s390/qdio: fix roll-back after timeout on ESTABLISH ccw

When qdio_establish() times out while waiting for the ESTABLISH ccw to
complete, it calls qdio_shutdown() to roll back all of its previous
actions. But at this point the qdio_irq's state is still
QDIO_IRQ_STATE_INACTIVE, so qdio_shutdown() will exit immediately
without doing any actual work.

Which means that eg. the qdio_irq's thinint-indicator stays registered,
and cdev->handler isn't restored to its old value. And since
commit 954d6235be41 ("s390/qdio: make thinint registration symmetric")
the qdio_irq also stays on the tiq_list, so on the next qdio_establish()
we might get a helpful BUG from the list-debugging code:

...
[ 4633.512591] list_add double add: new=00000000005a4110, prev=00000001b357db78, next=00000000005a4110.
[ 4633.512621] ------------[ cut here ]------------
[ 4633.512623] kernel BUG at lib/list_debug.c:29!
...
[ 4633.512796]  [<00000001b2c6ee9a>] __list_add_valid+0x82/0xa0
[ 4633.512798] ([<00000001b2c6ee96>] __list_add_valid+0x7e/0xa0)
[ 4633.512800]  [<00000001b2fcecce>] qdio_establish_thinint+0x116/0x190
[ 4633.512805]  [<00000001b2fcbe58>] qdio_establish+0x128/0x498
...

Fix this by extracting a goto-chain from the existing error exits in
qdio_establish(), and check the return value of the wait_event_...()
to detect the timeout condition.

Fixes: 779e6e1c724d ("[S390] qdio: new qdio driver.")
Root-caused-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Cc: <stable@vger.kernel.org> # 2.6.27
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index 3052fab00597c7a81d4e417b472175367d276755..32c8c46b19b6a222396e6a7bb06f54457d1059ce 100644 (file)
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -1083,6 +1083,7 @@ int qdio_establish(struct ccw_device *cdev,
 {
        struct qdio_irq *irq_ptr = cdev->private->qdio_data;
        struct subchannel_id schid;
+       long timeout;
        int rc;
 
        ccw_device_get_schid(cdev, &schid);
@@ -1111,11 +1112,8 @@ int qdio_establish(struct ccw_device *cdev,
        qdio_setup_irq(irq_ptr, init_data);
 
        rc = qdio_establish_thinint(irq_ptr);
-       if (rc) {
-               qdio_shutdown_irq(irq_ptr);
-               mutex_unlock(&irq_ptr->setup_mutex);
-               return rc;
-       }
+       if (rc)
+               goto err_thinint;
 
        /* establish q */
        irq_ptr->ccw.cmd_code = irq_ptr->equeue.cmd;
@@ -1131,15 +1129,16 @@ int qdio_establish(struct ccw_device *cdev,
        if (rc) {
                DBF_ERROR("%4x est IO ERR", irq_ptr->schid.sch_no);
                DBF_ERROR("rc:%4x", rc);
-               qdio_shutdown_thinint(irq_ptr);
-               qdio_shutdown_irq(irq_ptr);
-               mutex_unlock(&irq_ptr->setup_mutex);
-               return rc;
+               goto err_ccw_start;
        }
 
-       wait_event_interruptible_timeout(cdev->private->wait_q,
-               irq_ptr->state == QDIO_IRQ_STATE_ESTABLISHED ||
-               irq_ptr->state == QDIO_IRQ_STATE_ERR, HZ);
+       timeout = wait_event_interruptible_timeout(cdev->private->wait_q,
+                                                  irq_ptr->state == QDIO_IRQ_STATE_ESTABLISHED ||
+                                                  irq_ptr->state == QDIO_IRQ_STATE_ERR, HZ);
+       if (timeout <= 0) {
+               rc = (timeout == -ERESTARTSYS) ? -EINTR : -ETIME;
+               goto err_ccw_timeout;
+       }
 
        if (irq_ptr->state != QDIO_IRQ_STATE_ESTABLISHED) {
                mutex_unlock(&irq_ptr->setup_mutex);
@@ -1156,6 +1155,14 @@ int qdio_establish(struct ccw_device *cdev,
        qdio_print_subchannel_info(irq_ptr);
        qdio_setup_debug_entries(irq_ptr);
        return 0;
+
+err_ccw_timeout:
+err_ccw_start:
+       qdio_shutdown_thinint(irq_ptr);
+err_thinint:
+       qdio_shutdown_irq(irq_ptr);
+       mutex_unlock(&irq_ptr->setup_mutex);
+       return rc;
 }
 EXPORT_SYMBOL_GPL(qdio_establish);