s390/3270: fix lockdep false positive on view->lock

[ Upstream commit 5712f3301a12c0c3de9cc423484496b0464f2faf ]

The spinlock in the raw3270_view structure is used by con3270, tty3270
and fs3270 in different ways. For con3270 the lock can be acquired in
irq context, for tty3270 and fs3270 the highest context is bh.

Lockdep sees the view->lock as a single class and if the 3270 driver
is used for the console the following message is generated:

WARNING: inconsistent lock state
5.1.0-rc3-05157-g5c168033979d #12 Not tainted
--------------------------------
inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
swapper/0/1 [HC0[0]:SC1[1]:HE1:SE0] takes:
(____ptrval____) (&(&view->lock)->rlock){?.-.}, at: tty3270_update+0x7c/0x330

Introduce a lockdep subclass for the view lock to distinguish bh from
irq locks.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/s390/char/con3270.c b/drivers/s390/char/con3270.c
index 285b4006f44bb9384b15edb2213e368123c90c94..5d5e78afde88a249250d488c20b00e0746022e43 100644 (file)
--- a/drivers/s390/char/con3270.c
+++ b/drivers/s390/char/con3270.c
@@ -628,7 +628,7 @@ con3270_init(void)
                     (void (*)(unsigned long)) con3270_read_tasklet,
                     (unsigned long) condev->read);
 
-       raw3270_add_view(&condev->view, &con3270_fn, 1);
+       raw3270_add_view(&condev->view, &con3270_fn, 1, RAW3270_VIEW_LOCK_IRQ);
 
        INIT_LIST_HEAD(&condev->freemem);
        for (i = 0; i < CON3270_STRING_PAGES; i++) {

diff --git a/drivers/s390/char/fs3270.c b/drivers/s390/char/fs3270.c
index 85eca1cef06305e60c29b99a09ffdce59258c5df..04a6810a4298ce418c29dd567438bff1bb2027d8 100644 (file)
--- a/drivers/s390/char/fs3270.c
+++ b/drivers/s390/char/fs3270.c
@@ -462,7 +462,8 @@ fs3270_open(struct inode *inode, struct file *filp)
 
        init_waitqueue_head(&fp->wait);
        fp->fs_pid = get_pid(task_pid(current));
-       rc = raw3270_add_view(&fp->view, &fs3270_fn, minor);
+       rc = raw3270_add_view(&fp->view, &fs3270_fn, minor,
+                             RAW3270_VIEW_LOCK_BH);
        if (rc) {
                fs3270_free_view(&fp->view);
                goto out;

diff --git a/drivers/s390/char/raw3270.c b/drivers/s390/char/raw3270.c
index a2da898ce90fd942ef272202ebc407eedbe40d10..1ebf632e327b973fbba86fe0dbfa9428af289e9f 100644 (file)
--- a/drivers/s390/char/raw3270.c
+++ b/drivers/s390/char/raw3270.c
@@ -919,7 +919,7 @@ raw3270_deactivate_view(struct raw3270_view *view)
  * Add view to device with minor "minor".
  */
 int
-raw3270_add_view(struct raw3270_view *view, struct raw3270_fn *fn, int minor)
+raw3270_add_view(struct raw3270_view *view, struct raw3270_fn *fn, int minor, int subclass)
 {
        unsigned long flags;
        struct raw3270 *rp;
@@ -941,6 +941,7 @@ raw3270_add_view(struct raw3270_view *view, struct raw3270_fn *fn, int minor)
                view->cols = rp->cols;
                view->ascebc = rp->ascebc;
                spin_lock_init(&view->lock);
+               lockdep_set_subclass(&view->lock, subclass);
                list_add(&view->list, &rp->view_list);
                rc = 0;
                spin_unlock_irqrestore(get_ccwdev_lock(rp->cdev), flags);

diff --git a/drivers/s390/char/raw3270.h b/drivers/s390/char/raw3270.h
index 56519cbb165c7db9da236b4246a4fba011d8df4b..7577d7d0ad48688b8c8ad0ad069af24b5656aebf 100644 (file)
--- a/drivers/s390/char/raw3270.h
+++ b/drivers/s390/char/raw3270.h
@@ -149,6 +149,8 @@ struct raw3270_fn {
 struct raw3270_view {
        struct list_head list;
        spinlock_t lock;
+#define RAW3270_VIEW_LOCK_IRQ  0
+#define RAW3270_VIEW_LOCK_BH   1
        atomic_t ref_count;
        struct raw3270 *dev;
        struct raw3270_fn *fn;
@@ -157,7 +159,7 @@ struct raw3270_view {
        unsigned char *ascebc;          /* ascii -> ebcdic table */
 };
 
-int raw3270_add_view(struct raw3270_view *, struct raw3270_fn *, int);
+int raw3270_add_view(struct raw3270_view *, struct raw3270_fn *, int, int);
 int raw3270_activate_view(struct raw3270_view *);
 void raw3270_del_view(struct raw3270_view *);
 void raw3270_deactivate_view(struct raw3270_view *);

diff --git a/drivers/s390/char/tty3270.c b/drivers/s390/char/tty3270.c
index 272cb6cd1b2ac34afc9b9f38e7fe71f3c0b3f18d..6dd6f9ff7de56d9488e804d386d53c32534d0e8b 100644 (file)
--- a/drivers/s390/char/tty3270.c
+++ b/drivers/s390/char/tty3270.c
@@ -978,7 +978,8 @@ static int tty3270_install(struct tty_driver *driver, struct tty_struct *tty)
                return PTR_ERR(tp);
 
        rc = raw3270_add_view(&tp->view, &tty3270_fn,
-                             tty->index + RAW3270_FIRSTMINOR);
+                             tty->index + RAW3270_FIRSTMINOR,
+                             RAW3270_VIEW_LOCK_BH);
        if (rc) {
                tty3270_free_view(tp);
                return rc;