firmware_class: Do not warn that system is not ready from async loads

If firmware is requested asynchronously, by calling
request_firmware_nowait(), there is no reason to fail the request
(and warn the user) when the system is (presumably temporarily)
unready to handle it (because user space is not available yet or
frozen).  For this reason, introduce an alternative routine for
read-locking umhelper_sem, usermodehelper_read_lock_wait(), that
will wait for usermodehelper_disabled to be unset (possibly with
a timeout) and make request_firmware_work_func() use it instead of
usermodehelper_read_trylock().

Accordingly, modify request_firmware() so that it uses
usermodehelper_read_trylock() to acquire umhelper_sem and remove
the code related to that lock from _request_firmware().

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, 1 insertions, 0 deletions

diff --git a/include/linux/kmod.h b/include/linux/kmod.h
index 97d22c3e08b1..b087377ae2c4 100644
--- a/include/linux/kmod.h
+++ b/include/linux/kmod.h
@@ -115,6 +115,7 @@ extern void usermodehelper_init(void);
 extern int usermodehelper_disable(void);
 extern void usermodehelper_enable(void);
 extern int usermodehelper_read_trylock(void);
+extern long usermodehelper_read_lock_wait(long timeout);
 extern void usermodehelper_read_unlock(void);
 
 #endif /* __LINUX_KMOD_H__ */