s390/scm_block: make the number of reqs per HW req configurable
Introduce a module parameter to specify the number of requests
we try to handle with one HW request.
Suggested-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/block/scm_blk.c b/drivers/s390/block/scm_blk.c
index cd27cb9..75d9896 100644
--- a/drivers/s390/block/scm_blk.c
+++ b/drivers/s390/block/scm_blk.c
@@ -25,10 +25,14 @@
static DEFINE_SPINLOCK(list_lock);
static LIST_HEAD(inactive_requests);
static unsigned int nr_requests = 64;
+static unsigned int nr_requests_per_io = 8;
static atomic_t nr_devices = ATOMIC_INIT(0);
module_param(nr_requests, uint, S_IRUGO);
MODULE_PARM_DESC(nr_requests, "Number of parallel requests.");
+module_param(nr_requests_per_io, uint, S_IRUGO);
+MODULE_PARM_DESC(nr_requests_per_io, "Number of requests per IO.");
+
MODULE_DESCRIPTION("Block driver for s390 storage class memory.");
MODULE_LICENSE("GPL");
MODULE_ALIAS("scm:scmdev*");
@@ -39,6 +43,7 @@
free_page((unsigned long) scmrq->aob);
__scm_free_rq_cluster(scmrq);
+ kfree(scmrq->request);
kfree(aobrq);
}
@@ -69,15 +74,16 @@
scmrq = (void *) aobrq->data;
scmrq->aob = (void *) get_zeroed_page(GFP_DMA);
- if (!scmrq->aob) {
- __scm_free_rq(scmrq);
- return -ENOMEM;
- }
+ if (!scmrq->aob)
+ goto free;
- if (__scm_alloc_rq_cluster(scmrq)) {
- __scm_free_rq(scmrq);
- return -ENOMEM;
- }
+ scmrq->request = kcalloc(nr_requests_per_io, sizeof(scmrq->request[0]),
+ GFP_KERNEL);
+ if (!scmrq->request)
+ goto free;
+
+ if (__scm_alloc_rq_cluster(scmrq))
+ goto free;
INIT_LIST_HEAD(&scmrq->list);
spin_lock_irq(&list_lock);
@@ -85,6 +91,9 @@
spin_unlock_irq(&list_lock);
return 0;
+free:
+ __scm_free_rq(scmrq);
+ return -ENOMEM;
}
static int scm_alloc_rqs(unsigned int nrqs)
@@ -122,7 +131,7 @@
u64 aidaw;
int i;
- for (i = 0; i < SCM_RQ_PER_IO && scmrq->request[i]; i++) {
+ for (i = 0; i < nr_requests_per_io && scmrq->request[i]; i++) {
msb = &scmrq->aob->msb[i];
aidaw = msb->data_addr;
@@ -214,7 +223,8 @@
struct aob_rq_header *aobrq = to_aobrq(scmrq);
struct aob *aob = scmrq->aob;
- memset(scmrq->request, 0, sizeof(scmrq->request));
+ memset(scmrq->request, 0,
+ nr_requests_per_io * sizeof(scmrq->request[0]));
memset(aob, 0, sizeof(*aob));
aobrq->scmdev = bdev->scmdev;
aob->request.cmd_code = ARQB_CMD_MOVE;
@@ -223,7 +233,7 @@
scmrq->retries = 4;
scmrq->error = 0;
/* We don't use all msbs - place aidaws at the end of the aob page. */
- scmrq->next_aidaw = (void *) &aob->msb[SCM_RQ_PER_IO];
+ scmrq->next_aidaw = (void *) &aob->msb[nr_requests_per_io];
scm_request_cluster_init(scmrq);
}
@@ -242,7 +252,7 @@
int i;
scm_release_cluster(scmrq);
- for (i = 0; i < SCM_RQ_PER_IO && scmrq->request[i]; i++)
+ for (i = 0; i < nr_requests_per_io && scmrq->request[i]; i++)
blk_requeue_request(bdev->rq, scmrq->request[i]);
atomic_dec(&bdev->queued_reqs);
@@ -256,7 +266,7 @@
int i;
scm_release_cluster(scmrq);
- for (i = 0; i < SCM_RQ_PER_IO && scmrq->request[i]; i++)
+ for (i = 0; i < nr_requests_per_io && scmrq->request[i]; i++)
blk_end_request_all(scmrq->request[i], scmrq->error);
atomic_dec(&bdev->queued_reqs);
@@ -342,7 +352,7 @@
}
blk_start_request(req);
- if (scmrq->aob->request.msb_count < SCM_RQ_PER_IO)
+ if (scmrq->aob->request.msb_count < nr_requests_per_io)
continue;
if (scm_request_start(scmrq))
@@ -551,11 +561,19 @@
spin_unlock_irqrestore(&bdev->lock, flags);
}
+static bool __init scm_blk_params_valid(void)
+{
+ if (!nr_requests_per_io || nr_requests_per_io > 64)
+ return false;
+
+ return scm_cluster_size_valid();
+}
+
static int __init scm_blk_init(void)
{
int ret = -EINVAL;
- if (!scm_cluster_size_valid())
+ if (!scm_blk_params_valid())
goto out;
ret = register_blkdev(0, "scm");