_complete() will see NULL and free sub_info */
+               if (xchg(&sub_info->complete, NULL))
+                       goto unlock;
+               /* fallthrough, umh_complete() was already called */
+       }
+
        wait_for_completion(&done);
+wait_done:
        retval = sub_info->retval;
-
 out:
        call_usermodehelper_freeinfo(sub_info);
 unlock: