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From srivatsa.bhat@linux.vnet.ibm.com Thu Mar 1 13:30:46 2012
From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Date: Wed, 29 Feb 2012 12:22:41 +0530
Subject: PM: Print a warning if firmware is requested when tasks are frozen
To: gregkh@linuxfoundation.org
Cc: stable@vger.kernel.org, rjw@sisk.pl, valdis.kletnieks@vt.edu, cloos@hjcloos.com, riesebie@lxtec.de, torvalds@linux-foundation.org, penguin-kernel@i-love.sakura.ne.jp, srivatsa.bhat@linux.vnet.ibm.com
Message-ID: <20120229065115.4761.59767.stgit@srivatsabhat.in.ibm.com>
From: Rafael J. Wysocki <rjw@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 <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Reviewed-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@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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