s390/scm_blk: suspend writes
Stop writing to scm after certain error conditions such as a concurrent
firmware upgrade. Resume to normal state once scm_blk_set_available is
called (due to an scm availability notification).
Reviewed-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/block/scm_blk.c b/drivers/s390/block/scm_blk.c
index d9c7e94..5ac9c93 100644
--- a/drivers/s390/block/scm_blk.c
+++ b/drivers/s390/block/scm_blk.c
@@ -135,6 +135,11 @@
.release = scm_release,
};
+static bool scm_permit_request(struct scm_blk_dev *bdev, struct request *req)
+{
+ return rq_data_dir(req) != WRITE || bdev->state != SCM_WR_PROHIBIT;
+}
+
static void scm_request_prepare(struct scm_request *scmrq)
{
struct scm_blk_dev *bdev = scmrq->bdev;
@@ -222,6 +227,10 @@
if (req->cmd_type != REQ_TYPE_FS)
continue;
+ if (!scm_permit_request(bdev, req)) {
+ scm_ensure_queue_restart(bdev);
+ return;
+ }
scmrq = scm_request_fetch();
if (!scmrq) {
SCM_LOG(5, "no request");
@@ -285,6 +294,38 @@
tasklet_hi_schedule(&bdev->tasklet);
}
+static void scm_blk_handle_error(struct scm_request *scmrq)
+{
+ struct scm_blk_dev *bdev = scmrq->bdev;
+ unsigned long flags;
+
+ if (scmrq->error != -EIO)
+ goto restart;
+
+ /* For -EIO the response block is valid. */
+ switch (scmrq->aob->response.eqc) {
+ case EQC_WR_PROHIBIT:
+ spin_lock_irqsave(&bdev->lock, flags);
+ if (bdev->state != SCM_WR_PROHIBIT)
+ pr_info("%lu: Write access to the SCM increment is suspended\n",
+ (unsigned long) bdev->scmdev->address);
+ bdev->state = SCM_WR_PROHIBIT;
+ spin_unlock_irqrestore(&bdev->lock, flags);
+ goto requeue;
+ default:
+ break;
+ }
+
+restart:
+ if (!scm_start_aob(scmrq->aob))
+ return;
+
+requeue:
+ spin_lock_irqsave(&bdev->rq_lock, flags);
+ scm_request_requeue(scmrq);
+ spin_unlock_irqrestore(&bdev->rq_lock, flags);
+}
+
static void scm_blk_tasklet(struct scm_blk_dev *bdev)
{
struct scm_request *scmrq;
@@ -298,11 +339,8 @@
spin_unlock_irqrestore(&bdev->lock, flags);
if (scmrq->error && scmrq->retries-- > 0) {
- if (scm_start_aob(scmrq->aob)) {
- spin_lock_irqsave(&bdev->rq_lock, flags);
- scm_request_requeue(scmrq);
- spin_unlock_irqrestore(&bdev->rq_lock, flags);
- }
+ scm_blk_handle_error(scmrq);
+
/* Request restarted or requeued, handle next. */
spin_lock_irqsave(&bdev->lock, flags);
continue;
@@ -336,6 +374,7 @@
}
bdev->scmdev = scmdev;
+ bdev->state = SCM_OPER;
spin_lock_init(&bdev->rq_lock);
spin_lock_init(&bdev->lock);
INIT_LIST_HEAD(&bdev->finished_requests);
@@ -400,6 +439,18 @@
put_disk(bdev->gendisk);
}
+void scm_blk_set_available(struct scm_blk_dev *bdev)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&bdev->lock, flags);
+ if (bdev->state == SCM_WR_PROHIBIT)
+ pr_info("%lu: Write access to the SCM increment is restored\n",
+ (unsigned long) bdev->scmdev->address);
+ bdev->state = SCM_OPER;
+ spin_unlock_irqrestore(&bdev->lock, flags);
+}
+
static int __init scm_blk_init(void)
{
int ret = -EINVAL;