PM: Print a warning if firmware is requested when tasks are frozen
authorRafael J. Wysocki <rjw@sisk.pl>
Fri, 6 May 2011 18:09:42 +0000 (20:09 +0200)
committerRafael J. Wysocki <rjw@sisk.pl>
Tue, 17 May 2011 21:19:17 +0000 (23:19 +0200)
Some drivers erroneously use request_firmware() from their ->resume()
(or ->thaw(), or ->restore()) callbacks, which is not going to work
unless the firmware has been built in.  This causes system resume to
stall until the firmware-loading timeout expires, which makes users
think that the resume has failed and reboot their machines
unnecessarily.  For this reason, make _request_firmware() print a
warning and return immediately with error code if it has been called
when tasks are frozen and it's impossible to start any new usermode
helpers.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Reviewed-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
drivers/base/firmware_class.c
include/linux/kmod.h
kernel/kmod.c

index 8c798ef7f13fcc25ea1627ed3870dca0b97d1a21..bbb03e6f7255b715e894080e66a7ccfae34b2c24 100644 (file)
@@ -521,6 +521,11 @@ static int _request_firmware(const struct firmware **firmware_p,
        if (!firmware_p)
                return -EINVAL;
 
+       if (WARN_ON(usermodehelper_is_disabled())) {
+               dev_err(device, "firmware: %s will not be loaded\n", name);
+               return -EBUSY;
+       }
+
        *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
        if (!firmware) {
                dev_err(device, "%s: kmalloc(struct firmware) failed\n",
index 6efd7a78de6aaaa6d74c526ba44f5fafa81e1fad..7f3dbcb78116ae811b5b287bf77a3ad9e18e3abf 100644 (file)
@@ -111,7 +111,12 @@ call_usermodehelper(char *path, char **argv, char **envp, enum umh_wait wait)
 
 extern void usermodehelper_init(void);
 
+#ifdef CONFIG_PM_SLEEP
 extern int usermodehelper_disable(void);
 extern void usermodehelper_enable(void);
+extern bool usermodehelper_is_disabled(void);
+#else
+static inline bool usermodehelper_is_disabled(void) { return false; }
+#endif
 
 #endif /* __LINUX_KMOD_H__ */
index 9cd0591c96a21acf825861c7672533c0273ae25e..9ab513bd0c3c461f9814fcf2d5c1795f8c2227f8 100644 (file)
@@ -301,6 +301,15 @@ void usermodehelper_enable(void)
        usermodehelper_disabled = 0;
 }
 
+/**
+ * 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);