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| author | Rafael J. Wysocki <rjw@sisk.pl> | 2012-02-29 12:22:41 +0530 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-03-04 09:49:23 -0800 |
| commit | 4e5c29cfbc26e6ebb93c54d1652f41d90d6a8843 (patch) | |
| tree | 0fec7041cd7b0251f17c27881c09c5a0129d36b8 | |
| parent | 7fce3f2db5913f1fe1fbd4fddd4d3af274098006 (diff) | |
| download | lwn-4e5c29cfbc26e6ebb93c54d1652f41d90d6a8843.tar.gz lwn-4e5c29cfbc26e6ebb93c54d1652f41d90d6a8843.zip | |
PM: Print a warning if firmware is requested when tasks are frozen
[ 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>
| -rw-r--r-- | drivers/base/firmware_class.c | 5 | ||||
| -rw-r--r-- | include/linux/kmod.h | 5 | ||||
| -rw-r--r-- | kernel/kmod.c | 9 |
3 files changed, 19 insertions, 0 deletions
diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c index f6872f99491e..fdae756c1494 100644 --- a/drivers/base/firmware_class.c +++ b/drivers/base/firmware_class.c @@ -489,6 +489,11 @@ _request_firmware(const struct firmware **firmware_p, const char *name, 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 384ca8bbf1ac..5a048bdcc1d2 100644 --- 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__ */ diff --git a/kernel/kmod.c b/kernel/kmod.c index d20607840872..163a9193f5c3 100644 --- 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); |