2.6.32-longterm review patch. If anyone has any objections, please let me know.
------------------
From: Rafael J. Wysocki <r...@sisk.pl>
[ Upstream commit a144c6a6c924aa1da04dd77fb84b89927354fdff ]
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 <r...@sisk.pl>
Acked-by: Greg Kroah-Hartman <gre...@suse.de>
Reviewed-by: Valdis Kletnieks <valdis.kletni...@vt.edu>
Signed-off-by: Srivatsa S. Bhat <srivatsa.b...@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/base/firmware_class.c | 5 +++++
include/linux/kmod.h | 5 +++++
kernel/kmod.c | 9 +++++++++
3 files changed, 19 insertions(+)
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -489,6 +489,11 @@ _request_firmware(const struct firmware
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",
--- a/include/linux/kmod.h
+++ b/include/linux/kmod.h
@@ -104,7 +104,12 @@ struct file;
extern int call_usermodehelper_pipe(char *path, char *argv[], char *envp[],
struct file **filp);
+#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__ */
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -337,6 +337,15 @@ 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);
--
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