--- /dev/null
+/*
+ * 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));
+}
Code Review / kvmfornfv.git / blobdiff