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/*
* Block driver for s390 storage class memory.
*
* Copyright IBM Corp. 2012
* Author(s): Sebastian Ott <sebott@linux.vnet.ibm.com>
*/
#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"
static unsigned int write_cluster_size = 64;
module_param(write_cluster_size, uint, S_IRUGO);
MODULE_PARM_DESC(write_cluster_size,
"Number of pages used for contiguous writes.");
#define CLUSTER_SIZE (write_cluster_size * PAGE_SIZE)
void __scm_free_rq_cluster(struct scm_request *scmrq)
{
int i;
if (!scmrq->cluster.buf)
return;
for (i = 0; i < 2 * write_cluster_size; i++)
free_page((unsigned long) scmrq->cluster.buf[i]);
kfree(scmrq->cluster.buf);
}
int __scm_alloc_rq_cluster(struct scm_request *scmrq)
{
int i;
scmrq->cluster.buf = kzalloc(sizeof(void *) * 2 * write_cluster_size,
GFP_KERNEL);
if (!scmrq->cluster.buf)
return -ENOMEM;
for (i = 0; i < 2 * write_cluster_size; i++) {
scmrq->cluster.buf[i] = (void *) get_zeroed_page(GFP_DMA);
if (!scmrq->cluster.buf[i])
return -ENOMEM;
}
INIT_LIST_HEAD(&scmrq->cluster.list);
return 0;
}
void scm_request_cluster_init(struct scm_request *scmrq)
{
scmrq->cluster.state = CLUSTER_NONE;
}
static bool clusters_intersect(struct scm_request *A, struct scm_request *B)
{
unsigned long firstA, lastA, firstB, lastB;
firstA = ((u64) blk_rq_pos(A->request) << 9) / CLUSTER_SIZE;
lastA = (((u64) blk_rq_pos(A->request) << 9) +
blk_rq_bytes(A->request) - 1) / CLUSTER_SIZE;
firstB = ((u64) blk_rq_pos(B->request) << 9) / CLUSTER_SIZE;
lastB = (((u64) blk_rq_pos(B->request) << 9) +
blk_rq_bytes(B->request) - 1) / CLUSTER_SIZE;
return (firstB <= lastA && firstA <= lastB);
}
bool scm_reserve_cluster(struct scm_request *scmrq)
{
struct scm_blk_dev *bdev = scmrq->bdev;
struct scm_request *iter;
if (write_cluster_size == 0)
return true;
spin_lock(&bdev->lock);
list_for_each_entry(iter, &bdev->cluster_list, cluster.list) {
if (clusters_intersect(scmrq, iter) &&
(rq_data_dir(scmrq->request) == WRITE ||
rq_data_dir(iter->request) == WRITE)) {
spin_unlock(&bdev->lock);
return false;
}
}
list_add(&scmrq->cluster.list, &bdev->cluster_list);
spin_unlock(&bdev->lock);
return true;
}
void scm_release_cluster(struct scm_request *scmrq)
{
struct scm_blk_dev *bdev = scmrq->bdev;
unsigned long flags;
if (write_cluster_size == 0)
return;
spin_lock_irqsave(&bdev->lock, flags);
list_del(&scmrq->cluster.list);
spin_unlock_irqrestore(&bdev->lock, flags);
}
void scm_blk_dev_cluster_setup(struct scm_blk_dev *bdev)
{
INIT_LIST_HEAD(&bdev->cluster_list);
blk_queue_io_opt(bdev->rq, CLUSTER_SIZE);
}
static int scm_prepare_cluster_request(struct scm_request *scmrq)
{
struct scm_blk_dev *bdev = scmrq->bdev;
struct scm_device *scmdev = bdev->gendisk->private_data;
struct request *req = scmrq->request;
struct msb *msb = &scmrq->aob->msb[0];
struct req_iterator iter;
struct aidaw *aidaw;
struct bio_vec bv;
int i = 0;
u64 addr;
switch (scmrq->cluster.state) {
case CLUSTER_NONE:
scmrq->cluster.state = CLUSTER_READ;
/* fall through */
case CLUSTER_READ:
msb->bs = MSB_BS_4K;
msb->oc = MSB_OC_READ;
msb->flags = MSB_FLAG_IDA;
msb->blk_count = write_cluster_size;
addr = scmdev->address + ((u64) blk_rq_pos(req) << 9);
msb->scm_addr = round_down(addr, CLUSTER_SIZE);
if (msb->scm_addr !=
round_down(addr + (u64) blk_rq_bytes(req) - 1,
CLUSTER_SIZE))
msb->blk_count = 2 * write_cluster_size;
aidaw = scm_aidaw_fetch(scmrq, msb->blk_count * PAGE_SIZE);
if (!aidaw)
return -ENOMEM;
scmrq->aob->request.msb_count = 1;
msb->data_addr = (u64) aidaw;
for (i = 0; i < msb->blk_count; i++) {
aidaw->data_addr = (u64) scmrq->cluster.buf[i];
aidaw++;
}
break;
case CLUSTER_WRITE:
aidaw = (void *) msb->data_addr;
msb->oc = MSB_OC_WRITE;
for (addr = msb->scm_addr;
addr < scmdev->address + ((u64) blk_rq_pos(req) << 9);
addr += PAGE_SIZE) {
aidaw->data_addr = (u64) scmrq->cluster.buf[i];
aidaw++;
i++;
}
rq_for_each_segment(bv, req, iter) {
aidaw->data_addr = (u64) page_address(bv.bv_page);
aidaw++;
i++;
}
for (; i < msb->blk_count; i++) {
aidaw->data_addr = (u64) scmrq->cluster.buf[i];
aidaw++;
}
break;
}
return 0;
}
bool scm_need_cluster_request(struct scm_request *scmrq)
{
if (rq_data_dir(scmrq->request) == READ)
return false;
return blk_rq_bytes(scmrq->request) < CLUSTER_SIZE;
}
/* Called with queue lock held. */
void scm_initiate_cluster_request(struct scm_request *scmrq)
{
if (scm_prepare_cluster_request(scmrq))
goto requeue;
if (eadm_start_aob(scmrq->aob))
goto requeue;
return;
requeue:
scm_request_requeue(scmrq);
}
bool scm_test_cluster_request(struct scm_request *scmrq)
{
return scmrq->cluster.state != CLUSTER_NONE;
}
void scm_cluster_request_irq(struct scm_request *scmrq)
{
struct scm_blk_dev *bdev = scmrq->bdev;
unsigned long flags;
switch (scmrq->cluster.state) {
case CLUSTER_NONE:
BUG();
break;
case CLUSTER_READ:
if (scmrq->error) {
scm_request_finish(scmrq);
break;
}
scmrq->cluster.state = CLUSTER_WRITE;
spin_lock_irqsave(&bdev->rq_lock, flags);
scm_initiate_cluster_request(scmrq);
spin_unlock_irqrestore(&bdev->rq_lock, flags);
break;
case CLUSTER_WRITE:
scm_request_finish(scmrq);
break;
}
}
bool scm_cluster_size_valid(void)
{
if (write_cluster_size == 1 || write_cluster_size > 128)
return false;
return !(write_cluster_size & (write_cluster_size - 1));
}
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