s390/dasd: move dasd_ccw_req to per request data

Let the block layer allocate per request data to store
struct dasd_ccw_req. We still need extra preallocated
memory for usage by ccw programs (which vary in length)
and for requests which don't originate from the block
layer.

Link: https://lkml.kernel.org/r/20180530074130.GA6927@infradead.org
Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 24 insertions, 22 deletions

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 790b1fa3fec0e..01a1d1dabb43d 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -1267,35 +1267,37 @@ struct dasd_ccw_req *dasd_kmalloc_request(int magic, int cplength,
 }
 EXPORT_SYMBOL(dasd_kmalloc_request);
 
-struct dasd_ccw_req *dasd_smalloc_request(int magic, int cplength,
-					  int datasize,
-					  struct dasd_device *device)
+struct dasd_ccw_req *dasd_smalloc_request(int magic, int cplength, int datasize,
+					  struct dasd_device *device,
+					  struct dasd_ccw_req *cqr)
 {
 	unsigned long flags;
-	struct dasd_ccw_req *cqr;
-	char *data;
-	int size;
+	char *data, *chunk;
+	int size = 0;
 
-	size = (sizeof(struct dasd_ccw_req) + 7L) & -8L;
 	if (cplength > 0)
 		size += cplength * sizeof(struct ccw1);
 	if (datasize > 0)
 		size += datasize;
+	if (!cqr)
+		size += (sizeof(*cqr) + 7L) & -8L;
+
 	spin_lock_irqsave(&device->mem_lock, flags);
-	cqr = (struct dasd_ccw_req *)
-		dasd_alloc_chunk(&device->ccw_chunks, size);
+	data = chunk = dasd_alloc_chunk(&device->ccw_chunks, size);
 	spin_unlock_irqrestore(&device->mem_lock, flags);
-	if (cqr == NULL)
+	if (!chunk)
 		return ERR_PTR(-ENOMEM);
-	memset(cqr, 0, sizeof(struct dasd_ccw_req));
-	data = (char *) cqr + ((sizeof(struct dasd_ccw_req) + 7L) & -8L);
-	cqr->cpaddr = NULL;
+	if (!cqr) {
+		cqr = (void *) data;
+		data += (sizeof(*cqr) + 7L) & -8L;
+	}
+	memset(cqr, 0, sizeof(*cqr));
+	cqr->mem_chunk = chunk;
 	if (cplength > 0) {
-		cqr->cpaddr = (struct ccw1 *) data;
-		data += cplength*sizeof(struct ccw1);
-		memset(cqr->cpaddr, 0, cplength*sizeof(struct ccw1));
+		cqr->cpaddr = data;
+		data += cplength * sizeof(struct ccw1);
+		memset(cqr->cpaddr, 0, cplength * sizeof(struct ccw1));
 	}
-	cqr->data = NULL;
 	if (datasize > 0) {
 		cqr->data = data;
  		memset(cqr->data, 0, datasize);
@@ -1333,7 +1335,7 @@ void dasd_sfree_request(struct dasd_ccw_req *cqr, struct dasd_device *device)
 	unsigned long flags;
 
 	spin_lock_irqsave(&device->mem_lock, flags);
-	dasd_free_chunk(&device->ccw_chunks, cqr);
+	dasd_free_chunk(&device->ccw_chunks, cqr->mem_chunk);
 	spin_unlock_irqrestore(&device->mem_lock, flags);
 	dasd_put_device(device);
 }
@@ -3046,7 +3048,6 @@ static blk_status_t do_dasd_request(struct blk_mq_hw_ctx *hctx,
 	cqr->callback_data = req;
 	cqr->status = DASD_CQR_FILLED;
 	cqr->dq = dq;
-	*((struct dasd_ccw_req **) blk_mq_rq_to_pdu(req)) = cqr;
 
 	blk_mq_start_request(req);
 	spin_lock(&block->queue_lock);
@@ -3077,7 +3078,7 @@ enum blk_eh_timer_return dasd_times_out(struct request *req, bool reserved)
 	unsigned long flags;
 	int rc = 0;
 
-	cqr = *((struct dasd_ccw_req **) blk_mq_rq_to_pdu(req));
+	cqr = blk_mq_rq_to_pdu(req);
 	if (!cqr)
 		return BLK_EH_DONE;
 
@@ -3179,7 +3180,7 @@ static int dasd_alloc_queue(struct dasd_block *block)
 	int rc;
 
 	block->tag_set.ops = &dasd_mq_ops;
-	block->tag_set.cmd_size = sizeof(struct dasd_ccw_req *);
+	block->tag_set.cmd_size = sizeof(struct dasd_ccw_req);
 	block->tag_set.nr_hw_queues = DASD_NR_HW_QUEUES;
 	block->tag_set.queue_depth = DASD_MAX_LCU_DEV * DASD_REQ_PER_DEV;
 	block->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
@@ -4043,7 +4044,8 @@ static struct dasd_ccw_req *dasd_generic_build_rdc(struct dasd_device *device,
 	struct ccw1 *ccw;
 	unsigned long *idaw;
 
-	cqr = dasd_smalloc_request(magic, 1 /* RDC */, rdc_buffer_size, device);
+	cqr = dasd_smalloc_request(magic, 1 /* RDC */, rdc_buffer_size, device,
+				   NULL);
 
 	if (IS_ERR(cqr)) {
 		/* internal error 13 - Allocating the RDC request failed*/