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Commit 4fa3c019 authored by Sebastian Ott's avatar Sebastian Ott Committed by Martin Schwidefsky
Browse files

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: default avatarPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: default avatarSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: default avatarPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 93481c90

arch/s390/include/asm/eadm.h

+2 −0
Original line number Diff line number Diff line
@@ -34,6 +34,8 @@ struct arsb { 
	u32 reserved[4];

} __packed;



#define EQC_WR_PROHIBIT 22



struct msb {

	u8 fmt:4;

	u8 oc:4;

drivers/s390/block/scm_blk.c

+56 −5
Original line number Diff line number Diff line
@@ -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;

drivers/s390/block/scm_blk.h

+2 −0
Original line number Diff line number Diff line
@@ -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 *);