[GIT PULL] two more s390 bug fixes for 4.17

[GIT PULL] two more s390 bug fixes for 4.17

[Martin Schwidefsky]

Hi Linus,

please pull from the 'for-linus' branch of

	git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git for-linus

to receive the following updates:

Two bug fixes for 4.17

 * A missing -msoft-float for the compile of the kexec purgatory

 * A fix for the dasd driver to avoid the double use of a field in
   the 'struct request'

Philipp Rudo (1):
      s390/purgatory: Fix endless interrupt loop

Sebastian Ott (1):
      s390/dasd: use blk_mq_rq_from_pdu for per request data

 arch/s390/purgatory/Makefile | 2 +-
 drivers/s390/block/dasd.c    | 7 +++++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/s390/purgatory/Makefile b/arch/s390/purgatory/Makefile
index e9525bc..1ace023 100644
--- a/arch/s390/purgatory/Makefile
+++ b/arch/s390/purgatory/Makefile
@@ -21,7 +21,7 @@ LDFLAGS_purgatory.ro += -z nodefaultlib
 KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes
 KBUILD_CFLAGS += -Wno-pointer-sign -Wno-sign-compare
 KBUILD_CFLAGS += -fno-zero-initialized-in-bss -fno-builtin -ffreestanding
-KBUILD_CFLAGS += -c -MD -Os -m64
+KBUILD_CFLAGS += -c -MD -Os -m64 -msoft-float
 KBUILD_CFLAGS += $(call cc-option,-fno-PIE)
 
 $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 04143c0..02c03e4 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -3034,7 +3034,8 @@ 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;
-	req->completion_data = cqr;
+	*((struct dasd_ccw_req **) blk_mq_rq_to_pdu(req)) = cqr;
+
 	blk_mq_start_request(req);
 	spin_lock(&block->queue_lock);
 	list_add_tail(&cqr->blocklist, &block->ccw_queue);
@@ -3058,12 +3059,13 @@ static blk_status_t do_dasd_request(struct blk_mq_hw_ctx *hctx,
  */
 enum blk_eh_timer_return dasd_times_out(struct request *req, bool reserved)
 {
-	struct dasd_ccw_req *cqr = req->completion_data;
 	struct dasd_block *block = req->q->queuedata;
 	struct dasd_device *device;
+	struct dasd_ccw_req *cqr;
 	unsigned long flags;
 	int rc = 0;
 
+	cqr = *((struct dasd_ccw_req **) blk_mq_rq_to_pdu(req));
 	if (!cqr)
 		return BLK_EH_NOT_HANDLED;
 
@@ -3169,6 +3171,7 @@ 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.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;

Re: [GIT PULL] two more s390 bug fixes for 4.17

[Christoph Hellwig]

> -	req->completion_data = cqr;
> +	*((struct dasd_ccw_req **) blk_mq_rq_to_pdu(req)) = cqr;
> +

Please don't play such tricks.  In general your driver structure
should have struct request embedded.  If for some reason
struct dasd_ccw_req has a different life time please create a new
structure instead of these hacks.

In either way this really doesn't look like a post-rc7 change.

Re: [GIT PULL] two more s390 bug fixes for 4.17

[Martin Schwidefsky]

On Wed, 30 May 2018 00:41:30 -0700
Christoph Hellwig <hch@infradead.org> wrote:

> > -	req->completion_data = cqr;
> > +	*((struct dasd_ccw_req **) blk_mq_rq_to_pdu(req)) = cqr;
> > +  
> 
> Please don't play such tricks.  In general your driver structure
> should have struct request embedded.  If for some reason
> struct dasd_ccw_req has a different life time please create a new
> structure instead of these hacks.

Why do you consider this to be a 'trick'? The blk_mq_rq_to_pdu is
meant to be used to access a block of data that is is associated
with a request, no? With the change we store a single value, the
pointer to a struct dasd_ccw_req. The struct request comes first,
later do_dasd_request creates the struct dasd_ccw_req with the
CCW chain for the request. And for the blk timeout handler we need
a way to find the dasd_ccw_req again.

> In either way this really doesn't look like a post-rc7 change.

You think so? It fixes a crash for s390 with a minimal number of
changed lines:

 drivers/s390/block/dasd.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

-- 
blue skies,
   Martin.

"Reality continues to ruin my life." - Calvin.

Re: [GIT PULL] two more s390 bug fixes for 4.17

[Christoph Hellwig]

On Wed, May 30, 2018 at 11:11:40AM +0200, Martin Schwidefsky wrote:
> On Wed, 30 May 2018 00:41:30 -0700
> Christoph Hellwig <hch@infradead.org> wrote:
> 
> > > -	req->completion_data = cqr;
> > > +	*((struct dasd_ccw_req **) blk_mq_rq_to_pdu(req)) = cqr;
> > > +  
> > 
> > Please don't play such tricks.  In general your driver structure
> > should have struct request embedded.  If for some reason
> > struct dasd_ccw_req has a different life time please create a new
> > structure instead of these hacks.
> 
> Why do you consider this to be a 'trick'? The blk_mq_rq_to_pdu is
> meant to be used to access a block of data that is is associated
> with a request, no? With the change we store a single value, the
> pointer to a struct dasd_ccw_req. The struct request comes first,
> later do_dasd_request creates the struct dasd_ccw_req with the
> CCW chain for the request. And for the blk timeout handler we need
> a way to find the dasd_ccw_req again.

We'll we try really hard to have a structure that we can use
container_of on.  At least a minimal container with just the pointer
for a quick fix, but in general it seems like you should be able
to allocate the whole dasd_ccw_req with the request and just initialize
it later.

Re: [GIT PULL] two more s390 bug fixes for 4.17

[Martin Schwidefsky]

On Thu, 31 May 2018 09:14:00 -0700
Christoph Hellwig <hch@infradead.org> wrote:

> On Wed, May 30, 2018 at 11:11:40AM +0200, Martin Schwidefsky wrote:
> > On Wed, 30 May 2018 00:41:30 -0700
> > Christoph Hellwig <hch@infradead.org> wrote:
> >   
> > > > -	req->completion_data = cqr;
> > > > +	*((struct dasd_ccw_req **) blk_mq_rq_to_pdu(req)) = cqr;
> > > > +    
> > > 
> > > Please don't play such tricks.  In general your driver structure
> > > should have struct request embedded.  If for some reason
> > > struct dasd_ccw_req has a different life time please create a new
> > > structure instead of these hacks.  
> > 
> > Why do you consider this to be a 'trick'? The blk_mq_rq_to_pdu is
> > meant to be used to access a block of data that is is associated
> > with a request, no? With the change we store a single value, the
> > pointer to a struct dasd_ccw_req. The struct request comes first,
> > later do_dasd_request creates the struct dasd_ccw_req with the
> > CCW chain for the request. And for the blk timeout handler we need
> > a way to find the dasd_ccw_req again.  
> 
> We'll we try really hard to have a structure that we can use
> container_of on.  At least a minimal container with just the pointer
> for a quick fix, but in general it seems like you should be able
> to allocate the whole dasd_ccw_req with the request and just initialize
> it later.

A minimal container with a pointer is easy enough to do. To replace
our allocation scheme for the CCW chains will be hard. For one there
are internal I/Os that do not have an associated 'struct request'.
For those we need to allocate the memory on our own anyway.
Then the size of the memory block you need for the CCW varies wildly
and can be quite large. The tag cmd_size is fixed at the time
blk_mq_alloc_tag_set is called. If we replace out allocation scheme
this would force us to use the maximum size CCW chain for the
tag size, no?

-- 
blue skies,
   Martin.

"Reality continues to ruin my life." - Calvin.

Re: [GIT PULL] two more s390 bug fixes for 4.17

[Sebastian Ott]

On Wed, 30 May 2018, Christoph Hellwig wrote:

> > -	req->completion_data = cqr;
> > +	*((struct dasd_ccw_req **) blk_mq_rq_to_pdu(req)) = cqr;
> > +
> 
> Please don't play such tricks.  In general your driver structure
> should have struct request embedded.  If for some reason
> struct dasd_ccw_req has a different life time please create a new
> structure instead of these hacks.

Would you agree that this is an improvement over using completion_data
(at least now we don't mess with the block layers internal data)?

I already looked into what needs to be done to put struct dasd_ccw_req
behind the request and let it be managed by the block layer.

My concerns are lifetime and memory constraints (some of our HW interfaces
still use 31 bit pointers) but I think both of these are manageable with
the blk-mq interfaces.

But this would not be a small change and nothing for rc7. Would you be
OK with doing the small fix now and I'll work on the mentioned
improvement?

Regards,
Sebastian

Re: [GIT PULL] two more s390 bug fixes for 4.17

[Sebastian Ott]

Hello,

On Wed, 30 May 2018, Sebastian Ott wrote:
> On Wed, 30 May 2018, Christoph Hellwig wrote:
> > > -	req->completion_data = cqr;
> > > +	*((struct dasd_ccw_req **) blk_mq_rq_to_pdu(req)) = cqr;
> > > +
> > 
> > Please don't play such tricks.  In general your driver structure
> > should have struct request embedded.

OK. I did that. Executive summary:

@@ -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_NOT_HANDLED;
 
@@ -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);


If you agree with this I'll prepare that one for inclusion via Martins
tree.

Regards,
Sebastian

------->8

>From 72470aaf8721e3cff9aac9f1095c22c66164eb7f Mon Sep 17 00:00:00 2001
From: Sebastian Ott <sebott@linux.ibm.com>
Date: Mon, 4 Jun 2018 19:07:39 +0200
Subject: [PATCH] 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>
---
 drivers/s390/block/dasd.c      | 46 ++++++++++++++++++++++--------------------
 drivers/s390/block/dasd_diag.c |  3 ++-
 drivers/s390/block/dasd_eckd.c | 46 +++++++++++++++++++++++-------------------
 drivers/s390/block/dasd_fba.c  |  6 ++++--
 drivers/s390/block/dasd_int.h  |  3 ++-
 5 files changed, 57 insertions(+), 47 deletions(-)

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index ed039ab..a8ffbac 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_NOT_HANDLED;
 
@@ -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*/
diff --git a/drivers/s390/block/dasd_diag.c b/drivers/s390/block/dasd_diag.c
index 131f198..e1fe024 100644
--- a/drivers/s390/block/dasd_diag.c
+++ b/drivers/s390/block/dasd_diag.c
@@ -536,7 +536,8 @@ static struct dasd_ccw_req *dasd_diag_build_cp(struct dasd_device *memdev,
 	/* Build the request */
 	datasize = sizeof(struct dasd_diag_req) +
 		count*sizeof(struct dasd_diag_bio);
-	cqr = dasd_smalloc_request(DASD_DIAG_MAGIC, 0, datasize, memdev);
+	cqr = dasd_smalloc_request(DASD_DIAG_MAGIC, 0, datasize, memdev,
+				   blk_mq_rq_to_pdu(req));
 	if (IS_ERR(cqr))
 		return cqr;
 
diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index be208e7..bbf95b7 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -886,7 +886,7 @@ static int dasd_eckd_read_conf_lpm(struct dasd_device *device,
 	}
 	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* RCD */,
 				   0, /* use rcd_buf as data ara */
-				   device);
+				   device, NULL);
 	if (IS_ERR(cqr)) {
 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 			      "Could not allocate RCD request");
@@ -1442,7 +1442,7 @@ static int dasd_eckd_read_features(struct dasd_device *device)
 	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */	+ 1 /* RSSD */,
 				   (sizeof(struct dasd_psf_prssd_data) +
 				    sizeof(struct dasd_rssd_features)),
-				   device);
+				   device, NULL);
 	if (IS_ERR(cqr)) {
 		DBF_EVENT_DEVID(DBF_WARNING, device->cdev, "%s", "Could not "
 				"allocate initialization request");
@@ -1504,7 +1504,7 @@ static struct dasd_ccw_req *dasd_eckd_build_psf_ssc(struct dasd_device *device,
 
 	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */ ,
 				  sizeof(struct dasd_psf_ssc_data),
-				  device);
+				   device, NULL);
 
 	if (IS_ERR(cqr)) {
 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
@@ -1815,7 +1815,8 @@ dasd_eckd_analysis_ccw(struct dasd_device *device)
 
 	cplength = 8;
 	datasize = sizeof(struct DE_eckd_data) + 2*sizeof(struct LO_eckd_data);
-	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, cplength, datasize, device);
+	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, cplength, datasize, device,
+				   NULL);
 	if (IS_ERR(cqr))
 		return cqr;
 	ccw = cqr->cpaddr;
@@ -2092,7 +2093,8 @@ dasd_eckd_build_check_tcw(struct dasd_device *base, struct format_data_t *fdata,
 	 */
 	itcw_size = itcw_calc_size(0, count, 0);
 
-	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 0, itcw_size, startdev);
+	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 0, itcw_size, startdev,
+				   NULL);
 	if (IS_ERR(cqr))
 		return cqr;
 
@@ -2186,7 +2188,7 @@ dasd_eckd_build_check(struct dasd_device *base, struct format_data_t *fdata,
 	cplength += count;
 
 	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, cplength, datasize,
-				  startdev);
+				   startdev, NULL);
 	if (IS_ERR(cqr))
 		return cqr;
 
@@ -2332,7 +2334,7 @@ dasd_eckd_build_format(struct dasd_device *base,
 	}
 	/* Allocate the format ccw request. */
 	fcp = dasd_smalloc_request(DASD_ECKD_MAGIC, cplength,
-				   datasize, startdev);
+				   datasize, startdev, NULL);
 	if (IS_ERR(fcp))
 		return fcp;
 
@@ -3103,7 +3105,7 @@ static struct dasd_ccw_req *dasd_eckd_build_cp_cmd_single(
 	}
 	/* Allocate the ccw request. */
 	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, cplength, datasize,
-				   startdev);
+				   startdev, blk_mq_rq_to_pdu(req));
 	if (IS_ERR(cqr))
 		return cqr;
 	ccw = cqr->cpaddr;
@@ -3262,7 +3264,7 @@ static struct dasd_ccw_req *dasd_eckd_build_cp_cmd_track(
 
 	/* Allocate the ccw request. */
 	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, cplength, datasize,
-				   startdev);
+				   startdev, blk_mq_rq_to_pdu(req));
 	if (IS_ERR(cqr))
 		return cqr;
 	ccw = cqr->cpaddr;
@@ -3595,7 +3597,8 @@ static struct dasd_ccw_req *dasd_eckd_build_cp_tpm_track(
 
 	/* Allocate the ccw request. */
 	itcw_size = itcw_calc_size(0, ctidaw, 0);
-	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 0, itcw_size, startdev);
+	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 0, itcw_size, startdev,
+				   blk_mq_rq_to_pdu(req));
 	if (IS_ERR(cqr))
 		return cqr;
 
@@ -3862,7 +3865,7 @@ static struct dasd_ccw_req *dasd_eckd_build_cp_raw(struct dasd_device *startdev,
 
 	/* Allocate the ccw request. */
 	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, cplength,
-				   datasize, startdev);
+				   datasize, startdev, blk_mq_rq_to_pdu(req));
 	if (IS_ERR(cqr))
 		return cqr;
 
@@ -4102,7 +4105,7 @@ dasd_eckd_release(struct dasd_device *device)
 		return -EACCES;
 
 	useglobal = 0;
-	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1, 32, device);
+	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1, 32, device, NULL);
 	if (IS_ERR(cqr)) {
 		mutex_lock(&dasd_reserve_mutex);
 		useglobal = 1;
@@ -4157,7 +4160,7 @@ dasd_eckd_reserve(struct dasd_device *device)
 		return -EACCES;
 
 	useglobal = 0;
-	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1, 32, device);
+	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1, 32, device, NULL);
 	if (IS_ERR(cqr)) {
 		mutex_lock(&dasd_reserve_mutex);
 		useglobal = 1;
@@ -4211,7 +4214,7 @@ dasd_eckd_steal_lock(struct dasd_device *device)
 		return -EACCES;
 
 	useglobal = 0;
-	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1, 32, device);
+	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1, 32, device, NULL);
 	if (IS_ERR(cqr)) {
 		mutex_lock(&dasd_reserve_mutex);
 		useglobal = 1;
@@ -4271,7 +4274,8 @@ static int dasd_eckd_snid(struct dasd_device *device,
 
 	useglobal = 0;
 	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1,
-				   sizeof(struct dasd_snid_data), device);
+				   sizeof(struct dasd_snid_data), device,
+				   NULL);
 	if (IS_ERR(cqr)) {
 		mutex_lock(&dasd_reserve_mutex);
 		useglobal = 1;
@@ -4331,7 +4335,7 @@ dasd_eckd_performance(struct dasd_device *device, void __user *argp)
 	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */  + 1 /* RSSD */,
 				   (sizeof(struct dasd_psf_prssd_data) +
 				    sizeof(struct dasd_rssd_perf_stats_t)),
-				   device);
+				   device, NULL);
 	if (IS_ERR(cqr)) {
 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 			    "Could not allocate initialization request");
@@ -4477,7 +4481,7 @@ static int dasd_symm_io(struct dasd_device *device, void __user *argp)
 	psf1 = psf_data[1];
 
 	/* setup CCWs for PSF + RSSD */
-	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 2 , 0, device);
+	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 2, 0, device, NULL);
 	if (IS_ERR(cqr)) {
 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
 			"Could not allocate initialization request");
@@ -5037,7 +5041,7 @@ static int dasd_eckd_read_message_buffer(struct dasd_device *device,
 	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */	+ 1 /* RSSD */,
 				   (sizeof(struct dasd_psf_prssd_data) +
 				    sizeof(struct dasd_rssd_messages)),
-				   device);
+				   device, NULL);
 	if (IS_ERR(cqr)) {
 		DBF_EVENT_DEVID(DBF_WARNING, device->cdev, "%s",
 				"Could not allocate read message buffer request");
@@ -5126,7 +5130,7 @@ static int dasd_eckd_query_host_access(struct dasd_device *device,
 
 	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */	+ 1 /* RSSD */,
 				   sizeof(struct dasd_psf_prssd_data) + 1,
-				   device);
+				   device, NULL);
 	if (IS_ERR(cqr)) {
 		DBF_EVENT_DEVID(DBF_WARNING, device->cdev, "%s",
 				"Could not allocate read message buffer request");
@@ -5284,8 +5288,8 @@ dasd_eckd_psf_cuir_response(struct dasd_device *device, int response,
 	int rc;
 
 	cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* PSF */ ,
-				  sizeof(struct dasd_psf_cuir_response),
-				  device);
+				   sizeof(struct dasd_psf_cuir_response),
+				   device, NULL);
 
 	if (IS_ERR(cqr)) {
 		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
diff --git a/drivers/s390/block/dasd_fba.c b/drivers/s390/block/dasd_fba.c
index a6b132f..56007a3 100644
--- a/drivers/s390/block/dasd_fba.c
+++ b/drivers/s390/block/dasd_fba.c
@@ -356,7 +356,8 @@ static struct dasd_ccw_req *dasd_fba_build_cp_discard(
 	datasize = sizeof(struct DE_fba_data) +
 		nr_ccws * (sizeof(struct LO_fba_data) + sizeof(struct ccw1));
 
-	cqr = dasd_smalloc_request(DASD_FBA_MAGIC, cplength, datasize, memdev);
+	cqr = dasd_smalloc_request(DASD_FBA_MAGIC, cplength, datasize, memdev,
+				   blk_mq_rq_to_pdu(req));
 	if (IS_ERR(cqr))
 		return cqr;
 
@@ -490,7 +491,8 @@ static struct dasd_ccw_req *dasd_fba_build_cp_regular(
 		datasize += (count - 1)*sizeof(struct LO_fba_data);
 	}
 	/* Allocate the ccw request. */
-	cqr = dasd_smalloc_request(DASD_FBA_MAGIC, cplength, datasize, memdev);
+	cqr = dasd_smalloc_request(DASD_FBA_MAGIC, cplength, datasize, memdev,
+				   blk_mq_rq_to_pdu(req));
 	if (IS_ERR(cqr))
 		return cqr;
 	ccw = cqr->cpaddr;
diff --git a/drivers/s390/block/dasd_int.h b/drivers/s390/block/dasd_int.h
index 96709b1..0844e5e 100644
--- a/drivers/s390/block/dasd_int.h
+++ b/drivers/s390/block/dasd_int.h
@@ -184,6 +184,7 @@ struct dasd_ccw_req {
 	struct irb irb;			/* device status in case of an error */
 	struct dasd_ccw_req *refers;	/* ERP-chain queueing. */
 	void *function; 		/* originating ERP action */
+	void *mem_chunk;
 
 	/* these are for statistics only */
 	unsigned long buildclk;		/* TOD-clock of request generation */
@@ -716,7 +717,7 @@ extern struct kmem_cache *dasd_page_cache;
 struct dasd_ccw_req *
 dasd_kmalloc_request(int , int, int, struct dasd_device *);
 struct dasd_ccw_req *
-dasd_smalloc_request(int , int, int, struct dasd_device *);
+dasd_smalloc_request(int, int, int, struct dasd_device *, struct dasd_ccw_req *);
 void dasd_kfree_request(struct dasd_ccw_req *, struct dasd_device *);
 void dasd_sfree_request(struct dasd_ccw_req *, struct dasd_device *);
 void dasd_wakeup_cb(struct dasd_ccw_req *, void *);
-- 
2.7.4