![Sebastian Ott](/assets/img/avatar_default.png)
We increase the msb_count after we're finished building the request. That way we can always access the current request via scmrq->request[msb_count] . But once the request is started we need to make sure that the array index stays below msb_count. Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
256 lines
5.9 KiB
C
256 lines
5.9 KiB
C
/*
|
|
* 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 request *A, struct request *B)
|
|
{
|
|
unsigned long firstA, lastA, firstB, lastB;
|
|
|
|
firstA = ((u64) blk_rq_pos(A) << 9) / CLUSTER_SIZE;
|
|
lastA = (((u64) blk_rq_pos(A) << 9) +
|
|
blk_rq_bytes(A) - 1) / CLUSTER_SIZE;
|
|
|
|
firstB = ((u64) blk_rq_pos(B) << 9) / CLUSTER_SIZE;
|
|
lastB = (((u64) blk_rq_pos(B) << 9) +
|
|
blk_rq_bytes(B) - 1) / CLUSTER_SIZE;
|
|
|
|
return (firstB <= lastA && firstA <= lastB);
|
|
}
|
|
|
|
bool scm_reserve_cluster(struct scm_request *scmrq)
|
|
{
|
|
struct request *req = scmrq->request[scmrq->aob->request.msb_count];
|
|
struct scm_blk_dev *bdev = scmrq->bdev;
|
|
struct scm_request *iter;
|
|
int pos, add = 1;
|
|
|
|
if (write_cluster_size == 0)
|
|
return true;
|
|
|
|
spin_lock(&bdev->lock);
|
|
list_for_each_entry(iter, &bdev->cluster_list, cluster.list) {
|
|
if (iter == scmrq) {
|
|
/*
|
|
* We don't have to use clusters_intersect here, since
|
|
* cluster requests are always started separately.
|
|
*/
|
|
add = 0;
|
|
continue;
|
|
}
|
|
for (pos = 0; pos < iter->aob->request.msb_count; pos++) {
|
|
if (clusters_intersect(req, iter->request[pos]) &&
|
|
(rq_data_dir(req) == WRITE ||
|
|
rq_data_dir(iter->request[pos]) == WRITE)) {
|
|
spin_unlock(&bdev->lock);
|
|
return false;
|
|
}
|
|
}
|
|
}
|
|
if (add)
|
|
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[0];
|
|
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)
|
|
{
|
|
int pos = scmrq->aob->request.msb_count;
|
|
|
|
if (rq_data_dir(scmrq->request[pos]) == READ)
|
|
return false;
|
|
|
|
return blk_rq_bytes(scmrq->request[pos]) < 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));
|
|
}
|