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 be3e3c1206c242bc849b732d1ad09f1e8f9a8afc..1868ff803f439c8faf68af2316ac7a21eeb9a713 100644 (file)
--- a/drivers/s390/char/con3270.c
+++ b/drivers/s390/char/con3270.c
@@ -629,7 +629,7 @@ 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 c4518168fd02c98013b349e17fdba30c8d65eec5..4f73a38c7cbd278ff9cb85d2ca446bc537fdcb62 100644 (file)
--- a/drivers/s390/char/fs3270.c
+++ b/drivers/s390/char/fs3270.c
@@ -463,7 +463,8 @@ 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 5d4f053d7c38c330d969586fa3eae0b40f6955ca..0f47fec35acc0ee1aef2d20e467f8a7dafc84b6d 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 114ca7cbf8897dce734e59cb283923e2c160b3bf..3afaa35f73513cba47566e9601b775339e6cdf78 100644 (file)
--- a/drivers/s390/char/raw3270.h
+++ b/drivers/s390/char/raw3270.h
@@ -150,6 +150,8 @@ 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;
@@ -158,7 +160,7 @@ 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 e5ebe2fbee2353435002ec357542efd336c47f12..401688bf8fd378d35223f21f305c0188aa86b01d 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;