![Al Viro](/assets/img/avatar_default.png)
The value passed is 0 in all but "it can never happen" cases (and those only in a couple of drivers) *and* it would've been lost on the way out anyway, even if something tried to pass something meaningful. Just don't bother. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
502 lines
12 KiB
C
502 lines
12 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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#define KMSG_COMPONENT "scm_block"
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#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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#include <linux/interrupt.h>
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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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debug_info_t *scm_debug;
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static int scm_major;
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static DEFINE_SPINLOCK(list_lock);
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static LIST_HEAD(inactive_requests);
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static unsigned int nr_requests = 64;
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static atomic_t nr_devices = ATOMIC_INIT(0);
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module_param(nr_requests, uint, S_IRUGO);
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MODULE_PARM_DESC(nr_requests, "Number of parallel requests.");
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MODULE_DESCRIPTION("Block driver for s390 storage class memory.");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("scm:scmdev*");
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static void __scm_free_rq(struct scm_request *scmrq)
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{
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struct aob_rq_header *aobrq = to_aobrq(scmrq);
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free_page((unsigned long) scmrq->aob);
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free_page((unsigned long) scmrq->aidaw);
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__scm_free_rq_cluster(scmrq);
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kfree(aobrq);
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}
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static void scm_free_rqs(void)
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{
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struct list_head *iter, *safe;
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struct scm_request *scmrq;
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spin_lock_irq(&list_lock);
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list_for_each_safe(iter, safe, &inactive_requests) {
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scmrq = list_entry(iter, struct scm_request, list);
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list_del(&scmrq->list);
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__scm_free_rq(scmrq);
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}
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spin_unlock_irq(&list_lock);
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}
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static int __scm_alloc_rq(void)
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{
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struct aob_rq_header *aobrq;
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struct scm_request *scmrq;
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aobrq = kzalloc(sizeof(*aobrq) + sizeof(*scmrq), GFP_KERNEL);
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if (!aobrq)
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return -ENOMEM;
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scmrq = (void *) aobrq->data;
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scmrq->aidaw = (void *) get_zeroed_page(GFP_DMA);
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scmrq->aob = (void *) get_zeroed_page(GFP_DMA);
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if (!scmrq->aob || !scmrq->aidaw) {
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__scm_free_rq(scmrq);
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return -ENOMEM;
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}
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if (__scm_alloc_rq_cluster(scmrq)) {
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__scm_free_rq(scmrq);
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return -ENOMEM;
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}
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INIT_LIST_HEAD(&scmrq->list);
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spin_lock_irq(&list_lock);
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list_add(&scmrq->list, &inactive_requests);
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spin_unlock_irq(&list_lock);
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return 0;
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}
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static int scm_alloc_rqs(unsigned int nrqs)
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{
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int ret = 0;
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while (nrqs-- && !ret)
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ret = __scm_alloc_rq();
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return ret;
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}
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static struct scm_request *scm_request_fetch(void)
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{
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struct scm_request *scmrq = NULL;
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spin_lock(&list_lock);
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if (list_empty(&inactive_requests))
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goto out;
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scmrq = list_first_entry(&inactive_requests, struct scm_request, list);
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list_del(&scmrq->list);
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out:
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spin_unlock(&list_lock);
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return scmrq;
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}
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static void scm_request_done(struct scm_request *scmrq)
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{
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unsigned long flags;
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spin_lock_irqsave(&list_lock, flags);
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list_add(&scmrq->list, &inactive_requests);
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spin_unlock_irqrestore(&list_lock, flags);
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}
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static int scm_open(struct block_device *blkdev, fmode_t mode)
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{
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return scm_get_ref();
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}
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static void scm_release(struct gendisk *gendisk, fmode_t mode)
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{
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scm_put_ref();
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}
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static const struct block_device_operations scm_blk_devops = {
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.owner = THIS_MODULE,
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.open = scm_open,
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.release = scm_release,
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};
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static bool scm_permit_request(struct scm_blk_dev *bdev, struct request *req)
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{
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return rq_data_dir(req) != WRITE || bdev->state != SCM_WR_PROHIBIT;
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}
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static void scm_request_prepare(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 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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msb->bs = MSB_BS_4K;
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scmrq->aob->request.msb_count = 1;
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msb->scm_addr = scmdev->address +
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((u64) blk_rq_pos(scmrq->request) << 9);
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msb->oc = (rq_data_dir(scmrq->request) == READ) ?
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MSB_OC_READ : MSB_OC_WRITE;
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msb->flags |= MSB_FLAG_IDA;
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msb->data_addr = (u64) aidaw;
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rq_for_each_segment(bv, scmrq->request, iter) {
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WARN_ON(bv->bv_offset);
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msb->blk_count += bv->bv_len >> 12;
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aidaw->data_addr = (u64) page_address(bv->bv_page);
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aidaw++;
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}
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}
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static inline void scm_request_init(struct scm_blk_dev *bdev,
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struct scm_request *scmrq,
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struct request *req)
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{
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struct aob_rq_header *aobrq = to_aobrq(scmrq);
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struct aob *aob = scmrq->aob;
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memset(aob, 0, sizeof(*aob));
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memset(scmrq->aidaw, 0, PAGE_SIZE);
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aobrq->scmdev = bdev->scmdev;
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aob->request.cmd_code = ARQB_CMD_MOVE;
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aob->request.data = (u64) aobrq;
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scmrq->request = req;
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scmrq->bdev = bdev;
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scmrq->retries = 4;
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scmrq->error = 0;
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scm_request_cluster_init(scmrq);
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}
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static void scm_ensure_queue_restart(struct scm_blk_dev *bdev)
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{
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if (atomic_read(&bdev->queued_reqs)) {
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/* Queue restart is triggered by the next interrupt. */
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return;
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}
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blk_delay_queue(bdev->rq, SCM_QUEUE_DELAY);
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}
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void scm_request_requeue(struct scm_request *scmrq)
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{
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struct scm_blk_dev *bdev = scmrq->bdev;
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scm_release_cluster(scmrq);
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blk_requeue_request(bdev->rq, scmrq->request);
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atomic_dec(&bdev->queued_reqs);
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scm_request_done(scmrq);
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scm_ensure_queue_restart(bdev);
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}
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void scm_request_finish(struct scm_request *scmrq)
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{
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struct scm_blk_dev *bdev = scmrq->bdev;
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scm_release_cluster(scmrq);
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blk_end_request_all(scmrq->request, scmrq->error);
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atomic_dec(&bdev->queued_reqs);
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scm_request_done(scmrq);
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}
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static void scm_blk_request(struct request_queue *rq)
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{
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struct scm_device *scmdev = rq->queuedata;
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struct scm_blk_dev *bdev = dev_get_drvdata(&scmdev->dev);
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struct scm_request *scmrq;
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struct request *req;
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int ret;
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while ((req = blk_peek_request(rq))) {
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if (req->cmd_type != REQ_TYPE_FS)
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continue;
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if (!scm_permit_request(bdev, req)) {
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scm_ensure_queue_restart(bdev);
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return;
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}
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scmrq = scm_request_fetch();
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if (!scmrq) {
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SCM_LOG(5, "no request");
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scm_ensure_queue_restart(bdev);
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return;
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}
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scm_request_init(bdev, scmrq, req);
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if (!scm_reserve_cluster(scmrq)) {
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SCM_LOG(5, "cluster busy");
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scm_request_done(scmrq);
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return;
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}
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if (scm_need_cluster_request(scmrq)) {
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atomic_inc(&bdev->queued_reqs);
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blk_start_request(req);
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scm_initiate_cluster_request(scmrq);
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return;
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}
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scm_request_prepare(scmrq);
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atomic_inc(&bdev->queued_reqs);
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blk_start_request(req);
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ret = scm_start_aob(scmrq->aob);
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if (ret) {
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SCM_LOG(5, "no subchannel");
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scm_request_requeue(scmrq);
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return;
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}
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}
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}
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static void __scmrq_log_error(struct scm_request *scmrq)
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{
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struct aob *aob = scmrq->aob;
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if (scmrq->error == -ETIMEDOUT)
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SCM_LOG(1, "Request timeout");
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else {
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SCM_LOG(1, "Request error");
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SCM_LOG_HEX(1, &aob->response, sizeof(aob->response));
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}
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if (scmrq->retries)
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SCM_LOG(1, "Retry request");
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else
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pr_err("An I/O operation to SCM failed with rc=%d\n",
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scmrq->error);
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}
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void scm_blk_irq(struct scm_device *scmdev, void *data, int error)
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{
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struct scm_request *scmrq = data;
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struct scm_blk_dev *bdev = scmrq->bdev;
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scmrq->error = error;
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if (error)
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__scmrq_log_error(scmrq);
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spin_lock(&bdev->lock);
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list_add_tail(&scmrq->list, &bdev->finished_requests);
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spin_unlock(&bdev->lock);
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tasklet_hi_schedule(&bdev->tasklet);
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}
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static void scm_blk_handle_error(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 (scmrq->error != -EIO)
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goto restart;
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/* For -EIO the response block is valid. */
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switch (scmrq->aob->response.eqc) {
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case EQC_WR_PROHIBIT:
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spin_lock_irqsave(&bdev->lock, flags);
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if (bdev->state != SCM_WR_PROHIBIT)
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pr_info("%lx: Write access to the SCM increment is suspended\n",
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(unsigned long) bdev->scmdev->address);
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bdev->state = SCM_WR_PROHIBIT;
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spin_unlock_irqrestore(&bdev->lock, flags);
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goto requeue;
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default:
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break;
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}
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restart:
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if (!scm_start_aob(scmrq->aob))
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return;
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requeue:
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spin_lock_irqsave(&bdev->rq_lock, flags);
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scm_request_requeue(scmrq);
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spin_unlock_irqrestore(&bdev->rq_lock, flags);
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}
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static void scm_blk_tasklet(struct scm_blk_dev *bdev)
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{
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struct scm_request *scmrq;
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unsigned long flags;
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spin_lock_irqsave(&bdev->lock, flags);
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while (!list_empty(&bdev->finished_requests)) {
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scmrq = list_first_entry(&bdev->finished_requests,
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struct scm_request, list);
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list_del(&scmrq->list);
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spin_unlock_irqrestore(&bdev->lock, flags);
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if (scmrq->error && scmrq->retries-- > 0) {
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scm_blk_handle_error(scmrq);
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/* Request restarted or requeued, handle next. */
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spin_lock_irqsave(&bdev->lock, flags);
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continue;
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}
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if (scm_test_cluster_request(scmrq)) {
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scm_cluster_request_irq(scmrq);
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spin_lock_irqsave(&bdev->lock, flags);
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continue;
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}
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scm_request_finish(scmrq);
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spin_lock_irqsave(&bdev->lock, flags);
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}
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spin_unlock_irqrestore(&bdev->lock, flags);
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/* Look out for more requests. */
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blk_run_queue(bdev->rq);
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}
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int scm_blk_dev_setup(struct scm_blk_dev *bdev, struct scm_device *scmdev)
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{
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struct request_queue *rq;
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int len, ret = -ENOMEM;
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unsigned int devindex, nr_max_blk;
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devindex = atomic_inc_return(&nr_devices) - 1;
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/* scma..scmz + scmaa..scmzz */
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if (devindex > 701) {
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ret = -ENODEV;
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goto out;
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}
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bdev->scmdev = scmdev;
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bdev->state = SCM_OPER;
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spin_lock_init(&bdev->rq_lock);
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spin_lock_init(&bdev->lock);
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INIT_LIST_HEAD(&bdev->finished_requests);
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atomic_set(&bdev->queued_reqs, 0);
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tasklet_init(&bdev->tasklet,
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(void (*)(unsigned long)) scm_blk_tasklet,
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(unsigned long) bdev);
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rq = blk_init_queue(scm_blk_request, &bdev->rq_lock);
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if (!rq)
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goto out;
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bdev->rq = rq;
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nr_max_blk = min(scmdev->nr_max_block,
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(unsigned int) (PAGE_SIZE / sizeof(struct aidaw)));
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blk_queue_logical_block_size(rq, 1 << 12);
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blk_queue_max_hw_sectors(rq, nr_max_blk << 3); /* 8 * 512 = blk_size */
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blk_queue_max_segments(rq, nr_max_blk);
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queue_flag_set_unlocked(QUEUE_FLAG_NONROT, rq);
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scm_blk_dev_cluster_setup(bdev);
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bdev->gendisk = alloc_disk(SCM_NR_PARTS);
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if (!bdev->gendisk)
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goto out_queue;
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rq->queuedata = scmdev;
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bdev->gendisk->driverfs_dev = &scmdev->dev;
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bdev->gendisk->private_data = scmdev;
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bdev->gendisk->fops = &scm_blk_devops;
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bdev->gendisk->queue = rq;
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bdev->gendisk->major = scm_major;
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bdev->gendisk->first_minor = devindex * SCM_NR_PARTS;
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len = snprintf(bdev->gendisk->disk_name, DISK_NAME_LEN, "scm");
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if (devindex > 25) {
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len += snprintf(bdev->gendisk->disk_name + len,
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DISK_NAME_LEN - len, "%c",
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'a' + (devindex / 26) - 1);
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devindex = devindex % 26;
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}
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snprintf(bdev->gendisk->disk_name + len, DISK_NAME_LEN - len, "%c",
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'a' + devindex);
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/* 512 byte sectors */
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set_capacity(bdev->gendisk, scmdev->size >> 9);
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add_disk(bdev->gendisk);
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return 0;
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out_queue:
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blk_cleanup_queue(rq);
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out:
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atomic_dec(&nr_devices);
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return ret;
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}
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void scm_blk_dev_cleanup(struct scm_blk_dev *bdev)
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{
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tasklet_kill(&bdev->tasklet);
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del_gendisk(bdev->gendisk);
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blk_cleanup_queue(bdev->gendisk->queue);
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put_disk(bdev->gendisk);
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}
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void scm_blk_set_available(struct scm_blk_dev *bdev)
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{
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unsigned long flags;
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spin_lock_irqsave(&bdev->lock, flags);
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if (bdev->state == SCM_WR_PROHIBIT)
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pr_info("%lx: Write access to the SCM increment is restored\n",
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(unsigned long) bdev->scmdev->address);
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bdev->state = SCM_OPER;
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spin_unlock_irqrestore(&bdev->lock, flags);
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}
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static int __init scm_blk_init(void)
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{
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int ret = -EINVAL;
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if (!scm_cluster_size_valid())
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goto out;
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ret = register_blkdev(0, "scm");
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if (ret < 0)
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goto out;
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scm_major = ret;
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ret = scm_alloc_rqs(nr_requests);
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if (ret)
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goto out_free;
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scm_debug = debug_register("scm_log", 16, 1, 16);
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if (!scm_debug) {
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ret = -ENOMEM;
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goto out_free;
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}
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debug_register_view(scm_debug, &debug_hex_ascii_view);
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debug_set_level(scm_debug, 2);
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ret = scm_drv_init();
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if (ret)
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goto out_dbf;
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return ret;
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out_dbf:
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debug_unregister(scm_debug);
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out_free:
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scm_free_rqs();
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unregister_blkdev(scm_major, "scm");
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out:
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return ret;
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}
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module_init(scm_blk_init);
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static void __exit scm_blk_cleanup(void)
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{
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scm_drv_cleanup();
|
|
debug_unregister(scm_debug);
|
|
scm_free_rqs();
|
|
unregister_blkdev(scm_major, "scm");
|
|
}
|
|
module_exit(scm_blk_cleanup);
|