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authorPaul Walmsley <paul@pwsan.com>2012-09-22 10:00:11 -0600
committerPaul Walmsley <paul@pwsan.com>2012-09-22 10:00:11 -0600
commit5dbd6535d5bcb9d1899dd27d209ca651431df66b (patch)
tree137231cd0e8e01a30e4946625836d512db6830e7 /drivers/tty/tty_mutex.c
parent5698bd757d55b1bb87edd1a9744ab09c142abfc2 (diff)
parentde6ca33a96a6bf61fcb91d3d399703e19ead9d1e (diff)
Merge tag 'cleanup-fixes-for-v3.7' into test_v3.6-rc6_cff3.7_odaf3.7
These fixes are needed to fix non-omap build breakage for twl-core driver and to fix omap1_defconfig compile when led driver changes and omap sparse IRQ changes are merged together. Also fix warnings for omaps not using pinctrl framework yet.
Diffstat (limited to 'drivers/tty/tty_mutex.c')
-rw-r--r--drivers/tty/tty_mutex.c71
1 files changed, 56 insertions, 15 deletions
diff --git a/drivers/tty/tty_mutex.c b/drivers/tty/tty_mutex.c
index 9ff986c32a2..67feac9e6eb 100644
--- a/drivers/tty/tty_mutex.c
+++ b/drivers/tty/tty_mutex.c
@@ -4,29 +4,70 @@
#include <linux/semaphore.h>
#include <linux/sched.h>
-/*
- * The 'big tty mutex'
- *
- * This mutex is taken and released by tty_lock() and tty_unlock(),
- * replacing the older big kernel lock.
- * It can no longer be taken recursively, and does not get
- * released implicitly while sleeping.
- *
- * Don't use in new code.
- */
-static DEFINE_MUTEX(big_tty_mutex);
+/* Legacy tty mutex glue */
+
+enum {
+ TTY_MUTEX_NORMAL,
+ TTY_MUTEX_NESTED,
+};
/*
* Getting the big tty mutex.
*/
-void __lockfunc tty_lock(void)
+
+static void __lockfunc tty_lock_nested(struct tty_struct *tty,
+ unsigned int subclass)
{
- mutex_lock(&big_tty_mutex);
+ if (tty->magic != TTY_MAGIC) {
+ printk(KERN_ERR "L Bad %p\n", tty);
+ WARN_ON(1);
+ return;
+ }
+ tty_kref_get(tty);
+ mutex_lock_nested(&tty->legacy_mutex, subclass);
+}
+
+void __lockfunc tty_lock(struct tty_struct *tty)
+{
+ return tty_lock_nested(tty, TTY_MUTEX_NORMAL);
}
EXPORT_SYMBOL(tty_lock);
-void __lockfunc tty_unlock(void)
+void __lockfunc tty_unlock(struct tty_struct *tty)
{
- mutex_unlock(&big_tty_mutex);
+ if (tty->magic != TTY_MAGIC) {
+ printk(KERN_ERR "U Bad %p\n", tty);
+ WARN_ON(1);
+ return;
+ }
+ mutex_unlock(&tty->legacy_mutex);
+ tty_kref_put(tty);
}
EXPORT_SYMBOL(tty_unlock);
+
+/*
+ * Getting the big tty mutex for a pair of ttys with lock ordering
+ * On a non pty/tty pair tty2 can be NULL which is just fine.
+ */
+void __lockfunc tty_lock_pair(struct tty_struct *tty,
+ struct tty_struct *tty2)
+{
+ if (tty < tty2) {
+ tty_lock(tty);
+ tty_lock_nested(tty2, TTY_MUTEX_NESTED);
+ } else {
+ if (tty2 && tty2 != tty)
+ tty_lock(tty2);
+ tty_lock_nested(tty, TTY_MUTEX_NESTED);
+ }
+}
+EXPORT_SYMBOL(tty_lock_pair);
+
+void __lockfunc tty_unlock_pair(struct tty_struct *tty,
+ struct tty_struct *tty2)
+{
+ tty_unlock(tty);
+ if (tty2 && tty2 != tty)
+ tty_unlock(tty2);
+}
+EXPORT_SYMBOL(tty_unlock_pair);