From 0d804b20735d974534abb422f723d404b779433a Mon Sep 17 00:00:00 2001 From: Sebastian Ott Date: Tue, 28 Aug 2012 16:51:19 +0200 Subject: s390/scm_block: force cluster writes Force writes to Storage Class Memory (SCM) to be in done in clusters. Signed-off-by: Sebastian Ott Signed-off-by: Martin Schwidefsky --- drivers/s390/block/scm_blk_cluster.c | 228 +++++++++++++++++++++++++++++++++++ 1 file changed, 228 insertions(+) create mode 100644 drivers/s390/block/scm_blk_cluster.c (limited to 'drivers/s390/block/scm_blk_cluster.c') diff --git a/drivers/s390/block/scm_blk_cluster.c b/drivers/s390/block/scm_blk_cluster.c new file mode 100644 index 0000000..f4bb61b --- /dev/null +++ b/drivers/s390/block/scm_blk_cluster.c @@ -0,0 +1,228 @@ +/* + * Block driver for s390 storage class memory. + * + * Copyright IBM Corp. 2012 + * Author(s): Sebastian Ott + */ + +#include +#include +#include +#include +#include +#include +#include +#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; +} -- cgit v1.1