From 8360cb5f389ebd36b708978e0f776a285a2deb5a Mon Sep 17 00:00:00 2001 From: Sebastian Ott Date: Thu, 28 Feb 2013 12:07:27 +0100 Subject: s390/scm_blk: fix request number accounting If a block device driver cannot fetch all requests from the blocklayer it's in his responsibility to call the request function at a later time. Normally this would be done after the next irq for the underlying device is handled. However in situations where we have no outstanding request we have to schedule the request function for a later time. This is determined using an internal counter of requests issued to the hardware. In some cases where we give a request back to the block layer unhandled the number of queued requests was not adjusted. Fix this class of failures by adjusting queued_requests in all functions used to give a request back to the block layer. Reviewed-by: Peter Oberparleiter Signed-off-by: Sebastian Ott Signed-off-by: Peter Oberparleiter Signed-off-by: Martin Schwidefsky --- drivers/s390/block/scm_blk.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'drivers/s390/block') diff --git a/drivers/s390/block/scm_blk.c b/drivers/s390/block/scm_blk.c index 9978ad4433c..d9c7e940fa3 100644 --- a/drivers/s390/block/scm_blk.c +++ b/drivers/s390/block/scm_blk.c @@ -195,14 +195,18 @@ void scm_request_requeue(struct scm_request *scmrq) scm_release_cluster(scmrq); blk_requeue_request(bdev->rq, scmrq->request); + atomic_dec(&bdev->queued_reqs); scm_request_done(scmrq); scm_ensure_queue_restart(bdev); } void scm_request_finish(struct scm_request *scmrq) { + struct scm_blk_dev *bdev = scmrq->bdev; + scm_release_cluster(scmrq); blk_end_request_all(scmrq->request, scmrq->error); + atomic_dec(&bdev->queued_reqs); scm_request_done(scmrq); } @@ -231,11 +235,13 @@ static void scm_blk_request(struct request_queue *rq) return; } if (scm_need_cluster_request(scmrq)) { + atomic_inc(&bdev->queued_reqs); blk_start_request(req); scm_initiate_cluster_request(scmrq); return; } scm_request_prepare(scmrq); + atomic_inc(&bdev->queued_reqs); blk_start_request(req); ret = scm_start_aob(scmrq->aob); @@ -244,7 +250,6 @@ static void scm_blk_request(struct request_queue *rq) scm_request_requeue(scmrq); return; } - atomic_inc(&bdev->queued_reqs); } } @@ -310,7 +315,6 @@ static void scm_blk_tasklet(struct scm_blk_dev *bdev) } scm_request_finish(scmrq); - atomic_dec(&bdev->queued_reqs); spin_lock_irqsave(&bdev->lock, flags); } spin_unlock_irqrestore(&bdev->lock, flags); -- cgit v1.2.3 From 93481c90200c50c7874b6a773acc87095ee3907d Mon Sep 17 00:00:00 2001 From: Sebastian Ott Date: Thu, 28 Feb 2013 12:07:38 +0100 Subject: s390/scm_drv: extend notify callback Extend the notify callback of scm_driver by an event parameter to allow to distinguish between different notifications. Reviewed-by: Peter Oberparleiter Signed-off-by: Sebastian Ott Signed-off-by: Peter Oberparleiter Signed-off-by: Martin Schwidefsky --- drivers/s390/block/scm_drv.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) (limited to 'drivers/s390/block') diff --git a/drivers/s390/block/scm_drv.c b/drivers/s390/block/scm_drv.c index 9fa0a908607..ff8558c4fe2 100644 --- a/drivers/s390/block/scm_drv.c +++ b/drivers/s390/block/scm_drv.c @@ -13,12 +13,16 @@ #include #include "scm_blk.h" -static void notify(struct scm_device *scmdev) +static void scm_notify(struct scm_device *scmdev, enum scm_event event) { - pr_info("%lu: The capabilities of the SCM increment changed\n", - (unsigned long) scmdev->address); - SCM_LOG(2, "State changed"); - SCM_LOG_STATE(2, scmdev); + switch (event) { + case SCM_CHANGE: + pr_info("%lu: The capabilities of the SCM increment changed\n", + (unsigned long) scmdev->address); + SCM_LOG(2, "State changed"); + SCM_LOG_STATE(2, scmdev); + break; + } } static int scm_probe(struct scm_device *scmdev) @@ -64,7 +68,7 @@ static struct scm_driver scm_drv = { .name = "scm_block", .owner = THIS_MODULE, }, - .notify = notify, + .notify = scm_notify, .probe = scm_probe, .remove = scm_remove, .handler = scm_blk_irq, -- cgit v1.2.3 From 4fa3c019640ef776e393345ed35d9ec5c51aa3c1 Mon Sep 17 00:00:00 2001 From: Sebastian Ott Date: Thu, 28 Feb 2013 12:07:48 +0100 Subject: 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 Signed-off-by: Sebastian Ott Signed-off-by: Peter Oberparleiter Signed-off-by: Martin Schwidefsky --- drivers/s390/block/scm_blk.c | 61 ++++++++++++++++++++++++++++++++++++++++---- drivers/s390/block/scm_blk.h | 2 ++ 2 files changed, 58 insertions(+), 5 deletions(-) (limited to 'drivers/s390/block') diff --git a/drivers/s390/block/scm_blk.c b/drivers/s390/block/scm_blk.c index d9c7e940fa3..5ac9c935c15 100644 --- a/drivers/s390/block/scm_blk.c +++ b/drivers/s390/block/scm_blk.c @@ -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; diff --git a/drivers/s390/block/scm_blk.h b/drivers/s390/block/scm_blk.h index 3c1ccf49464..8b387b32fd6 100644 --- a/drivers/s390/block/scm_blk.h +++ b/drivers/s390/block/scm_blk.h @@ -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 *); -- cgit v1.2.3 From aebfa669d9fe77876f120d3d9a28fee240fe5a8e Mon Sep 17 00:00:00 2001 From: Sebastian Ott Date: Thu, 28 Feb 2013 12:07:55 +0100 Subject: s390/scm: process availability Let the bus code process scm availability information and notify scm device drivers about the new state. Reviewed-by: Peter Oberparleiter Signed-off-by: Sebastian Ott Signed-off-by: Peter Oberparleiter Signed-off-by: Martin Schwidefsky --- drivers/s390/block/scm_drv.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'drivers/s390/block') diff --git a/drivers/s390/block/scm_drv.c b/drivers/s390/block/scm_drv.c index ff8558c4fe2..5f6180d6ff0 100644 --- a/drivers/s390/block/scm_drv.c +++ b/drivers/s390/block/scm_drv.c @@ -15,6 +15,8 @@ static void scm_notify(struct scm_device *scmdev, enum scm_event event) { + struct scm_blk_dev *bdev = dev_get_drvdata(&scmdev->dev); + switch (event) { case SCM_CHANGE: pr_info("%lu: The capabilities of the SCM increment changed\n", @@ -22,6 +24,11 @@ static void scm_notify(struct scm_device *scmdev, enum scm_event event) SCM_LOG(2, "State changed"); SCM_LOG_STATE(2, scmdev); break; + case SCM_AVAIL: + SCM_LOG(2, "Increment available"); + SCM_LOG_STATE(2, scmdev); + scm_blk_set_available(bdev); + break; } } -- cgit v1.2.3