Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Martin Schwidefsky:
 "The most notable change for this pull request is the ftrace rework
  from Heiko.  It brings a small performance improvement and the ground
  work to support a new gcc option to replace the mcount blocks with a
  single nop.

  Two new s390 specific system calls are added to emulate user space
  mmio for PCI, an artifact of the how PCI memory is accessed.

  Two patches for the memory management with changes to common code.
  For KVM mm_forbids_zeropage is added which disables the empty zero
  page for an mm that is used by a KVM process.  And an optimization,
  pmdp_get_and_clear_full is added analog to ptep_get_and_clear_full.

  Some micro optimization for the cmpxchg and the spinlock code.

  And as usual bug fixes and cleanups"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (46 commits)
  s390/cputime: fix 31-bit compile
  s390/scm_block: make the number of reqs per HW req configurable
  s390/scm_block: handle multiple requests in one HW request
  s390/scm_block: allocate aidaw pages only when necessary
  s390/scm_block: use mempool to manage aidaw requests
  s390/eadm: change timeout value
  s390/mm: fix memory leak of ptlock in pmd_free_tlb
  s390: use local symbol names in entry[64].S
  s390/ptrace: always include vector registers in core files
  s390/simd: clear vector register pointer on fork/clone
  s390: translate cputime magic constants to macros
  s390/idle: convert open coded idle time seqcount
  s390/idle: add missing irq off lockdep annotation
  s390/debug: avoid function call for debug_sprintf_*
  s390/kprobes: fix instruction copy for out of line execution
  s390: remove diag 44 calls from cpu_relax()
  s390/dasd: retry partition detection
  s390/dasd: fix list corruption for sleep_on requests
  s390/dasd: fix infinite term I/O loop
  s390/dasd: remove unused code
  ...

1 files changed, 174 insertions, 48 deletions

diff --git a/drivers/s390/block/scm_blk.c b/drivers/s390/block/scm_blk.c
index 56046ab39629..75d9896deccb 100644
--- a/drivers/s390/block/scm_blk.c
+++ b/drivers/s390/block/scm_blk.c
@@ -10,6 +10,7 @@
 
 #include <linux/interrupt.h>
 #include <linux/spinlock.h>
+#include <linux/mempool.h>
 #include <linux/module.h>
 #include <linux/blkdev.h>
 #include <linux/genhd.h>
@@ -20,13 +21,18 @@
 
 debug_info_t *scm_debug;
 static int scm_major;
+static mempool_t *aidaw_pool;
 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*");
@@ -36,8 +42,8 @@ static void __scm_free_rq(struct scm_request *scmrq)
 	struct aob_rq_header *aobrq = to_aobrq(scmrq);
 
 	free_page((unsigned long) scmrq->aob);
-	free_page((unsigned long) scmrq->aidaw);
 	__scm_free_rq_cluster(scmrq);
+	kfree(scmrq->request);
 	kfree(aobrq);
 }
 
@@ -53,6 +59,8 @@ static void scm_free_rqs(void)
 		__scm_free_rq(scmrq);
 	}
 	spin_unlock_irq(&list_lock);
+
+	mempool_destroy(aidaw_pool);
 }
 
 static int __scm_alloc_rq(void)
@@ -65,17 +73,17 @@ static int __scm_alloc_rq(void)
 		return -ENOMEM;
 
 	scmrq = (void *) aobrq->data;
-	scmrq->aidaw = (void *) get_zeroed_page(GFP_DMA);
 	scmrq->aob = (void *) get_zeroed_page(GFP_DMA);
-	if (!scmrq->aob || !scmrq->aidaw) {
-		__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);
@@ -83,12 +91,19 @@ static int __scm_alloc_rq(void)
 	spin_unlock_irq(&list_lock);
 
 	return 0;
+free:
+	__scm_free_rq(scmrq);
+	return -ENOMEM;
 }
 
 static int scm_alloc_rqs(unsigned int nrqs)
 {
 	int ret = 0;
 
+	aidaw_pool = mempool_create_page_pool(max(nrqs/8, 1U), 0);
+	if (!aidaw_pool)
+		return -ENOMEM;
+
 	while (nrqs-- && !ret)
 		ret = __scm_alloc_rq();
 
@@ -112,6 +127,18 @@ out:
 static void scm_request_done(struct scm_request *scmrq)
 {
 	unsigned long flags;
+	struct msb *msb;
+	u64 aidaw;
+	int i;
+
+	for (i = 0; i < nr_requests_per_io && scmrq->request[i]; i++) {
+		msb = &scmrq->aob->msb[i];
+		aidaw = msb->data_addr;
+
+		if ((msb->flags & MSB_FLAG_IDA) && aidaw &&
+		    IS_ALIGNED(aidaw, PAGE_SIZE))
+			mempool_free(virt_to_page(aidaw), aidaw_pool);
+	}
 
 	spin_lock_irqsave(&list_lock, flags);
 	list_add(&scmrq->list, &inactive_requests);
@@ -123,48 +150,90 @@ static bool scm_permit_request(struct scm_blk_dev *bdev, struct request *req)
 	return rq_data_dir(req) != WRITE || bdev->state != SCM_WR_PROHIBIT;
 }
 
-static void scm_request_prepare(struct scm_request *scmrq)
+static inline struct aidaw *scm_aidaw_alloc(void)
+{
+	struct page *page = mempool_alloc(aidaw_pool, GFP_ATOMIC);
+
+	return page ? page_address(page) : NULL;
+}
+
+static inline unsigned long scm_aidaw_bytes(struct aidaw *aidaw)
+{
+	unsigned long _aidaw = (unsigned long) aidaw;
+	unsigned long bytes = ALIGN(_aidaw, PAGE_SIZE) - _aidaw;
+
+	return (bytes / sizeof(*aidaw)) * PAGE_SIZE;
+}
+
+struct aidaw *scm_aidaw_fetch(struct scm_request *scmrq, unsigned int bytes)
+{
+	struct aidaw *aidaw;
+
+	if (scm_aidaw_bytes(scmrq->next_aidaw) >= bytes)
+		return scmrq->next_aidaw;
+
+	aidaw = scm_aidaw_alloc();
+	if (aidaw)
+		memset(aidaw, 0, PAGE_SIZE);
+	return aidaw;
+}
+
+static int scm_request_prepare(struct scm_request *scmrq)
 {
 	struct scm_blk_dev *bdev = scmrq->bdev;
 	struct scm_device *scmdev = bdev->gendisk->private_data;
-	struct aidaw *aidaw = scmrq->aidaw;
-	struct msb *msb = &scmrq->aob->msb[0];
+	int pos = scmrq->aob->request.msb_count;
+	struct msb *msb = &scmrq->aob->msb[pos];
+	struct request *req = scmrq->request[pos];
 	struct req_iterator iter;
+	struct aidaw *aidaw;
 	struct bio_vec bv;
 
+	aidaw = scm_aidaw_fetch(scmrq, blk_rq_bytes(req));
+	if (!aidaw)
+		return -ENOMEM;
+
 	msb->bs = MSB_BS_4K;
-	scmrq->aob->request.msb_count = 1;
-	msb->scm_addr = scmdev->address +
-		((u64) blk_rq_pos(scmrq->request) << 9);
-	msb->oc = (rq_data_dir(scmrq->request) == READ) ?
-		MSB_OC_READ : MSB_OC_WRITE;
+	scmrq->aob->request.msb_count++;
+	msb->scm_addr = scmdev->address + ((u64) blk_rq_pos(req) << 9);
+	msb->oc = (rq_data_dir(req) == READ) ? MSB_OC_READ : MSB_OC_WRITE;
 	msb->flags |= MSB_FLAG_IDA;
 	msb->data_addr = (u64) aidaw;
 
-	rq_for_each_segment(bv, scmrq->request, iter) {
+	rq_for_each_segment(bv, req, iter) {
 		WARN_ON(bv.bv_offset);
 		msb->blk_count += bv.bv_len >> 12;
 		aidaw->data_addr = (u64) page_address(bv.bv_page);
 		aidaw++;
 	}
+
+	scmrq->next_aidaw = aidaw;
+	return 0;
+}
+
+static inline void scm_request_set(struct scm_request *scmrq,
+				   struct request *req)
+{
+	scmrq->request[scmrq->aob->request.msb_count] = req;
 }
 
 static inline void scm_request_init(struct scm_blk_dev *bdev,
-				    struct scm_request *scmrq,
-				    struct request *req)
+				    struct scm_request *scmrq)
 {
 	struct aob_rq_header *aobrq = to_aobrq(scmrq);
 	struct aob *aob = scmrq->aob;
 
+	memset(scmrq->request, 0,
+	       nr_requests_per_io * sizeof(scmrq->request[0]));
 	memset(aob, 0, sizeof(*aob));
-	memset(scmrq->aidaw, 0, PAGE_SIZE);
 	aobrq->scmdev = bdev->scmdev;
 	aob->request.cmd_code = ARQB_CMD_MOVE;
 	aob->request.data = (u64) aobrq;
-	scmrq->request = req;
 	scmrq->bdev = bdev;
 	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[nr_requests_per_io];
 	scm_request_cluster_init(scmrq);
 }
 
@@ -180,9 +249,12 @@ static void scm_ensure_queue_restart(struct scm_blk_dev *bdev)
 void scm_request_requeue(struct scm_request *scmrq)
 {
 	struct scm_blk_dev *bdev = scmrq->bdev;
+	int i;
 
 	scm_release_cluster(scmrq);
-	blk_requeue_request(bdev->rq, scmrq->request);
+	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);
 	scm_request_done(scmrq);
 	scm_ensure_queue_restart(bdev);
@@ -191,20 +263,41 @@ void scm_request_requeue(struct scm_request *scmrq)
 void scm_request_finish(struct scm_request *scmrq)
 {
 	struct scm_blk_dev *bdev = scmrq->bdev;
+	int i;
 
 	scm_release_cluster(scmrq);
-	blk_end_request_all(scmrq->request, scmrq->error);
+	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);
 	scm_request_done(scmrq);
 }
 
+static int scm_request_start(struct scm_request *scmrq)
+{
+	struct scm_blk_dev *bdev = scmrq->bdev;
+	int ret;
+
+	atomic_inc(&bdev->queued_reqs);
+	if (!scmrq->aob->request.msb_count) {
+		scm_request_requeue(scmrq);
+		return -EINVAL;
+	}
+
+	ret = eadm_start_aob(scmrq->aob);
+	if (ret) {
+		SCM_LOG(5, "no subchannel");
+		scm_request_requeue(scmrq);
+	}
+	return ret;
+}
+
 static void scm_blk_request(struct request_queue *rq)
 {
 	struct scm_device *scmdev = rq->queuedata;
 	struct scm_blk_dev *bdev = dev_get_drvdata(&scmdev->dev);
-	struct scm_request *scmrq;
+	struct scm_request *scmrq = NULL;
 	struct request *req;
-	int ret;
 
 	while ((req = blk_peek_request(rq))) {
 		if (req->cmd_type != REQ_TYPE_FS) {
@@ -214,39 +307,64 @@ static void scm_blk_request(struct request_queue *rq)
 			continue;
 		}
 
-		if (!scm_permit_request(bdev, req)) {
-			scm_ensure_queue_restart(bdev);
-			return;
-		}
-		scmrq = scm_request_fetch();
+		if (!scm_permit_request(bdev, req))
+			goto out;
+
 		if (!scmrq) {
-			SCM_LOG(5, "no request");
-			scm_ensure_queue_restart(bdev);
-			return;
+			scmrq = scm_request_fetch();
+			if (!scmrq) {
+				SCM_LOG(5, "no request");
+				goto out;
+			}
+			scm_request_init(bdev, scmrq);
 		}
-		scm_request_init(bdev, scmrq, req);
+		scm_request_set(scmrq, req);
+
 		if (!scm_reserve_cluster(scmrq)) {
 			SCM_LOG(5, "cluster busy");
+			scm_request_set(scmrq, NULL);
+			if (scmrq->aob->request.msb_count)
+				goto out;
+
 			scm_request_done(scmrq);
 			return;
 		}
+
 		if (scm_need_cluster_request(scmrq)) {
-			atomic_inc(&bdev->queued_reqs);
-			blk_start_request(req);
-			scm_initiate_cluster_request(scmrq);
-			return;
+			if (scmrq->aob->request.msb_count) {
+				/* Start cluster requests separately. */
+				scm_request_set(scmrq, NULL);
+				if (scm_request_start(scmrq))
+					return;
+			} else {
+				atomic_inc(&bdev->queued_reqs);
+				blk_start_request(req);
+				scm_initiate_cluster_request(scmrq);
+			}
+			scmrq = NULL;
+			continue;
+		}
+
+		if (scm_request_prepare(scmrq)) {
+			SCM_LOG(5, "aidaw alloc failed");
+			scm_request_set(scmrq, NULL);
+			goto out;
 		}
-		scm_request_prepare(scmrq);
-		atomic_inc(&bdev->queued_reqs);
 		blk_start_request(req);
 
-		ret = eadm_start_aob(scmrq->aob);
-		if (ret) {
-			SCM_LOG(5, "no subchannel");
-			scm_request_requeue(scmrq);
+		if (scmrq->aob->request.msb_count < nr_requests_per_io)
+			continue;
+
+		if (scm_request_start(scmrq))
 			return;
-		}
+
+		scmrq = NULL;
 	}
+out:
+	if (scmrq)
+		scm_request_start(scmrq);
+	else
+		scm_ensure_queue_restart(bdev);
 }
 
 static void __scmrq_log_error(struct scm_request *scmrq)
@@ -443,11 +561,19 @@ void scm_blk_set_available(struct scm_blk_dev *bdev)
 	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");