[PATCH 4/9] dasd: Implement block timeout handling

Martin Schwidefsky
2013-06-03T15:05:22Z

This patch implements generic block layer timeout handling
callbacks for DASDs. When the timeout expires the respective
cqr is aborted.

With this timeout handler time-critical request abort
is guaranteed as the abort does not depend on the internal
state of the various DASD driver queues.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Acked-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
drivers/s390/block/dasd.c | 76 ++++++++++++++++++++++++++++++++++++++++
drivers/s390/block/dasd_diag.c | 5 ++-
drivers/s390/block/dasd_eckd.c | 4 +++
drivers/s390/block/dasd_fba.c | 5 ++-
4 files changed, 88 insertions(+), 2 deletions(-)

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 000e514..87478be 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -2573,8 +2573,10 @@ static void __dasd_process_request_queue(struct dasd_block *block)
*/
cqr->callback_data = (void *) req;
cqr->status = DASD_CQR_FILLED;
+ req->completion_data = cqr;
blk_start_request(req);
list_add_tail(&cqr->blocklist, &block->ccw_queue);
+ INIT_LIST_HEAD(&cqr->devlist);
dasd_profile_start(block, cqr, req);
}
}
@@ -2862,6 +2864,80 @@ static void do_dasd_request(struct request_queue *queue)
}

/*
+ * Block timeout callback, called from the block layer
+ *
+ * request_queue lock is held on entry.
+ *
+ * Return values:
+ * BLK_EH_RESET_TIMER if the request should be left running
+ * BLK_EH_NOT_HANDLED if the request is handled or terminated
+ * by the driver.
+ */
+enum blk_eh_timer_return dasd_times_out(struct request *req)
+{
+ struct dasd_ccw_req *cqr = req->completion_data;
+ struct dasd_block *block = req->q->queuedata;
+ struct dasd_device *device;
+ int rc = 0;
+
+ if (!cqr)
+ return BLK_EH_NOT_HANDLED;
+
+ device = cqr->startdev ? cqr->startdev : block->base;
+ DBF_DEV_EVENT(DBF_WARNING, device,
+ " dasd_times_out cqr %p status %x",
+ cqr, cqr->status);
+
+ spin_lock(&block->queue_lock);
+ spin_lock(get_ccwdev_lock(device->cdev));
+ cqr->retries = -1;
+ cqr->intrc = -ETIMEDOUT;
+ if (cqr->status >= DASD_CQR_QUEUED) {
+ spin_unlock(get_ccwdev_lock(device->cdev));
+ rc = dasd_cancel_req(cqr);
+ } else if (cqr->status == DASD_CQR_FILLED ||
+ cqr->status == DASD_CQR_NEED_ERP) {
+ cqr->status = DASD_CQR_TERMINATED;
+ spin_unlock(get_ccwdev_lock(device->cdev));
+ } else if (cqr->status == DASD_CQR_IN_ERP) {
+ struct dasd_ccw_req *searchcqr, *nextcqr, *tmpcqr;
+
+ list_for_each_entry_safe(searchcqr, nextcqr,
+ &block->ccw_queue, blocklist) {
+ tmpcqr = searchcqr;
+ while (tmpcqr->refers)
+ tmpcqr = tmpcqr->refers;
+ if (tmpcqr != cqr)
+ continue;
+ /* searchcqr is an ERP request for cqr */
+ searchcqr->retries = -1;
+ searchcqr->intrc = -ETIMEDOUT;
+ if (searchcqr->status >= DASD_CQR_QUEUED) {
+ spin_unlock(get_ccwdev_lock(device->cdev));
+ rc = dasd_cancel_req(searchcqr);
+ spin_lock(get_ccwdev_lock(device->cdev));
+ } else if ((searchcqr->status == DASD_CQR_FILLED) ||
+ (searchcqr->status == DASD_CQR_NEED_ERP)) {
+ searchcqr->status = DASD_CQR_TERMINATED;
+ rc = 0;
+ } else if (searchcqr->status == DASD_CQR_IN_ERP) {
+ /*
+ * Shouldn't happen; most recent ERP
+ * request is at the front of queue
+ */
+ continue;
+ }
+ break;
+ }
+ spin_unlock(get_ccwdev_lock(device->cdev));
+ }
+ dasd_schedule_block_bh(block);
+ spin_unlock(&block->queue_lock);
+
+ return rc ? BLK_EH_RESET_TIMER : BLK_EH_NOT_HANDLED;
+}
+
+/*
* Allocate and initialize request queue and default I/O scheduler.
*/
static int dasd_alloc_queue(struct dasd_block *block)
diff --git a/drivers/s390/block/dasd_diag.c b/drivers/s390/block/dasd_diag.c
index 1548422..feca317 100644
--- a/drivers/s390/block/dasd_diag.c
+++ b/drivers/s390/block/dasd_diag.c
@@ -583,7 +583,10 @@ dasd_diag_free_cp(struct dasd_ccw_req *cqr, struct request *req)

static void dasd_diag_handle_terminated_request(struct dasd_ccw_req *cqr)
{
- cqr->status = DASD_CQR_FILLED;
+ if (cqr->retries < 0)
+ cqr->status = DASD_CQR_FAILED;
+ else
+ cqr->status = DASD_CQR_FILLED;
};

/* Fill in IOCTL data for device. */
diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index f4315dc..e25a817 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -2381,6 +2381,10 @@ sleep:

static void dasd_eckd_handle_terminated_request(struct dasd_ccw_req *cqr)
{
+ if (cqr->retries < 0) {
+ cqr->status = DASD_CQR_FAILED;
+ return;
+ }
cqr->status = DASD_CQR_FILLED;
if (cqr->block && (cqr->startdev != cqr->block->base)) {
dasd_eckd_reset_ccw_to_base_io(cqr);
diff --git a/drivers/s390/block/dasd_fba.c b/drivers/s390/block/dasd_fba.c
index d232c83..9cbc8c3 100644
--- a/drivers/s390/block/dasd_fba.c
+++ b/drivers/s390/block/dasd_fba.c
@@ -428,7 +428,10 @@ out:

static void dasd_fba_handle_terminated_request(struct dasd_ccw_req *cqr)
{
- cqr->status = DASD_CQR_FILLED;
+ if (cqr->retries < 0)
+ cqr->status = DASD_CQR_FAILED;
+ else
+ cqr->status = DASD_CQR_FILLED;
};

static int
--
1.7.9.5