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Diffstat (limited to 'drivers/s390/char/tape_34xx.c')
-rw-r--r--drivers/s390/char/tape_34xx.c59
1 files changed, 41 insertions, 18 deletions
diff --git a/drivers/s390/char/tape_34xx.c b/drivers/s390/char/tape_34xx.c
index c17f35b6136a..c26511171ffe 100644
--- a/drivers/s390/char/tape_34xx.c
+++ b/drivers/s390/char/tape_34xx.c
@@ -53,23 +53,11 @@ static void tape_34xx_delete_sbid_from(struct tape_device *, int);
* Medium sense for 34xx tapes. There is no 'real' medium sense call.
* So we just do a normal sense.
*/
-static int
-tape_34xx_medium_sense(struct tape_device *device)
+static void __tape_34xx_medium_sense(struct tape_request *request)
{
- struct tape_request *request;
- unsigned char *sense;
- int rc;
-
- request = tape_alloc_request(1, 32);
- if (IS_ERR(request)) {
- DBF_EXCEPTION(6, "MSEN fail\n");
- return PTR_ERR(request);
- }
-
- request->op = TO_MSEN;
- tape_ccw_end(request->cpaddr, SENSE, 32, request->cpdata);
+ struct tape_device *device = request->device;
+ unsigned char *sense;
- rc = tape_do_io_interruptible(device, request);
if (request->rc == 0) {
sense = request->cpdata;
@@ -88,15 +76,47 @@ tape_34xx_medium_sense(struct tape_device *device)
device->tape_generic_status |= GMT_WR_PROT(~0);
else
device->tape_generic_status &= ~GMT_WR_PROT(~0);
- } else {
+ } else
DBF_EVENT(4, "tape_34xx: medium sense failed with rc=%d\n",
request->rc);
- }
tape_free_request(request);
+}
+
+static int tape_34xx_medium_sense(struct tape_device *device)
+{
+ struct tape_request *request;
+ int rc;
+
+ request = tape_alloc_request(1, 32);
+ if (IS_ERR(request)) {
+ DBF_EXCEPTION(6, "MSEN fail\n");
+ return PTR_ERR(request);
+ }
+ request->op = TO_MSEN;
+ tape_ccw_end(request->cpaddr, SENSE, 32, request->cpdata);
+ rc = tape_do_io_interruptible(device, request);
+ __tape_34xx_medium_sense(request);
return rc;
}
+static void tape_34xx_medium_sense_async(struct tape_device *device)
+{
+ struct tape_request *request;
+
+ request = tape_alloc_request(1, 32);
+ if (IS_ERR(request)) {
+ DBF_EXCEPTION(6, "MSEN fail\n");
+ return;
+ }
+
+ request->op = TO_MSEN;
+ tape_ccw_end(request->cpaddr, SENSE, 32, request->cpdata);
+ request->callback = (void *) __tape_34xx_medium_sense;
+ request->callback_data = NULL;
+ tape_do_io_async(device, request);
+}
+
struct tape_34xx_work {
struct tape_device *device;
enum tape_op op;
@@ -109,6 +129,9 @@ struct tape_34xx_work {
* is inserted but cannot call tape_do_io* from an interrupt context.
* Maybe that's useful for other actions we want to start from the
* interrupt handler.
+ * Note: the work handler is called by the system work queue. The tape
+ * commands started by the handler need to be asynchrounous, otherwise
+ * a deadlock can occur e.g. in case of a deferred cc=1 (see __tape_do_irq).
*/
static void
tape_34xx_work_handler(struct work_struct *work)
@@ -119,7 +142,7 @@ tape_34xx_work_handler(struct work_struct *work)
switch(p->op) {
case TO_MSEN:
- tape_34xx_medium_sense(device);
+ tape_34xx_medium_sense_async(device);
break;
default:
DBF_EVENT(3, "T34XX: internal error: unknown work\n");