Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 0d804b20 authored by Sebastian Ott's avatar Sebastian Ott Committed by Martin Schwidefsky
Browse files

s390/scm_block: force cluster writes 



Force writes to Storage Class Memory (SCM) to be in done in clusters.

Signed-off-by: default avatarSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent f30664e2

drivers/s390/block/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -81,3 +81,10 @@ config SCM_BLOCK 


	  To compile this driver as a module, choose M here: the

	  module will be called scm_block.



config SCM_BLOCK_CLUSTER_WRITE

	def_bool y

	prompt "SCM force cluster writes"

	depends on SCM_BLOCK

	help

	  Force writes to Storage Class Memory (SCM) to be in done in clusters.

drivers/s390/block/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -19,4 +19,7 @@ obj-$(CONFIG_BLK_DEV_XPRAM) += xpram.o 
obj-$(CONFIG_DCSSBLK) += dcssblk.o



scm_block-objs := scm_drv.o scm_blk.o

ifdef CONFIG_SCM_BLOCK_CLUSTER_WRITE

scm_block-objs += scm_blk_cluster.o

endif

obj-$(CONFIG_SCM_BLOCK) += scm_block.o

drivers/s390/block/scm_blk.c

+34 −3
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ static void __scm_free_rq(struct scm_request *scmrq) 


	free_page((unsigned long) scmrq->aob);

	free_page((unsigned long) scmrq->aidaw);

	__scm_free_rq_cluster(scmrq);

	kfree(aobrq);

}
@@ -70,6 +71,12 @@ static int __scm_alloc_rq(void) 
		__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);
@@ -170,6 +177,7 @@ static inline void scm_request_init(struct scm_blk_dev *bdev, 
	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)
@@ -181,17 +189,19 @@ static void scm_ensure_queue_restart(struct scm_blk_dev *bdev) 
	blk_delay_queue(bdev->rq, SCM_QUEUE_DELAY);

}



static void scm_request_requeue(struct scm_request *scmrq)

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);

	scm_request_done(scmrq);

	scm_ensure_queue_restart(bdev);

}



static void scm_request_finish(struct scm_request *scmrq)

void scm_request_finish(struct scm_request *scmrq)

{

	scm_release_cluster(scmrq);

	blk_end_request_all(scmrq->request, scmrq->error);

	scm_request_done(scmrq);

}
@@ -215,6 +225,16 @@ static void scm_blk_request(struct request_queue *rq) 
			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)) {

			blk_start_request(req);

			scm_initiate_cluster_request(scmrq);

			return;

		}

		scm_request_prepare(scmrq);

		blk_start_request(req);
@@ -282,6 +302,13 @@ static void scm_blk_tasklet(struct scm_blk_dev *bdev) 
			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);

		atomic_dec(&bdev->queued_reqs);

		spin_lock_irqsave(&bdev->lock, flags);
@@ -325,6 +352,7 @@ int scm_blk_dev_setup(struct scm_blk_dev *bdev, struct scm_device *scmdev) 
	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)
@@ -370,7 +398,10 @@ void scm_blk_dev_cleanup(struct scm_blk_dev *bdev) 


static int __init scm_blk_init(void)

{

	int ret;

	int ret = -EINVAL;



	if (!scm_cluster_size_valid())

		goto out;



	ret = register_blkdev(0, "scm");

	if (ret < 0)

drivers/s390/block/scm_blk.h

+38 −0
Original line number Diff line number Diff line
@@ -22,6 +22,9 @@ struct scm_blk_dev { 
	spinlock_t lock;	/* guard the rest of the blockdev */

	atomic_t queued_reqs;

	struct list_head finished_requests;

#ifdef CONFIG_SCM_BLOCK_CLUSTER_WRITE

	struct list_head cluster_list;

#endif

};



struct scm_request {
@@ -32,6 +35,13 @@ struct scm_request { 
	struct list_head list;

	u8 retries;

	int error;

#ifdef CONFIG_SCM_BLOCK_CLUSTER_WRITE

	struct {

		enum {CLUSTER_NONE, CLUSTER_READ, CLUSTER_WRITE} state;

		struct list_head list;

		void **buf;

	} cluster;

#endif

};



#define to_aobrq(rq) container_of((void *) rq, struct aob_rq_header, data)
@@ -40,9 +50,37 @@ int scm_blk_dev_setup(struct scm_blk_dev *, struct scm_device *); 
void scm_blk_dev_cleanup(struct scm_blk_dev *);

void scm_blk_irq(struct scm_device *, void *, int);



void scm_request_finish(struct scm_request *);

void scm_request_requeue(struct scm_request *);



int scm_drv_init(void);

void scm_drv_cleanup(void);



#ifdef CONFIG_SCM_BLOCK_CLUSTER_WRITE

void __scm_free_rq_cluster(struct scm_request *);

int __scm_alloc_rq_cluster(struct scm_request *);

void scm_request_cluster_init(struct scm_request *);

bool scm_reserve_cluster(struct scm_request *);

void scm_release_cluster(struct scm_request *);

void scm_blk_dev_cluster_setup(struct scm_blk_dev *);

bool scm_need_cluster_request(struct scm_request *);

void scm_initiate_cluster_request(struct scm_request *);

void scm_cluster_request_irq(struct scm_request *);

bool scm_test_cluster_request(struct scm_request *);

bool scm_cluster_size_valid(void);

#else

#define __scm_free_rq_cluster(scmrq) {}

#define __scm_alloc_rq_cluster(scmrq) 0

#define scm_request_cluster_init(scmrq) {}

#define scm_reserve_cluster(scmrq) true

#define scm_release_cluster(scmrq) {}

#define scm_blk_dev_cluster_setup(bdev) {}

#define scm_need_cluster_request(scmrq) false

#define scm_initiate_cluster_request(scmrq) {}

#define scm_cluster_request_irq(scmrq) {}

#define scm_test_cluster_request(scmrq) false

#define scm_cluster_size_valid() true

#endif



extern debug_info_t *scm_debug;

drivers/s390/block/scm_blk_cluster.c

0 → 100644
+228 −0
Original line number Diff line number Diff line 
/*

 * 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 void 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 aidaw *aidaw = scmrq->aidaw;

	struct msb *msb = &scmrq->aob->msb[0];

	struct req_iterator iter;

	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:

		scmrq->aob->request.msb_count = 1;

		msb->bs = MSB_BS_4K;

		msb->oc = MSB_OC_READ;

		msb->flags = MSB_FLAG_IDA;

		msb->data_addr = (u64) aidaw;

		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;



		for (i = 0; i < msb->blk_count; i++) {

			aidaw->data_addr = (u64) scmrq->cluster.buf[i];

			aidaw++;

		}



		break;

	case CLUSTER_WRITE:

		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;

	}

}



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)

{

	scm_prepare_cluster_request(scmrq);

	if (scm_start_aob(scmrq->aob))

		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)

{

	return write_cluster_size == 0 || write_cluster_size == 32 ||

		write_cluster_size == 64 || write_cluster_size == 128;

}