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authorRafael J. Wysocki <rjw@sisk.pl>2011-05-06 20:09:42 +0200
committerRafael J. Wysocki <rjw@sisk.pl>2011-05-17 23:19:17 +0200
commita144c6a6c924aa1da04dd77fb84b89927354fdff (patch)
tree10cab9080a722a191086f58b9f304329e8a8b942
parente1866b33b1e89f077b7132daae3dfd9a594e9a1a (diff)
PM: Print a warning if firmware is requested when tasks are frozen
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>
-rw-r--r--drivers/base/firmware_class.c5
-rw-r--r--include/linux/kmod.h5
-rw-r--r--kernel/kmod.c9
3 files changed, 19 insertions, 0 deletions
diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index 8c798ef7f13..bbb03e6f725 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -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",
diff --git a/include/linux/kmod.h b/include/linux/kmod.h
index 6efd7a78de6..7f3dbcb7811 100644
--- a/include/linux/kmod.h
+++ b/include/linux/kmod.h
@@ -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__ */
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 9cd0591c96a..9ab513bd0c3 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -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);