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authorRafael J. Wysocki <rjw@sisk.pl>2012-03-28 23:29:45 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-04-13 09:13:53 -0700
commit1cbfac52d7ccb45e3a3ea1941ed626997143456c (patch)
tree6d8fdadcc08a4869815c3024e63be7a704ea74eb /kernel
parentbff4969b619c9a78356eaad56a3d6f4d1ea3a87f (diff)
downloadlwn-1cbfac52d7ccb45e3a3ea1941ed626997143456c.tar.gz
lwn-1cbfac52d7ccb45e3a3ea1941ed626997143456c.zip
firmware_class: Rework usermodehelper check
commit fe2e39d8782d885755139304d8dba0b3e5bfa878 upstream. Instead of two functions, read_lock_usermodehelper() and usermodehelper_is_disabled(), used in combination, introduce usermodehelper_read_trylock() that will only return with umhelper_sem held if usermodehelper_disabled is unset (and will return -EAGAIN otherwise) and make _request_firmware() use it. Rename read_unlock_usermodehelper() to usermodehelper_read_unlock() to follow the naming convention of the new function. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kmod.c24
1 files changed, 11 insertions, 13 deletions
diff --git a/kernel/kmod.c b/kernel/kmod.c
index a0a88543934e..3973cde0cabf 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -296,17 +296,24 @@ static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq);
*/
#define RUNNING_HELPERS_TIMEOUT (5 * HZ)
-void read_lock_usermodehelper(void)
+int usermodehelper_read_trylock(void)
{
+ int ret = 0;
+
down_read(&umhelper_sem);
+ if (usermodehelper_disabled) {
+ up_read(&umhelper_sem);
+ ret = -EAGAIN;
+ }
+ return ret;
}
-EXPORT_SYMBOL_GPL(read_lock_usermodehelper);
+EXPORT_SYMBOL_GPL(usermodehelper_read_trylock);
-void read_unlock_usermodehelper(void)
+void usermodehelper_read_unlock(void)
{
up_read(&umhelper_sem);
}
-EXPORT_SYMBOL_GPL(read_unlock_usermodehelper);
+EXPORT_SYMBOL_GPL(usermodehelper_read_unlock);
/**
* usermodehelper_disable - prevent new helpers from being started
@@ -347,15 +354,6 @@ void usermodehelper_enable(void)
up_write(&umhelper_sem);
}
-/**
- * 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);