blob: d0ab5019d885cea6113f677a4f58990fa4a3ca55 [file] [log] [blame]
/*
* 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/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 DEFINE_SPINLOCK(list_lock);
static LIST_HEAD(inactive_requests);
static unsigned int nr_requests = 64;
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_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);
free_page((unsigned long) scmrq->aidaw);
__scm_free_rq_cluster(scmrq);
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);
}
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->aidaw = (void *) get_zeroed_page(GFP_DMA);
scmrq->aob = (void *) get_zeroed_page(GFP_DMA);
if (!scmrq->aob || !scmrq->aidaw) {
__scm_free_rq(scmrq);
return -ENOMEM;
}
if (__scm_alloc_rq_cluster(scmrq)) {
__scm_free_rq(scmrq);
return -ENOMEM;
}
INIT_LIST_HEAD(&scmrq->list);
spin_lock_irq(&list_lock);
list_add(&scmrq->list, &inactive_requests);
spin_unlock_irq(&list_lock);
return 0;
}
static int scm_alloc_rqs(unsigned int nrqs)
{
int ret = 0;
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;
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 void scm_request_prepare(struct scm_request *scmrq)
{
struct scm_blk_dev *bdev = scmrq->bdev;
struct scm_device *scmdev = bdev->gendisk->private_data;
struct aidaw *aidaw = scmrq->aidaw;
struct msb *msb = &scmrq->aob->msb[0];
struct req_iterator iter;
struct bio_vec *bv;
msb->bs = MSB_BS_4K;
scmrq->aob->request.msb_count = 1;
msb->scm_addr = scmdev->address +
((u64) blk_rq_pos(scmrq->request) << 9);
msb->oc = (rq_data_dir(scmrq->request) == READ) ?
MSB_OC_READ : MSB_OC_WRITE;
msb->flags |= MSB_FLAG_IDA;
msb->data_addr = (u64) aidaw;
rq_for_each_segment(bv, scmrq->request, iter) {
WARN_ON(bv->bv_offset);
msb->blk_count += bv->bv_len >> 12;
aidaw->data_addr = (u64) page_address(bv->bv_page);
aidaw++;
}
}
static inline void scm_request_init(struct scm_blk_dev *bdev,
struct scm_request *scmrq,
struct request *req)
{
struct aob_rq_header *aobrq = to_aobrq(scmrq);
struct aob *aob = scmrq->aob;
memset(aob, 0, sizeof(*aob));
memset(scmrq->aidaw, 0, PAGE_SIZE);
aobrq->scmdev = bdev->scmdev;
aob->request.cmd_code = ARQB_CMD_MOVE;
aob->request.data = (u64) aobrq;
scmrq->request = req;
scmrq->bdev = bdev;
scmrq->retries = 4;
scmrq->error = 0;
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;
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);
}
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;
struct request *req;
int ret;
while ((req = blk_peek_request(rq))) {
if (req->cmd_type != REQ_TYPE_FS) {
blk_start_request(req);
blk_dump_rq_flags(req, KMSG_COMPONENT " bad request");
blk_end_request_all(req, -EIO);
continue;
}
if (!scm_permit_request(bdev, req)) {
scm_ensure_queue_restart(bdev);
return;
}
scmrq = scm_request_fetch();
if (!scmrq) {
SCM_LOG(5, "no request");
scm_ensure_queue_restart(bdev);
return;
}
scm_request_init(bdev, scmrq, req);
if (!scm_reserve_cluster(scmrq)) {
SCM_LOG(5, "cluster busy");
scm_request_done(scmrq);
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 = eadm_start_aob(scmrq->aob);
if (ret) {
SCM_LOG(5, "no subchannel");
scm_request_requeue(scmrq);
return;
}
}
}
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);
scm_blk_dev_cluster_setup(bdev);
bdev->gendisk = alloc_disk(SCM_NR_PARTS);
if (!bdev->gendisk)
goto out_queue;
rq->queuedata = scmdev;
bdev->gendisk->driverfs_dev = &scmdev->dev;
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);
add_disk(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 int __init scm_blk_init(void)
{
int ret = -EINVAL;
if (!scm_cluster_size_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);