firmware_class: Rework usermodehelper check
Instead of two functions, read_lock_usermodehelper() and
usermodehelper_is_disabled(), used in combination, introduce
usermodehelper_read_trylock() that will only return with umhelper_sem
held if usermodehelper_disabled is unset (and will return -EAGAIN
otherwise) and make _request_firmware() use it.
Rename read_unlock_usermodehelper() to
usermodehelper_read_unlock() to follow the naming convention of the
new function.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 957a7aa..4079ac1 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -339,17 +339,24 @@
*/
#define RUNNING_HELPERS_TIMEOUT (5 * HZ)
-void read_lock_usermodehelper(void)
+int usermodehelper_read_trylock(void)
{
- down_read(&umhelper_sem);
-}
-EXPORT_SYMBOL_GPL(read_lock_usermodehelper);
+ int ret = 0;
-void read_unlock_usermodehelper(void)
+ down_read(&umhelper_sem);
+ if (usermodehelper_disabled) {
+ up_read(&umhelper_sem);
+ ret = -EAGAIN;
+ }
+ return ret;
+}
+EXPORT_SYMBOL_GPL(usermodehelper_read_trylock);
+
+void usermodehelper_read_unlock(void)
{
up_read(&umhelper_sem);
}
-EXPORT_SYMBOL_GPL(read_unlock_usermodehelper);
+EXPORT_SYMBOL_GPL(usermodehelper_read_unlock);
/**
* usermodehelper_disable - prevent new helpers from being started
@@ -390,15 +397,6 @@
up_write(&umhelper_sem);
}
-/**
- * usermodehelper_is_disabled - check if new helpers are allowed to be started
- */
-bool usermodehelper_is_disabled(void)
-{
- return usermodehelper_disabled;
-}
-EXPORT_SYMBOL_GPL(usermodehelper_is_disabled);
-
static void helper_lock(void)
{
atomic_inc(&running_helpers);