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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>
This commit is contained in:
Sebastian Ott 2013-02-28 12:07:48 +01:00 committed by Martin Schwidefsky
parent 93481c9020
commit 4fa3c01964
3 changed files with 60 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/s390/include/asm/eadm.h
View File

@ -34,6 +34,8 @@ struct arsb {
u32 reserved[4];
} __packed;
#define EQC_WR_PROHIBIT 22
struct msb {
u8 fmt:4;
u8 oc:4;

61
drivers/s390/block/scm_blk.c
View File

@ -135,6 +135,11 @@ static const struct block_device_operations scm_blk_devops = {
.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 @@ static void scm_blk_request(struct request_queue *rq)
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 @@ void scm_blk_irq(struct scm_device *scmdev, void *data, int error)
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 @@ static void scm_blk_tasklet(struct scm_blk_dev *bdev)
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 @@ int scm_blk_dev_setup(struct scm_blk_dev *bdev, struct scm_device *scmdev)
}
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 @@ void scm_blk_dev_cleanup(struct scm_blk_dev *bdev)
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;

2
drivers/s390/block/scm_blk.h
View File

@ -21,6 +21,7 @@ struct scm_blk_dev {
spinlock_t rq_lock; /* guard the request queue */
spinlock_t lock; /* guard the rest of the blockdev */
atomic_t queued_reqs;
enum {SCM_OPER, SCM_WR_PROHIBIT} state;
struct list_head finished_requests;
#ifdef CONFIG_SCM_BLOCK_CLUSTER_WRITE
struct list_head cluster_list;
@ -48,6 +49,7 @@ struct scm_request {
int scm_blk_dev_setup(struct scm_blk_dev *, struct scm_device *);
void scm_blk_dev_cleanup(struct scm_blk_dev *);
void scm_blk_set_available(struct scm_blk_dev *);
void scm_blk_irq(struct scm_device *, void *, int);
void scm_request_finish(struct scm_request *);