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

1 files changed, 2 insertions, 3 deletions

diff --git a/include/linux/kmod.h b/include/linux/kmod.h
index 9efeae679106..97d22c3e08b1 100644
--- a/include/linux/kmod.h
+++ b/include/linux/kmod.h
@@ -114,8 +114,7 @@ extern void usermodehelper_init(void);
 
 extern int usermodehelper_disable(void);
 extern void usermodehelper_enable(void);
-extern bool usermodehelper_is_disabled(void);
-extern void read_lock_usermodehelper(void);
-extern void read_unlock_usermodehelper(void);
+extern int usermodehelper_read_trylock(void);
+extern void usermodehelper_read_unlock(void);
 
 #endif /* __LINUX_KMOD_H__ */