[mirror_ubuntu-artful-kernel.git] / drivers / s390 / block / scm_blk.c

/*
 * Block driver for s390 storage class memory.
 *
 * Copyright IBM Corp. 2012
 * Author(s): Sebastian Ott <sebott@linux.vnet.ibm.com>
 */

#define KMSG_COMPONENT "scm_block"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/mempool.h>
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/genhd.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <asm/eadm.h>
#include "scm_blk.h"

debug_info_t *scm_debug;
static int scm_major;
static mempool_t *aidaw_pool;
static DEFINE_SPINLOCK(list_lock);
static LIST_HEAD(inactive_requests);
static unsigned int nr_requests = 64;
static unsigned int nr_requests_per_io = 8;
static atomic_t nr_devices = ATOMIC_INIT(0);
module_param(nr_requests, uint, S_IRUGO);
MODULE_PARM_DESC(nr_requests, "Number of parallel requests.");

module_param(nr_requests_per_io, uint, S_IRUGO);
MODULE_PARM_DESC(nr_requests_per_io, "Number of requests per IO.");

MODULE_DESCRIPTION("Block driver for s390 storage class memory.");
MODULE_LICENSE("GPL");
MODULE_ALIAS("scm:scmdev*");

static void __scm_free_rq(struct scm_request *scmrq)
{
	struct aob_rq_header *aobrq = to_aobrq(scmrq);

	free_page((unsigned long) scmrq->aob);
	__scm_free_rq_cluster(scmrq);
	kfree(scmrq->request);
	kfree(aobrq);
}

static void scm_free_rqs(void)
{
	struct list_head *iter, *safe;
	struct scm_request *scmrq;

	spin_lock_irq(&list_lock);
	list_for_each_safe(iter, safe, &inactive_requests) {
		scmrq = list_entry(iter, struct scm_request, list);
		list_del(&scmrq->list);
		__scm_free_rq(scmrq);
	}
	spin_unlock_irq(&list_lock);

	mempool_destroy(aidaw_pool);
}

static int __scm_alloc_rq(void)
{
	struct aob_rq_header *aobrq;
	struct scm_request *scmrq;

	aobrq = kzalloc(sizeof(*aobrq) + sizeof(*scmrq), GFP_KERNEL);
	if (!aobrq)
		return -ENOMEM;

	scmrq = (void *) aobrq->data;
	scmrq->aob = (void *) get_zeroed_page(GFP_DMA);
	if (!scmrq->aob)
		goto free;

	scmrq->request = kcalloc(nr_requests_per_io, sizeof(scmrq->request[0]),
				 GFP_KERNEL);
	if (!scmrq->request)
		goto free;

	if (__scm_alloc_rq_cluster(scmrq))
		goto free;

	INIT_LIST_HEAD(&scmrq->list);
	spin_lock_irq(&list_lock);
	list_add(&scmrq->list, &inactive_requests);
	spin_unlock_irq(&list_lock);

	return 0;
free:
	__scm_free_rq(scmrq);
	return -ENOMEM;
}

static int scm_alloc_rqs(unsigned int nrqs)
{
	int ret = 0;

	aidaw_pool = mempool_create_page_pool(max(nrqs/8, 1U), 0);
	if (!aidaw_pool)
		return -ENOMEM;

	while (nrqs-- && !ret)
		ret = __scm_alloc_rq();

	return ret;
}

static struct scm_request *scm_request_fetch(void)
{
	struct scm_request *scmrq = NULL;

	spin_lock(&list_lock);
	if (list_empty(&inactive_requests))
		goto out;
	scmrq = list_first_entry(&inactive_requests, struct scm_request, list);
	list_del(&scmrq->list);
out:
	spin_unlock(&list_lock);
	return scmrq;
}

static void scm_request_done(struct scm_request *scmrq)
{
	unsigned long flags;
	struct msb *msb;
	u64 aidaw;
	int i;

	for (i = 0; i < nr_requests_per_io && scmrq->request[i]; i++) {
		msb = &scmrq->aob->msb[i];
		aidaw = msb->data_addr;

		if ((msb->flags & MSB_FLAG_IDA) && aidaw &&
		    IS_ALIGNED(aidaw, PAGE_SIZE))
			mempool_free(virt_to_page(aidaw), aidaw_pool);
	}

	spin_lock_irqsave(&list_lock, flags);
	list_add(&scmrq->list, &inactive_requests);
	spin_unlock_irqrestore(&list_lock, flags);
}

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 inline struct aidaw *scm_aidaw_alloc(void)
{
	struct page *page = mempool_alloc(aidaw_pool, GFP_ATOMIC);

	return page ? page_address(page) : NULL;
}

static inline unsigned long scm_aidaw_bytes(struct aidaw *aidaw)
{
	unsigned long _aidaw = (unsigned long) aidaw;
	unsigned long bytes = ALIGN(_aidaw, PAGE_SIZE) - _aidaw;

	return (bytes / sizeof(*aidaw)) * PAGE_SIZE;
}

struct aidaw *scm_aidaw_fetch(struct scm_request *scmrq, unsigned int bytes)
{
	struct aidaw *aidaw;

	if (scm_aidaw_bytes(scmrq->next_aidaw) >= bytes)
		return scmrq->next_aidaw;

	aidaw = scm_aidaw_alloc();
	if (aidaw)
		memset(aidaw, 0, PAGE_SIZE);
	return aidaw;
}

static int scm_request_prepare(struct scm_request *scmrq)
{
	struct scm_blk_dev *bdev = scmrq->bdev;
	struct scm_device *scmdev = bdev->gendisk->private_data;
	int pos = scmrq->aob->request.msb_count;
	struct msb *msb = &scmrq->aob->msb[pos];
	struct request *req = scmrq->request[pos];
	struct req_iterator iter;
	struct aidaw *aidaw;
	struct bio_vec bv;

	aidaw = scm_aidaw_fetch(scmrq, blk_rq_bytes(req));
	if (!aidaw)
		return -ENOMEM;

	msb->bs = MSB_BS_4K;
	scmrq->aob->request.msb_count++;
	msb->scm_addr = scmdev->address + ((u64) blk_rq_pos(req) << 9);
	msb->oc = (rq_data_dir(req) == READ) ? MSB_OC_READ : MSB_OC_WRITE;
	msb->flags |= MSB_FLAG_IDA;
	msb->data_addr = (u64) aidaw;

	rq_for_each_segment(bv, req, iter) {
		WARN_ON(bv.bv_offset);
		msb->blk_count += bv.bv_len >> 12;
		aidaw->data_addr = (u64) page_address(bv.bv_page);
		aidaw++;
	}

	scmrq->next_aidaw = aidaw;
	return 0;
}

static inline void scm_request_set(struct scm_request *scmrq,
				   struct request *req)
{
	scmrq->request[scmrq->aob->request.msb_count] = req;
}

static inline void scm_request_init(struct scm_blk_dev *bdev,
				    struct scm_request *scmrq)
{
	struct aob_rq_header *aobrq = to_aobrq(scmrq);
	struct aob *aob = scmrq->aob;

	memset(scmrq->request, 0,
	       nr_requests_per_io * sizeof(scmrq->request[0]));
	memset(aob, 0, sizeof(*aob));
	aobrq->scmdev = bdev->scmdev;
	aob->request.cmd_code = ARQB_CMD_MOVE;
	aob->request.data = (u64) aobrq;
	scmrq->bdev = bdev;
	scmrq->retries = 4;
	scmrq->error = 0;
	/* We don't use all msbs - place aidaws at the end of the aob page. */
	scmrq->next_aidaw = (void *) &aob->msb[nr_requests_per_io];
	scm_request_cluster_init(scmrq);
}

static void scm_ensure_queue_restart(struct scm_blk_dev *bdev)
{
	if (atomic_read(&bdev->queued_reqs)) {
		/* Queue restart is triggered by the next interrupt. */
		return;
	}
	blk_delay_queue(bdev->rq, SCM_QUEUE_DELAY);
}

void scm_request_requeue(struct scm_request *scmrq)
{
	struct scm_blk_dev *bdev = scmrq->bdev;
	int i;

	scm_release_cluster(scmrq);
	for (i = 0; i < nr_requests_per_io && scmrq->request[i]; i++)
		blk_requeue_request(bdev->rq, scmrq->request[i]);

	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;
	int i;

	scm_release_cluster(scmrq);
	for (i = 0; i < nr_requests_per_io && scmrq->request[i]; i++)
		blk_end_request_all(scmrq->request[i], scmrq->error);

	atomic_dec(&bdev->queued_reqs);
	scm_request_done(scmrq);
}

static int scm_request_start(struct scm_request *scmrq)
{
	struct scm_blk_dev *bdev = scmrq->bdev;
	int ret;

	atomic_inc(&bdev->queued_reqs);
	if (!scmrq->aob->request.msb_count) {
		scm_request_requeue(scmrq);
		return -EINVAL;
	}

	ret = eadm_start_aob(scmrq->aob);
	if (ret) {
		SCM_LOG(5, "no subchannel");
		scm_request_requeue(scmrq);
	}
	return ret;
}

static void scm_blk_request(struct request_queue *rq)
{
	struct scm_device *scmdev = rq->queuedata;
	struct scm_blk_dev *bdev = dev_get_drvdata(&scmdev->dev);
	struct scm_request *scmrq = NULL;
	struct request *req;

	while ((req = blk_peek_request(rq))) {
		if (!scm_permit_request(bdev, req))
			goto out;

		if (!scmrq) {
			scmrq = scm_request_fetch();
			if (!scmrq) {
				SCM_LOG(5, "no request");
				goto out;
			}
			scm_request_init(bdev, scmrq);
		}
		scm_request_set(scmrq, req);

		if (!scm_reserve_cluster(scmrq)) {
			SCM_LOG(5, "cluster busy");
			scm_request_set(scmrq, NULL);
			if (scmrq->aob->request.msb_count)
				goto out;

			scm_request_done(scmrq);
			return;
		}

		if (scm_need_cluster_request(scmrq)) {
			if (scmrq->aob->request.msb_count) {
				/* Start cluster requests separately. */
				scm_request_set(scmrq, NULL);
				if (scm_request_start(scmrq))
					return;
			} else {
				atomic_inc(&bdev->queued_reqs);
				blk_start_request(req);
				scm_initiate_cluster_request(scmrq);
			}
			scmrq = NULL;
			continue;
		}

		if (scm_request_prepare(scmrq)) {
			SCM_LOG(5, "aidaw alloc failed");
			scm_request_set(scmrq, NULL);
			goto out;
		}
		blk_start_request(req);

		if (scmrq->aob->request.msb_count < nr_requests_per_io)
			continue;

		if (scm_request_start(scmrq))
			return;

		scmrq = NULL;
	}
out:
	if (scmrq)
		scm_request_start(scmrq);
	else
		scm_ensure_queue_restart(bdev);
}

static void __scmrq_log_error(struct scm_request *scmrq)
{
	struct aob *aob = scmrq->aob;

	if (scmrq->error == -ETIMEDOUT)
		SCM_LOG(1, "Request timeout");
	else {
		SCM_LOG(1, "Request error");
		SCM_LOG_HEX(1, &aob->response, sizeof(aob->response));
	}
	if (scmrq->retries)
		SCM_LOG(1, "Retry request");
	else
		pr_err("An I/O operation to SCM failed with rc=%d\n",
		       scmrq->error);
}

void scm_blk_irq(struct scm_device *scmdev, void *data, int error)
{
	struct scm_request *scmrq = data;
	struct scm_blk_dev *bdev = scmrq->bdev;

	scmrq->error = error;
	if (error)
		__scmrq_log_error(scmrq);

	spin_lock(&bdev->lock);
	list_add_tail(&scmrq->list, &bdev->finished_requests);
	spin_unlock(&bdev->lock);
	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("%lx: 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 (!eadm_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;
	unsigned long flags;

	spin_lock_irqsave(&bdev->lock, flags);
	while (!list_empty(&bdev->finished_requests)) {
		scmrq = list_first_entry(&bdev->finished_requests,
					 struct scm_request, list);
		list_del(&scmrq->list);
		spin_unlock_irqrestore(&bdev->lock, flags);

		if (scmrq->error && scmrq->retries-- > 0) {
			scm_blk_handle_error(scmrq);

			/* Request restarted or requeued, handle next. */
			spin_lock_irqsave(&bdev->lock, flags);
			continue;
		}

		if (scm_test_cluster_request(scmrq)) {
			scm_cluster_request_irq(scmrq);
			spin_lock_irqsave(&bdev->lock, flags);
			continue;
		}

		scm_request_finish(scmrq);
		spin_lock_irqsave(&bdev->lock, flags);
	}
	spin_unlock_irqrestore(&bdev->lock, flags);
	/* Look out for more requests. */
	blk_run_queue(bdev->rq);
}

static const struct block_device_operations scm_blk_devops = {
	.owner = THIS_MODULE,
};

int scm_blk_dev_setup(struct scm_blk_dev *bdev, struct scm_device *scmdev)
{
	struct request_queue *rq;
	int len, ret = -ENOMEM;
	unsigned int devindex, nr_max_blk;

	devindex = atomic_inc_return(&nr_devices) - 1;
	/* scma..scmz + scmaa..scmzz */
	if (devindex > 701) {
		ret = -ENODEV;
		goto out;
	}

	bdev->scmdev = scmdev;
	bdev->state = SCM_OPER;
	spin_lock_init(&bdev->rq_lock);
	spin_lock_init(&bdev->lock);
	INIT_LIST_HEAD(&bdev->finished_requests);
	atomic_set(&bdev->queued_reqs, 0);
	tasklet_init(&bdev->tasklet,
		     (void (*)(unsigned long)) scm_blk_tasklet,
		     (unsigned long) bdev);

	rq = blk_init_queue(scm_blk_request, &bdev->rq_lock);
	if (!rq)
		goto out;

	bdev->rq = rq;
	nr_max_blk = min(scmdev->nr_max_block,
			 (unsigned int) (PAGE_SIZE / sizeof(struct aidaw)));

	blk_queue_logical_block_size(rq, 1 << 12);
	blk_queue_max_hw_sectors(rq, nr_max_blk << 3); /* 8 * 512 = blk_size */
	blk_queue_max_segments(rq, nr_max_blk);
	queue_flag_set_unlocked(QUEUE_FLAG_NONROT, rq);
	queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, rq);
	scm_blk_dev_cluster_setup(bdev);

	bdev->gendisk = alloc_disk(SCM_NR_PARTS);
	if (!bdev->gendisk)
		goto out_queue;

	rq->queuedata = scmdev;
	bdev->gendisk->private_data = scmdev;
	bdev->gendisk->fops = &scm_blk_devops;
	bdev->gendisk->queue = rq;
	bdev->gendisk->major = scm_major;
	bdev->gendisk->first_minor = devindex * SCM_NR_PARTS;

	len = snprintf(bdev->gendisk->disk_name, DISK_NAME_LEN, "scm");
	if (devindex > 25) {
		len += snprintf(bdev->gendisk->disk_name + len,
				DISK_NAME_LEN - len, "%c",
				'a' + (devindex / 26) - 1);
		devindex = devindex % 26;
	}
	snprintf(bdev->gendisk->disk_name + len, DISK_NAME_LEN - len, "%c",
		 'a' + devindex);

	/* 512 byte sectors */
	set_capacity(bdev->gendisk, scmdev->size >> 9);
	device_add_disk(&scmdev->dev, bdev->gendisk);
	return 0;

out_queue:
	blk_cleanup_queue(rq);
out:
	atomic_dec(&nr_devices);
	return ret;
}

void scm_blk_dev_cleanup(struct scm_blk_dev *bdev)
{
	tasklet_kill(&bdev->tasklet);
	del_gendisk(bdev->gendisk);
	blk_cleanup_queue(bdev->gendisk->queue);
	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("%lx: 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 bool __init scm_blk_params_valid(void)
{
	if (!nr_requests_per_io || nr_requests_per_io > 64)
		return false;

	return scm_cluster_size_valid();
}

static int __init scm_blk_init(void)
{
	int ret = -EINVAL;

	if (!scm_blk_params_valid())
		goto out;

	ret = register_blkdev(0, "scm");
	if (ret < 0)
		goto out;

	scm_major = ret;
	ret = scm_alloc_rqs(nr_requests);
	if (ret)
		goto out_free;

	scm_debug = debug_register("scm_log", 16, 1, 16);
	if (!scm_debug) {
		ret = -ENOMEM;
		goto out_free;
	}

	debug_register_view(scm_debug, &debug_hex_ascii_view);
	debug_set_level(scm_debug, 2);

	ret = scm_drv_init();
	if (ret)
		goto out_dbf;

	return ret;

out_dbf:
	debug_unregister(scm_debug);
out_free:
	scm_free_rqs();
	unregister_blkdev(scm_major, "scm");
out:
	return ret;
}
module_init(scm_blk_init);

static void __exit scm_blk_cleanup(void)
{
	scm_drv_cleanup();
	debug_unregister(scm_debug);
	scm_free_rqs();
	unregister_blkdev(scm_major, "scm");
}
module_exit(scm_blk_cleanup);
Commit	Line	Data
f30664e2 SO	1	/*
	2	* Block driver for s390 storage class memory.
	3	*
	4	* Copyright IBM Corp. 2012
	5	* Author(s): Sebastian Ott <sebott@linux.vnet.ibm.com>
	6	*/
	7
	8	#define KMSG_COMPONENT "scm_block"
	9	#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
	10
	11	#include <linux/interrupt.h>
	12	#include <linux/spinlock.h>
9d4df77f	13	#include <linux/mempool.h>
f30664e2 SO	14	#include <linux/module.h>
	15	#include <linux/blkdev.h>
	16	#include <linux/genhd.h>
	17	#include <linux/slab.h>
	18	#include <linux/list.h>
	19	#include <asm/eadm.h>
	20	#include "scm_blk.h"
	21
	22	debug_info_t *scm_debug;
	23	static int scm_major;
9d4df77f	24	static mempool_t *aidaw_pool;
f30664e2 SO	25	static DEFINE_SPINLOCK(list_lock);
	26	static LIST_HEAD(inactive_requests);
	27	static unsigned int nr_requests = 64;
8622384f	28	static unsigned int nr_requests_per_io = 8;
f30664e2 SO	29	static atomic_t nr_devices = ATOMIC_INIT(0);
	30	module_param(nr_requests, uint, S_IRUGO);
	31	MODULE_PARM_DESC(nr_requests, "Number of parallel requests.");
	32
8622384f SO	33	module_param(nr_requests_per_io, uint, S_IRUGO);
	34	MODULE_PARM_DESC(nr_requests_per_io, "Number of requests per IO.");
	35
f30664e2 SO	36	MODULE_DESCRIPTION("Block driver for s390 storage class memory.");
	37	MODULE_LICENSE("GPL");
	38	MODULE_ALIAS("scm:scmdev*");
	39
	40	static void __scm_free_rq(struct scm_request *scmrq)
	41	{
	42	struct aob_rq_header *aobrq = to_aobrq(scmrq);
	43
	44	free_page((unsigned long) scmrq->aob);
0d804b20	45	__scm_free_rq_cluster(scmrq);
8622384f	46	kfree(scmrq->request);
f30664e2 SO	47	kfree(aobrq);
	48	}
	49
	50	static void scm_free_rqs(void)
	51	{
	52	struct list_head iter, safe;
	53	struct scm_request *scmrq;
	54
	55	spin_lock_irq(&list_lock);
	56	list_for_each_safe(iter, safe, &inactive_requests) {
	57	scmrq = list_entry(iter, struct scm_request, list);
	58	list_del(&scmrq->list);
	59	__scm_free_rq(scmrq);
	60	}
	61	spin_unlock_irq(&list_lock);
9d4df77f SO	62
9d4df77f SO	63	mempool_destroy(aidaw_pool);
f30664e2 SO	64	}
	65
	66	static int __scm_alloc_rq(void)
	67	{
	68	struct aob_rq_header *aobrq;
	69	struct scm_request *scmrq;
	70
	71	aobrq = kzalloc(sizeof(aobrq) + sizeof(scmrq), GFP_KERNEL);
	72	if (!aobrq)
	73	return -ENOMEM;
	74
	75	scmrq = (void *) aobrq->data;
f30664e2	76	scmrq->aob = (void *) get_zeroed_page(GFP_DMA);
8622384f SO	77	if (!scmrq->aob)
8622384f SO	78	goto free;
0d804b20	79
8622384f SO	80	scmrq->request = kcalloc(nr_requests_per_io, sizeof(scmrq->request[0]),
	81	GFP_KERNEL);
	82	if (!scmrq->request)
	83	goto free;
	84
	85	if (__scm_alloc_rq_cluster(scmrq))
	86	goto free;
0d804b20	87
f30664e2 SO	88	INIT_LIST_HEAD(&scmrq->list);
	89	spin_lock_irq(&list_lock);
	90	list_add(&scmrq->list, &inactive_requests);
	91	spin_unlock_irq(&list_lock);
	92
	93	return 0;
8622384f SO	94	free:
	95	__scm_free_rq(scmrq);
	96	return -ENOMEM;
f30664e2 SO	97	}
	98
	99	static int scm_alloc_rqs(unsigned int nrqs)
	100	{
	101	int ret = 0;
	102
9d4df77f SO	103	aidaw_pool = mempool_create_page_pool(max(nrqs/8, 1U), 0);
	104	if (!aidaw_pool)
	105	return -ENOMEM;
	106
f30664e2 SO	107	while (nrqs-- && !ret)
	108	ret = __scm_alloc_rq();
	109
	110	return ret;
	111	}
	112
	113	static struct scm_request *scm_request_fetch(void)
	114	{
	115	struct scm_request *scmrq = NULL;
	116
	117	spin_lock(&list_lock);
	118	if (list_empty(&inactive_requests))
	119	goto out;
	120	scmrq = list_first_entry(&inactive_requests, struct scm_request, list);
	121	list_del(&scmrq->list);
	122	out:
	123	spin_unlock(&list_lock);
	124	return scmrq;
	125	}
	126
	127	static void scm_request_done(struct scm_request *scmrq)
	128	{
	129	unsigned long flags;
bbc610a9 SO	130	struct msb *msb;
	131	u64 aidaw;
	132	int i;
f30664e2	133
8622384f	134	for (i = 0; i < nr_requests_per_io && scmrq->request[i]; i++) {
bbc610a9 SO	135	msb = &scmrq->aob->msb[i];
	136	aidaw = msb->data_addr;
	137
	138	if ((msb->flags & MSB_FLAG_IDA) && aidaw &&
	139	IS_ALIGNED(aidaw, PAGE_SIZE))
	140	mempool_free(virt_to_page(aidaw), aidaw_pool);
	141	}
9d4df77f	142
f30664e2 SO	143	spin_lock_irqsave(&list_lock, flags);
	144	list_add(&scmrq->list, &inactive_requests);
	145	spin_unlock_irqrestore(&list_lock, flags);
	146	}
	147
4fa3c019 SO	148	static bool scm_permit_request(struct scm_blk_dev bdev, struct request req)
	149	{
	150	return rq_data_dir(req) != WRITE \|\| bdev->state != SCM_WR_PROHIBIT;
	151	}
	152
de88d0d2	153	static inline struct aidaw *scm_aidaw_alloc(void)
9d4df77f SO	154	{
	155	struct page *page = mempool_alloc(aidaw_pool, GFP_ATOMIC);
	156
	157	return page ? page_address(page) : NULL;
	158	}
	159
de88d0d2 SO	160	static inline unsigned long scm_aidaw_bytes(struct aidaw *aidaw)
	161	{
	162	unsigned long _aidaw = (unsigned long) aidaw;
	163	unsigned long bytes = ALIGN(_aidaw, PAGE_SIZE) - _aidaw;
	164
	165	return (bytes / sizeof(aidaw)) PAGE_SIZE;
	166	}
	167
	168	struct aidaw scm_aidaw_fetch(struct scm_request scmrq, unsigned int bytes)
	169	{
	170	struct aidaw *aidaw;
	171
	172	if (scm_aidaw_bytes(scmrq->next_aidaw) >= bytes)
	173	return scmrq->next_aidaw;
	174
	175	aidaw = scm_aidaw_alloc();
	176	if (aidaw)
	177	memset(aidaw, 0, PAGE_SIZE);
	178	return aidaw;
	179	}
	180
9d4df77f	181	static int scm_request_prepare(struct scm_request *scmrq)
f30664e2 SO	182	{
	183	struct scm_blk_dev *bdev = scmrq->bdev;
	184	struct scm_device *scmdev = bdev->gendisk->private_data;
bbc610a9 SO	185	int pos = scmrq->aob->request.msb_count;
	186	struct msb *msb = &scmrq->aob->msb[pos];
	187	struct request *req = scmrq->request[pos];
f30664e2	188	struct req_iterator iter;
de88d0d2	189	struct aidaw *aidaw;
7988613b	190	struct bio_vec bv;
f30664e2	191
bbc610a9	192	aidaw = scm_aidaw_fetch(scmrq, blk_rq_bytes(req));
9d4df77f SO	193	if (!aidaw)
	194	return -ENOMEM;
	195
f30664e2	196	msb->bs = MSB_BS_4K;
bbc610a9 SO	197	scmrq->aob->request.msb_count++;
	198	msb->scm_addr = scmdev->address + ((u64) blk_rq_pos(req) << 9);
	199	msb->oc = (rq_data_dir(req) == READ) ? MSB_OC_READ : MSB_OC_WRITE;
f30664e2 SO	200	msb->flags \|= MSB_FLAG_IDA;
	201	msb->data_addr = (u64) aidaw;
	202
bbc610a9	203	rq_for_each_segment(bv, req, iter) {
7988613b KO	204	WARN_ON(bv.bv_offset);
	205	msb->blk_count += bv.bv_len >> 12;
	206	aidaw->data_addr = (u64) page_address(bv.bv_page);
f30664e2 SO	207	aidaw++;
f30664e2 SO	208	}
9d4df77f	209
bbc610a9	210	scmrq->next_aidaw = aidaw;
9d4df77f	211	return 0;
f30664e2 SO	212	}
f30664e2 SO	213
bbc610a9 SO	214	static inline void scm_request_set(struct scm_request *scmrq,
	215	struct request *req)
	216	{
	217	scmrq->request[scmrq->aob->request.msb_count] = req;
	218	}
	219
f30664e2	220	static inline void scm_request_init(struct scm_blk_dev *bdev,
bbc610a9	221	struct scm_request *scmrq)
f30664e2 SO	222	{
	223	struct aob_rq_header *aobrq = to_aobrq(scmrq);
	224	struct aob *aob = scmrq->aob;
	225
8622384f SO	226	memset(scmrq->request, 0,
8622384f SO	227	nr_requests_per_io * sizeof(scmrq->request[0]));
f30664e2	228	memset(aob, 0, sizeof(*aob));
f30664e2 SO	229	aobrq->scmdev = bdev->scmdev;
	230	aob->request.cmd_code = ARQB_CMD_MOVE;
	231	aob->request.data = (u64) aobrq;
f30664e2 SO	232	scmrq->bdev = bdev;
	233	scmrq->retries = 4;
	234	scmrq->error = 0;
de88d0d2	235	/* We don't use all msbs - place aidaws at the end of the aob page. */
8622384f	236	scmrq->next_aidaw = (void *) &aob->msb[nr_requests_per_io];
0d804b20	237	scm_request_cluster_init(scmrq);
f30664e2 SO	238	}
	239
	240	static void scm_ensure_queue_restart(struct scm_blk_dev *bdev)
	241	{
	242	if (atomic_read(&bdev->queued_reqs)) {
	243	/* Queue restart is triggered by the next interrupt. */
	244	return;
	245	}
	246	blk_delay_queue(bdev->rq, SCM_QUEUE_DELAY);
	247	}
	248
0d804b20	249	void scm_request_requeue(struct scm_request *scmrq)
f30664e2 SO	250	{
f30664e2 SO	251	struct scm_blk_dev *bdev = scmrq->bdev;
bbc610a9	252	int i;
f30664e2	253
0d804b20	254	scm_release_cluster(scmrq);
8622384f	255	for (i = 0; i < nr_requests_per_io && scmrq->request[i]; i++)
bbc610a9 SO	256	blk_requeue_request(bdev->rq, scmrq->request[i]);
bbc610a9 SO	257
8360cb5f	258	atomic_dec(&bdev->queued_reqs);
f30664e2 SO	259	scm_request_done(scmrq);
	260	scm_ensure_queue_restart(bdev);
	261	}
	262
0d804b20	263	void scm_request_finish(struct scm_request *scmrq)
f30664e2	264	{
8360cb5f	265	struct scm_blk_dev *bdev = scmrq->bdev;
bbc610a9	266	int i;
8360cb5f	267
0d804b20	268	scm_release_cluster(scmrq);
8622384f	269	for (i = 0; i < nr_requests_per_io && scmrq->request[i]; i++)
bbc610a9 SO	270	blk_end_request_all(scmrq->request[i], scmrq->error);
bbc610a9 SO	271
8360cb5f	272	atomic_dec(&bdev->queued_reqs);
f30664e2 SO	273	scm_request_done(scmrq);
	274	}
	275
bbc610a9 SO	276	static int scm_request_start(struct scm_request *scmrq)
	277	{
	278	struct scm_blk_dev *bdev = scmrq->bdev;
	279	int ret;
	280
	281	atomic_inc(&bdev->queued_reqs);
	282	if (!scmrq->aob->request.msb_count) {
	283	scm_request_requeue(scmrq);
	284	return -EINVAL;
	285	}
	286
	287	ret = eadm_start_aob(scmrq->aob);
	288	if (ret) {
	289	SCM_LOG(5, "no subchannel");
	290	scm_request_requeue(scmrq);
	291	}
	292	return ret;
	293	}
	294
f30664e2 SO	295	static void scm_blk_request(struct request_queue *rq)
	296	{
	297	struct scm_device *scmdev = rq->queuedata;
	298	struct scm_blk_dev *bdev = dev_get_drvdata(&scmdev->dev);
bbc610a9	299	struct scm_request *scmrq = NULL;
f30664e2	300	struct request *req;
f30664e2 SO	301
f30664e2 SO	302	while ((req = blk_peek_request(rq))) {
bbc610a9 SO	303	if (!scm_permit_request(bdev, req))
	304	goto out;
	305
f30664e2	306	if (!scmrq) {
bbc610a9 SO	307	scmrq = scm_request_fetch();
	308	if (!scmrq) {
	309	SCM_LOG(5, "no request");
	310	goto out;
	311	}
	312	scm_request_init(bdev, scmrq);
f30664e2	313	}
bbc610a9 SO	314	scm_request_set(scmrq, req);
bbc610a9 SO	315
0d804b20 SO	316	if (!scm_reserve_cluster(scmrq)) {
0d804b20 SO	317	SCM_LOG(5, "cluster busy");
bbc610a9 SO	318	scm_request_set(scmrq, NULL);
	319	if (scmrq->aob->request.msb_count)
	320	goto out;
	321
0d804b20 SO	322	scm_request_done(scmrq);
	323	return;
	324	}
bbc610a9	325
0d804b20	326	if (scm_need_cluster_request(scmrq)) {
bbc610a9 SO	327	if (scmrq->aob->request.msb_count) {
	328	/* Start cluster requests separately. */
	329	scm_request_set(scmrq, NULL);
	330	if (scm_request_start(scmrq))
	331	return;
	332	} else {
	333	atomic_inc(&bdev->queued_reqs);
	334	blk_start_request(req);
	335	scm_initiate_cluster_request(scmrq);
	336	}
	337	scmrq = NULL;
	338	continue;
0d804b20	339	}
9d4df77f SO	340
9d4df77f SO	341	if (scm_request_prepare(scmrq)) {
bbc610a9 SO	342	SCM_LOG(5, "aidaw alloc failed");
	343	scm_request_set(scmrq, NULL);
	344	goto out;
9d4df77f	345	}
f30664e2 SO	346	blk_start_request(req);
f30664e2 SO	347
8622384f	348	if (scmrq->aob->request.msb_count < nr_requests_per_io)
bbc610a9 SO	349	continue;
	350
	351	if (scm_request_start(scmrq))
f30664e2	352	return;
bbc610a9 SO	353
bbc610a9 SO	354	scmrq = NULL;
f30664e2	355	}
bbc610a9 SO	356	out:
	357	if (scmrq)
	358	scm_request_start(scmrq);
	359	else
	360	scm_ensure_queue_restart(bdev);
f30664e2 SO	361	}
	362
	363	static void __scmrq_log_error(struct scm_request *scmrq)
	364	{
	365	struct aob *aob = scmrq->aob;
	366
	367	if (scmrq->error == -ETIMEDOUT)
	368	SCM_LOG(1, "Request timeout");
	369	else {
	370	SCM_LOG(1, "Request error");
	371	SCM_LOG_HEX(1, &aob->response, sizeof(aob->response));
	372	}
	373	if (scmrq->retries)
	374	SCM_LOG(1, "Retry request");
	375	else
	376	pr_err("An I/O operation to SCM failed with rc=%d\n",
	377	scmrq->error);
	378	}
	379
	380	void scm_blk_irq(struct scm_device scmdev, void data, int error)
	381	{
	382	struct scm_request *scmrq = data;
	383	struct scm_blk_dev *bdev = scmrq->bdev;
	384
	385	scmrq->error = error;
	386	if (error)
	387	__scmrq_log_error(scmrq);
	388
	389	spin_lock(&bdev->lock);
	390	list_add_tail(&scmrq->list, &bdev->finished_requests);
	391	spin_unlock(&bdev->lock);
	392	tasklet_hi_schedule(&bdev->tasklet);
	393	}
	394
4fa3c019 SO	395	static void scm_blk_handle_error(struct scm_request *scmrq)
	396	{
	397	struct scm_blk_dev *bdev = scmrq->bdev;
	398	unsigned long flags;
	399
	400	if (scmrq->error != -EIO)
	401	goto restart;
	402
	403	/* For -EIO the response block is valid. */
	404	switch (scmrq->aob->response.eqc) {
	405	case EQC_WR_PROHIBIT:
	406	spin_lock_irqsave(&bdev->lock, flags);
	407	if (bdev->state != SCM_WR_PROHIBIT)
3bff6038	408	pr_info("%lx: Write access to the SCM increment is suspended\n",
4fa3c019 SO	409	(unsigned long) bdev->scmdev->address);
	410	bdev->state = SCM_WR_PROHIBIT;
	411	spin_unlock_irqrestore(&bdev->lock, flags);
	412	goto requeue;
	413	default:
	414	break;
	415	}
	416
	417	restart:
605c3698	418	if (!eadm_start_aob(scmrq->aob))
4fa3c019 SO	419	return;
	420
	421	requeue:
	422	spin_lock_irqsave(&bdev->rq_lock, flags);
	423	scm_request_requeue(scmrq);
	424	spin_unlock_irqrestore(&bdev->rq_lock, flags);
	425	}
	426
f30664e2 SO	427	static void scm_blk_tasklet(struct scm_blk_dev *bdev)
	428	{
	429	struct scm_request *scmrq;
	430	unsigned long flags;
	431
	432	spin_lock_irqsave(&bdev->lock, flags);
	433	while (!list_empty(&bdev->finished_requests)) {
	434	scmrq = list_first_entry(&bdev->finished_requests,
	435	struct scm_request, list);
	436	list_del(&scmrq->list);
	437	spin_unlock_irqrestore(&bdev->lock, flags);
	438
	439	if (scmrq->error && scmrq->retries-- > 0) {
4fa3c019 SO	440	scm_blk_handle_error(scmrq);
4fa3c019 SO	441
f30664e2 SO	442	/* Request restarted or requeued, handle next. */
	443	spin_lock_irqsave(&bdev->lock, flags);
	444	continue;
	445	}
0d804b20 SO	446
	447	if (scm_test_cluster_request(scmrq)) {
	448	scm_cluster_request_irq(scmrq);
	449	spin_lock_irqsave(&bdev->lock, flags);
	450	continue;
	451	}
	452
f30664e2	453	scm_request_finish(scmrq);
f30664e2 SO	454	spin_lock_irqsave(&bdev->lock, flags);
	455	}
	456	spin_unlock_irqrestore(&bdev->lock, flags);
	457	/* Look out for more requests. */
	458	blk_run_queue(bdev->rq);
	459	}
	460
605c3698 SO	461	static const struct block_device_operations scm_blk_devops = {
	462	.owner = THIS_MODULE,
	463	};
	464
f30664e2 SO	465	int scm_blk_dev_setup(struct scm_blk_dev bdev, struct scm_device scmdev)
	466	{
	467	struct request_queue *rq;
	468	int len, ret = -ENOMEM;
	469	unsigned int devindex, nr_max_blk;
	470
	471	devindex = atomic_inc_return(&nr_devices) - 1;
	472	/* scma..scmz + scmaa..scmzz */
	473	if (devindex > 701) {
	474	ret = -ENODEV;
	475	goto out;
	476	}
	477
	478	bdev->scmdev = scmdev;
4fa3c019	479	bdev->state = SCM_OPER;
f30664e2 SO	480	spin_lock_init(&bdev->rq_lock);
	481	spin_lock_init(&bdev->lock);
	482	INIT_LIST_HEAD(&bdev->finished_requests);
	483	atomic_set(&bdev->queued_reqs, 0);
	484	tasklet_init(&bdev->tasklet,
	485	(void (*)(unsigned long)) scm_blk_tasklet,
	486	(unsigned long) bdev);
	487
	488	rq = blk_init_queue(scm_blk_request, &bdev->rq_lock);
	489	if (!rq)
	490	goto out;
	491
	492	bdev->rq = rq;
	493	nr_max_blk = min(scmdev->nr_max_block,
	494	(unsigned int) (PAGE_SIZE / sizeof(struct aidaw)));
	495
	496	blk_queue_logical_block_size(rq, 1 << 12);
	497	blk_queue_max_hw_sectors(rq, nr_max_blk << 3); /* 8 * 512 = blk_size */
	498	blk_queue_max_segments(rq, nr_max_blk);
	499	queue_flag_set_unlocked(QUEUE_FLAG_NONROT, rq);
b277da0a	500	queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, rq);
0d804b20	501	scm_blk_dev_cluster_setup(bdev);
f30664e2 SO	502
	503	bdev->gendisk = alloc_disk(SCM_NR_PARTS);
	504	if (!bdev->gendisk)
	505	goto out_queue;
	506
	507	rq->queuedata = scmdev;
f30664e2 SO	508	bdev->gendisk->private_data = scmdev;
	509	bdev->gendisk->fops = &scm_blk_devops;
	510	bdev->gendisk->queue = rq;
	511	bdev->gendisk->major = scm_major;
	512	bdev->gendisk->first_minor = devindex * SCM_NR_PARTS;
	513
	514	len = snprintf(bdev->gendisk->disk_name, DISK_NAME_LEN, "scm");
	515	if (devindex > 25) {
	516	len += snprintf(bdev->gendisk->disk_name + len,
	517	DISK_NAME_LEN - len, "%c",
	518	'a' + (devindex / 26) - 1);
	519	devindex = devindex % 26;
	520	}
	521	snprintf(bdev->gendisk->disk_name + len, DISK_NAME_LEN - len, "%c",
	522	'a' + devindex);
	523
	524	/* 512 byte sectors */
	525	set_capacity(bdev->gendisk, scmdev->size >> 9);
0d52c756	526	device_add_disk(&scmdev->dev, bdev->gendisk);
f30664e2 SO	527	return 0;
	528
	529	out_queue:
	530	blk_cleanup_queue(rq);
	531	out:
	532	atomic_dec(&nr_devices);
	533	return ret;
	534	}
	535
	536	void scm_blk_dev_cleanup(struct scm_blk_dev *bdev)
	537	{
	538	tasklet_kill(&bdev->tasklet);
	539	del_gendisk(bdev->gendisk);
	540	blk_cleanup_queue(bdev->gendisk->queue);
	541	put_disk(bdev->gendisk);
	542	}
	543
4fa3c019 SO	544	void scm_blk_set_available(struct scm_blk_dev *bdev)
	545	{
	546	unsigned long flags;
	547
	548	spin_lock_irqsave(&bdev->lock, flags);
	549	if (bdev->state == SCM_WR_PROHIBIT)
3bff6038	550	pr_info("%lx: Write access to the SCM increment is restored\n",
4fa3c019 SO	551	(unsigned long) bdev->scmdev->address);
	552	bdev->state = SCM_OPER;
	553	spin_unlock_irqrestore(&bdev->lock, flags);
	554	}
	555
8622384f SO	556	static bool __init scm_blk_params_valid(void)
	557	{
	558	if (!nr_requests_per_io \|\| nr_requests_per_io > 64)
	559	return false;
	560
	561	return scm_cluster_size_valid();
	562	}
	563
f30664e2 SO	564	static int __init scm_blk_init(void)
f30664e2 SO	565	{
0d804b20 SO	566	int ret = -EINVAL;
0d804b20 SO	567
8622384f	568	if (!scm_blk_params_valid())
0d804b20	569	goto out;
f30664e2 SO	570
	571	ret = register_blkdev(0, "scm");
	572	if (ret < 0)
	573	goto out;
	574
	575	scm_major = ret;
94f9852d WY	576	ret = scm_alloc_rqs(nr_requests);
94f9852d WY	577	if (ret)
fff60fab	578	goto out_free;
f30664e2 SO	579
f30664e2 SO	580	scm_debug = debug_register("scm_log", 16, 1, 16);
94f9852d WY	581	if (!scm_debug) {
94f9852d WY	582	ret = -ENOMEM;
f30664e2	583	goto out_free;
94f9852d	584	}
f30664e2 SO	585
	586	debug_register_view(scm_debug, &debug_hex_ascii_view);
	587	debug_set_level(scm_debug, 2);
	588
	589	ret = scm_drv_init();
	590	if (ret)
	591	goto out_dbf;
	592
	593	return ret;
	594
	595	out_dbf:
	596	debug_unregister(scm_debug);
	597	out_free:
	598	scm_free_rqs();
f30664e2 SO	599	unregister_blkdev(scm_major, "scm");
	600	out:
	601	return ret;
	602	}
	603	module_init(scm_blk_init);
	604
	605	static void __exit scm_blk_cleanup(void)
	606	{
	607	scm_drv_cleanup();
	608	debug_unregister(scm_debug);
	609	scm_free_rqs();
	610	unregister_blkdev(scm_major, "scm");
	611	}
	612	module_exit(scm_blk_cleanup);