2 * Block driver for s390 storage class memory.
4 * Copyright IBM Corp. 2012
5 * Author(s): Sebastian Ott <sebott@linux.vnet.ibm.com>
8 #include <linux/spinlock.h>
9 #include <linux/module.h>
10 #include <linux/blkdev.h>
11 #include <linux/genhd.h>
12 #include <linux/slab.h>
13 #include <linux/list.h>
17 static unsigned int write_cluster_size = 64;
18 module_param(write_cluster_size, uint, S_IRUGO);
19 MODULE_PARM_DESC(write_cluster_size,
20 "Number of pages used for contiguous writes.");
22 #define CLUSTER_SIZE (write_cluster_size * PAGE_SIZE)
24 void __scm_free_rq_cluster(struct scm_request *scmrq)
28 if (!scmrq->cluster.buf)
31 for (i = 0; i < 2 * write_cluster_size; i++)
32 free_page((unsigned long) scmrq->cluster.buf[i]);
34 kfree(scmrq->cluster.buf);
37 int __scm_alloc_rq_cluster(struct scm_request *scmrq)
41 scmrq->cluster.buf = kzalloc(sizeof(void *) * 2 * write_cluster_size,
43 if (!scmrq->cluster.buf)
46 for (i = 0; i < 2 * write_cluster_size; i++) {
47 scmrq->cluster.buf[i] = (void *) get_zeroed_page(GFP_DMA);
48 if (!scmrq->cluster.buf[i])
51 INIT_LIST_HEAD(&scmrq->cluster.list);
55 void scm_request_cluster_init(struct scm_request *scmrq)
57 scmrq->cluster.state = CLUSTER_NONE;
60 static bool clusters_intersect(struct scm_request *A, struct scm_request *B)
62 unsigned long firstA, lastA, firstB, lastB;
64 firstA = ((u64) blk_rq_pos(A->request) << 9) / CLUSTER_SIZE;
65 lastA = (((u64) blk_rq_pos(A->request) << 9) +
66 blk_rq_bytes(A->request) - 1) / CLUSTER_SIZE;
68 firstB = ((u64) blk_rq_pos(B->request) << 9) / CLUSTER_SIZE;
69 lastB = (((u64) blk_rq_pos(B->request) << 9) +
70 blk_rq_bytes(B->request) - 1) / CLUSTER_SIZE;
72 return (firstB <= lastA && firstA <= lastB);
75 bool scm_reserve_cluster(struct scm_request *scmrq)
77 struct scm_blk_dev *bdev = scmrq->bdev;
78 struct scm_request *iter;
80 if (write_cluster_size == 0)
83 spin_lock(&bdev->lock);
84 list_for_each_entry(iter, &bdev->cluster_list, cluster.list) {
85 if (clusters_intersect(scmrq, iter) &&
86 (rq_data_dir(scmrq->request) == WRITE ||
87 rq_data_dir(iter->request) == WRITE)) {
88 spin_unlock(&bdev->lock);
92 list_add(&scmrq->cluster.list, &bdev->cluster_list);
93 spin_unlock(&bdev->lock);
98 void scm_release_cluster(struct scm_request *scmrq)
100 struct scm_blk_dev *bdev = scmrq->bdev;
103 if (write_cluster_size == 0)
106 spin_lock_irqsave(&bdev->lock, flags);
107 list_del(&scmrq->cluster.list);
108 spin_unlock_irqrestore(&bdev->lock, flags);
111 void scm_blk_dev_cluster_setup(struct scm_blk_dev *bdev)
113 INIT_LIST_HEAD(&bdev->cluster_list);
114 blk_queue_io_opt(bdev->rq, CLUSTER_SIZE);
117 static void scm_prepare_cluster_request(struct scm_request *scmrq)
119 struct scm_blk_dev *bdev = scmrq->bdev;
120 struct scm_device *scmdev = bdev->gendisk->private_data;
121 struct request *req = scmrq->request;
122 struct aidaw *aidaw = scmrq->aidaw;
123 struct msb *msb = &scmrq->aob->msb[0];
124 struct req_iterator iter;
129 switch (scmrq->cluster.state) {
131 scmrq->cluster.state = CLUSTER_READ;
134 scmrq->aob->request.msb_count = 1;
136 msb->oc = MSB_OC_READ;
137 msb->flags = MSB_FLAG_IDA;
138 msb->data_addr = (u64) aidaw;
139 msb->blk_count = write_cluster_size;
141 addr = scmdev->address + ((u64) blk_rq_pos(req) << 9);
142 msb->scm_addr = round_down(addr, CLUSTER_SIZE);
145 round_down(addr + (u64) blk_rq_bytes(req) - 1,
147 msb->blk_count = 2 * write_cluster_size;
149 for (i = 0; i < msb->blk_count; i++) {
150 aidaw->data_addr = (u64) scmrq->cluster.buf[i];
156 msb->oc = MSB_OC_WRITE;
158 for (addr = msb->scm_addr;
159 addr < scmdev->address + ((u64) blk_rq_pos(req) << 9);
161 aidaw->data_addr = (u64) scmrq->cluster.buf[i];
165 rq_for_each_segment(bv, req, iter) {
166 aidaw->data_addr = (u64) page_address(bv->bv_page);
170 for (; i < msb->blk_count; i++) {
171 aidaw->data_addr = (u64) scmrq->cluster.buf[i];
178 bool scm_need_cluster_request(struct scm_request *scmrq)
180 if (rq_data_dir(scmrq->request) == READ)
183 return blk_rq_bytes(scmrq->request) < CLUSTER_SIZE;
186 /* Called with queue lock held. */
187 void scm_initiate_cluster_request(struct scm_request *scmrq)
189 scm_prepare_cluster_request(scmrq);
190 if (scm_start_aob(scmrq->aob))
191 scm_request_requeue(scmrq);
194 bool scm_test_cluster_request(struct scm_request *scmrq)
196 return scmrq->cluster.state != CLUSTER_NONE;
199 void scm_cluster_request_irq(struct scm_request *scmrq)
201 struct scm_blk_dev *bdev = scmrq->bdev;
204 switch (scmrq->cluster.state) {
210 scm_request_finish(scmrq);
213 scmrq->cluster.state = CLUSTER_WRITE;
214 spin_lock_irqsave(&bdev->rq_lock, flags);
215 scm_initiate_cluster_request(scmrq);
216 spin_unlock_irqrestore(&bdev->rq_lock, flags);
219 scm_request_finish(scmrq);
224 bool scm_cluster_size_valid(void)
226 return write_cluster_size == 0 || write_cluster_size == 32 ||
227 write_cluster_size == 64 || write_cluster_size == 128;