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