s390/ctrlchar: improve handling of magic sysrequests

Extract the sysrq handling from the ctrlchar_handle() into a separate
function that can be directly used by other users.

Introduce a new sysrq_work structure to embed the work_struct and to
specify the magic sysrq function to be invoked.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

2 files changed, 23 insertions, 5 deletions

diff --git a/drivers/s390/char/ctrlchar.c b/drivers/s390/char/ctrlchar.c
index 8de2deb176d7..f7d92584b993 100644
--- a/drivers/s390/char/ctrlchar.c
+++ b/drivers/s390/char/ctrlchar.c
@@ -14,15 +14,21 @@
 #include "ctrlchar.h"
 
 #ifdef CONFIG_MAGIC_SYSRQ
-static int ctrlchar_sysrq_key;
+static struct sysrq_work ctrlchar_sysrq;
 
 static void
 ctrlchar_handle_sysrq(struct work_struct *work)
 {
-        handle_sysrq(ctrlchar_sysrq_key);
+        struct sysrq_work *sysrq = container_of(work, struct sysrq_work, work);
+
+        handle_sysrq(sysrq->key);
 }
 
-static DECLARE_WORK(ctrlchar_work, ctrlchar_handle_sysrq);
+void schedule_sysrq_work(struct sysrq_work *sw)
+{
+        INIT_WORK(&sw->work, ctrlchar_handle_sysrq);
+        schedule_work(&sw->work);
+}
 #endif
 
 
@@ -51,8 +57,8 @@ ctrlchar_handle(const unsigned char *buf, int len, struct tty_struct *tty)
 #ifdef CONFIG_MAGIC_SYSRQ
         /* racy */
         if (len == 3 && buf[1] == '-') {
-                ctrlchar_sysrq_key = buf[2];
-                schedule_work(&ctrlchar_work);
+                ctrlchar_sysrq.key = buf[2];
+                schedule_sysrq_work(&ctrlchar_sysrq);
                 return CTRLCHAR_SYSRQ;
         }
 #endif
diff --git a/drivers/s390/char/ctrlchar.h b/drivers/s390/char/ctrlchar.h
index 1a53552f4981..59c2d6e55e55 100644
--- a/drivers/s390/char/ctrlchar.h
+++ b/drivers/s390/char/ctrlchar.h
@@ -7,6 +7,8 @@
  */
 
 #include <linux/tty.h>
+#include <linux/sysrq.h>
+#include <linux/workqueue.h>
 
 extern unsigned int
 ctrlchar_handle(const unsigned char *buf, int len, struct tty_struct *tty);
@@ -17,3 +19,13 @@ ctrlchar_handle(const unsigned char *buf, int len, struct tty_struct *tty);
 #define CTRLCHAR_SYSRQ (3 << 8)
 
 #define CTRLCHAR_MASK (~0xffu)
+
+
+#ifdef CONFIG_MAGIC_SYSRQ
+struct sysrq_work {
+        int key;
+        struct work_struct work;
+};
+
+void schedule_sysrq_work(struct sysrq_work *sw);
+#endif