diff mbox series

[v6,21/21] cxl/core: Split decoder setup into alloc + add

Message ID 163225205828.3038145.6831131648369404859.stgit@dwillia2-desk3.amr.corp.intel.com
State New, archived
Headers show
Series None | expand

Commit Message

Dan Williams Sept. 21, 2021, 7:22 p.m. UTC 
The kbuild robot reports:

    drivers/cxl/core/bus.c:516:1: warning: stack frame size (1032) exceeds
    limit (1024) in function 'devm_cxl_add_decoder'

It is also the case the devm_cxl_add_decoder() is unwieldy to use for
all the different decoder types. Fix the stack usage by splitting the
creation into alloc and add steps. This also allows for context
specific construction before adding.

With the split the caller is responsible for registering a devm callback
to trigger device_unregister() for the decoder rather than it being
implicit in the decoder registration. I.e. the routine that calls alloc
is responsible for calling put_device() if the "add" operation fails.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
Changes since v5:
- Add WARN_ON_ONCE() for the obvious programming error failure cases in
  cxl_decoder_add() (Ben)

- Mark @nr_targets in 'struct cxl_decoder' const (Ben)


 drivers/cxl/acpi.c      |   84 ++++++++++++++++++++++---------
 drivers/cxl/core/bus.c  |  129 +++++++++++++++--------------------------------
 drivers/cxl/core/core.h |    5 --
 drivers/cxl/core/pmem.c |    7 ++-
 drivers/cxl/cxl.h       |   15 ++---
 5 files changed, 114 insertions(+), 126 deletions(-)

Comments

Nathan Chancellor Dec. 10, 2021, 7:38 p.m. UTC | #1 
Hi Dan,

On Tue, Sep 21, 2021 at 12:22:16PM -0700, Dan Williams wrote:
> The kbuild robot reports:
> 
>     drivers/cxl/core/bus.c:516:1: warning: stack frame size (1032) exceeds
>     limit (1024) in function 'devm_cxl_add_decoder'
> 
> It is also the case the devm_cxl_add_decoder() is unwieldy to use for
> all the different decoder types. Fix the stack usage by splitting the
> creation into alloc and add steps. This also allows for context
> specific construction before adding.
> 
> With the split the caller is responsible for registering a devm callback
> to trigger device_unregister() for the decoder rather than it being
> implicit in the decoder registration. I.e. the routine that calls alloc
> is responsible for calling put_device() if the "add" operation fails.
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Nathan Chancellor <nathan@kernel.org>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Reviewed-by: Ben Widawsky <ben.widawsky@intel.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Apologies for not noticing this sooner, given that I was on the thread.

This patch as commit 48667f676189 ("cxl/core: Split decoder setup into
alloc + add") in mainline does not fully resolve the stack frame
warning. I still see an error with both GCC 11 and LLVM 12 with
allmodconfig minus CONFIG_KASAN.

GCC 11:

drivers/cxl/core/bus.c: In function ‘cxl_decoder_alloc’:
drivers/cxl/core/bus.c:523:1: error: the frame size of 1032 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
  523 | }
      | ^
cc1: all warnings being treated as errors

LLVM 12:

drivers/cxl/core/bus.c:486:21: error: stack frame size of 1056 bytes in function 'cxl_decoder_alloc' [-Werror,-Wframe-larger-than=]
struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port, int nr_targets)
                    ^
1 error generated.

This is due to the cxld_const_init structure, which is allocated on the
stack, presumably due to the "const" change requested in v5 that was
applied to v6. Undoing that resolves the warning for me with both
compilers. I am not sure if you have a better idea for how to resolve
that.

diff --git a/drivers/cxl/core/bus.c b/drivers/cxl/core/bus.c
index ebd061d03950..46ce58376580 100644
--- a/drivers/cxl/core/bus.c
+++ b/drivers/cxl/core/bus.c
@@ -485,9 +485,7 @@ static int decoder_populate_targets(struct cxl_decoder *cxld,
 
 struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port, int nr_targets)
 {
-	struct cxl_decoder *cxld, cxld_const_init = {
-		.nr_targets = nr_targets,
-	};
+	struct cxl_decoder *cxld;
 	struct device *dev;
 	int rc = 0;
 
@@ -497,13 +495,13 @@ struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port, int nr_targets)
 	cxld = kzalloc(struct_size(cxld, target, nr_targets), GFP_KERNEL);
 	if (!cxld)
 		return ERR_PTR(-ENOMEM);
-	memcpy(cxld, &cxld_const_init, sizeof(cxld_const_init));
 
 	rc = ida_alloc(&port->decoder_ida, GFP_KERNEL);
 	if (rc < 0)
 		goto err;
 
 	cxld->id = rc;
+	cxld->nr_targets = nr_targets;
 	dev = &cxld->dev;
 	device_initialize(dev);
 	device_set_pm_not_required(dev);
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 3af704e9b448..7c2b51746e31 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -191,7 +191,7 @@ struct cxl_decoder {
 	int interleave_granularity;
 	enum cxl_decoder_type target_type;
 	unsigned long flags;
-	const int nr_targets;
+	int nr_targets;
 	struct cxl_dport *target[];
 };
Dan Williams Dec. 10, 2021, 7:41 p.m. UTC | #2 
On Fri, Dec 10, 2021 at 11:39 AM Nathan Chancellor <nathan@kernel.org> wrote:
>
> Hi Dan,
>
> On Tue, Sep 21, 2021 at 12:22:16PM -0700, Dan Williams wrote:
> > The kbuild robot reports:
> >
> >     drivers/cxl/core/bus.c:516:1: warning: stack frame size (1032) exceeds
> >     limit (1024) in function 'devm_cxl_add_decoder'
> >
> > It is also the case the devm_cxl_add_decoder() is unwieldy to use for
> > all the different decoder types. Fix the stack usage by splitting the
> > creation into alloc and add steps. This also allows for context
> > specific construction before adding.
> >
> > With the split the caller is responsible for registering a devm callback
> > to trigger device_unregister() for the decoder rather than it being
> > implicit in the decoder registration. I.e. the routine that calls alloc
> > is responsible for calling put_device() if the "add" operation fails.
> >
> > Reported-by: kernel test robot <lkp@intel.com>
> > Reported-by: Nathan Chancellor <nathan@kernel.org>
> > Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> > Reviewed-by: Ben Widawsky <ben.widawsky@intel.com>
> > Signed-off-by: Dan Williams <dan.j.williams@intel.com>
>
> Apologies for not noticing this sooner, given that I was on the thread.
>
> This patch as commit 48667f676189 ("cxl/core: Split decoder setup into
> alloc + add") in mainline does not fully resolve the stack frame
> warning. I still see an error with both GCC 11 and LLVM 12 with
> allmodconfig minus CONFIG_KASAN.
>
> GCC 11:
>
> drivers/cxl/core/bus.c: In function ‘cxl_decoder_alloc’:
> drivers/cxl/core/bus.c:523:1: error: the frame size of 1032 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
>   523 | }
>       | ^
> cc1: all warnings being treated as errors
>
> LLVM 12:
>
> drivers/cxl/core/bus.c:486:21: error: stack frame size of 1056 bytes in function 'cxl_decoder_alloc' [-Werror,-Wframe-larger-than=]
> struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port, int nr_targets)
>                     ^
> 1 error generated.
>
> This is due to the cxld_const_init structure, which is allocated on the
> stack, presumably due to the "const" change requested in v5 that was
> applied to v6. Undoing that resolves the warning for me with both
> compilers. I am not sure if you have a better idea for how to resolve
> that.
>
> diff --git a/drivers/cxl/core/bus.c b/drivers/cxl/core/bus.c
> index ebd061d03950..46ce58376580 100644
> --- a/drivers/cxl/core/bus.c
> +++ b/drivers/cxl/core/bus.c
> @@ -485,9 +485,7 @@ static int decoder_populate_targets(struct cxl_decoder *cxld,
>
>  struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port, int nr_targets)
>  {
> -       struct cxl_decoder *cxld, cxld_const_init = {
> -               .nr_targets = nr_targets,
> -       };
> +       struct cxl_decoder *cxld;
>         struct device *dev;
>         int rc = 0;
>
> @@ -497,13 +495,13 @@ struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port, int nr_targets)
>         cxld = kzalloc(struct_size(cxld, target, nr_targets), GFP_KERNEL);
>         if (!cxld)
>                 return ERR_PTR(-ENOMEM);
> -       memcpy(cxld, &cxld_const_init, sizeof(cxld_const_init));
>
>         rc = ida_alloc(&port->decoder_ida, GFP_KERNEL);
>         if (rc < 0)
>                 goto err;
>
>         cxld->id = rc;
> +       cxld->nr_targets = nr_targets;
>         dev = &cxld->dev;
>         device_initialize(dev);
>         device_set_pm_not_required(dev);
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 3af704e9b448..7c2b51746e31 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -191,7 +191,7 @@ struct cxl_decoder {
>         int interleave_granularity;
>         enum cxl_decoder_type target_type;
>         unsigned long flags;
> -       const int nr_targets;
> +       int nr_targets;
>         struct cxl_dport *target[];

That change looks like the right way to go to me. Thanks for the follow-up!
diff mbox series

Patch

diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index d39cc797a64e..af1c6c1875ac 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -82,7 +82,6 @@  static void cxl_add_cfmws_decoders(struct device *dev,
 	struct cxl_decoder *cxld;
 	acpi_size len, cur = 0;
 	void *cedt_subtable;
-	unsigned long flags;
 	int rc;
 
 	len = acpi_cedt->length - sizeof(*acpi_cedt);
@@ -119,24 +118,36 @@  static void cxl_add_cfmws_decoders(struct device *dev,
 		for (i = 0; i < CFMWS_INTERLEAVE_WAYS(cfmws); i++)
 			target_map[i] = cfmws->interleave_targets[i];
 
-		flags = cfmws_to_decoder_flags(cfmws->restrictions);
-		cxld = devm_cxl_add_decoder(dev, root_port,
-					    CFMWS_INTERLEAVE_WAYS(cfmws),
-					    cfmws->base_hpa, cfmws->window_size,
-					    CFMWS_INTERLEAVE_WAYS(cfmws),
-					    CFMWS_INTERLEAVE_GRANULARITY(cfmws),
-					    CXL_DECODER_EXPANDER,
-					    flags, target_map);
-
-		if (IS_ERR(cxld)) {
+		cxld = cxl_decoder_alloc(root_port,
+					 CFMWS_INTERLEAVE_WAYS(cfmws));
+		if (IS_ERR(cxld))
+			goto next;
+
+		cxld->flags = cfmws_to_decoder_flags(cfmws->restrictions);
+		cxld->target_type = CXL_DECODER_EXPANDER;
+		cxld->range = (struct range) {
+			.start = cfmws->base_hpa,
+			.end = cfmws->base_hpa + cfmws->window_size - 1,
+		};
+		cxld->interleave_ways = CFMWS_INTERLEAVE_WAYS(cfmws);
+		cxld->interleave_granularity =
+			CFMWS_INTERLEAVE_GRANULARITY(cfmws);
+
+		rc = cxl_decoder_add(cxld, target_map);
+		if (rc)
+			put_device(&cxld->dev);
+		else
+			rc = cxl_decoder_autoremove(dev, cxld);
+		if (rc) {
 			dev_err(dev, "Failed to add decoder for %#llx-%#llx\n",
 				cfmws->base_hpa, cfmws->base_hpa +
 				cfmws->window_size - 1);
-		} else {
-			dev_dbg(dev, "add: %s range %#llx-%#llx\n",
-				dev_name(&cxld->dev), cfmws->base_hpa,
-				 cfmws->base_hpa + cfmws->window_size - 1);
+			goto next;
 		}
+		dev_dbg(dev, "add: %s range %#llx-%#llx\n",
+			dev_name(&cxld->dev), cfmws->base_hpa,
+			cfmws->base_hpa + cfmws->window_size - 1);
+next:
 		cur += c->length;
 	}
 }
@@ -266,6 +277,7 @@  static int add_host_bridge_uport(struct device *match, void *arg)
 	struct acpi_device *bridge = to_cxl_host_bridge(host, match);
 	struct acpi_pci_root *pci_root;
 	struct cxl_walk_context ctx;
+	int single_port_map[1], rc;
 	struct cxl_decoder *cxld;
 	struct cxl_dport *dport;
 	struct cxl_port *port;
@@ -301,22 +313,46 @@  static int add_host_bridge_uport(struct device *match, void *arg)
 		return -ENODEV;
 	if (ctx.error)
 		return ctx.error;
+	if (ctx.count > 1)
+		return 0;
 
 	/* TODO: Scan CHBCR for HDM Decoder resources */
 
 	/*
-	 * In the single-port host-bridge case there are no HDM decoders
-	 * in the CHBCR and a 1:1 passthrough decode is implied.
+	 * Per the CXL specification (8.2.5.12 CXL HDM Decoder Capability
+	 * Structure) single ported host-bridges need not publish a decoder
+	 * capability when a passthrough decode can be assumed, i.e. all
+	 * transactions that the uport sees are claimed and passed to the single
+	 * dport. Disable the range until the first CXL region is enumerated /
+	 * activated.
 	 */
-	if (ctx.count == 1) {
-		cxld = devm_cxl_add_passthrough_decoder(host, port);
-		if (IS_ERR(cxld))
-			return PTR_ERR(cxld);
+	cxld = cxl_decoder_alloc(port, 1);
+	if (IS_ERR(cxld))
+		return PTR_ERR(cxld);
+
+	cxld->interleave_ways = 1;
+	cxld->interleave_granularity = PAGE_SIZE;
+	cxld->target_type = CXL_DECODER_EXPANDER;
+	cxld->range = (struct range) {
+		.start = 0,
+		.end = -1,
+	};
 
-		dev_dbg(host, "add: %s\n", dev_name(&cxld->dev));
-	}
+	device_lock(&port->dev);
+	dport = list_first_entry(&port->dports, typeof(*dport), list);
+	device_unlock(&port->dev);
 
-	return 0;
+	single_port_map[0] = dport->port_id;
+
+	rc = cxl_decoder_add(cxld, single_port_map);
+	if (rc)
+		put_device(&cxld->dev);
+	else
+		rc = cxl_decoder_autoremove(host, cxld);
+
+	if (rc == 0)
+		dev_dbg(host, "add: %s\n", dev_name(&cxld->dev));
+	return rc;
 }
 
 static int add_host_bridge_dport(struct device *match, void *arg)
diff --git a/drivers/cxl/core/bus.c b/drivers/cxl/core/bus.c
index 6dfdeaf999f0..ebd061d03950 100644
--- a/drivers/cxl/core/bus.c
+++ b/drivers/cxl/core/bus.c
@@ -453,10 +453,8 @@  int cxl_add_dport(struct cxl_port *port, struct device *dport_dev, int port_id,
 }
 EXPORT_SYMBOL_GPL(cxl_add_dport);
 
-static int decoder_populate_targets(struct device *host,
-				    struct cxl_decoder *cxld,
-				    struct cxl_port *port, int *target_map,
-				    int nr_targets)
+static int decoder_populate_targets(struct cxl_decoder *cxld,
+				    struct cxl_port *port, int *target_map)
 {
 	int rc = 0, i;
 
@@ -464,66 +462,48 @@  static int decoder_populate_targets(struct device *host,
 		return 0;
 
 	device_lock(&port->dev);
-	for (i = 0; i < nr_targets; i++) {
+	if (list_empty(&port->dports)) {
+		rc = -EINVAL;
+		goto out_unlock;
+	}
+
+	for (i = 0; i < cxld->nr_targets; i++) {
 		struct cxl_dport *dport = find_dport(port, target_map[i]);
 
 		if (!dport) {
 			rc = -ENXIO;
-			break;
+			goto out_unlock;
 		}
-		dev_dbg(host, "%s: target: %d\n", dev_name(dport->dport), i);
 		cxld->target[i] = dport;
 	}
+
+out_unlock:
 	device_unlock(&port->dev);
 
 	return rc;
 }
 
-static struct cxl_decoder *
-cxl_decoder_alloc(struct device *host, struct cxl_port *port, int nr_targets,
-		  resource_size_t base, resource_size_t len,
-		  int interleave_ways, int interleave_granularity,
-		  enum cxl_decoder_type type, unsigned long flags,
-		  int *target_map)
+struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port, int nr_targets)
 {
-	struct cxl_decoder *cxld;
+	struct cxl_decoder *cxld, cxld_const_init = {
+		.nr_targets = nr_targets,
+	};
 	struct device *dev;
 	int rc = 0;
 
-	if (interleave_ways < 1)
+	if (nr_targets > CXL_DECODER_MAX_INTERLEAVE || nr_targets < 1)
 		return ERR_PTR(-EINVAL);
 
-	device_lock(&port->dev);
-	if (list_empty(&port->dports))
-		rc = -EINVAL;
-	device_unlock(&port->dev);
-	if (rc)
-		return ERR_PTR(rc);
-
 	cxld = kzalloc(struct_size(cxld, target, nr_targets), GFP_KERNEL);
 	if (!cxld)
 		return ERR_PTR(-ENOMEM);
+	memcpy(cxld, &cxld_const_init, sizeof(cxld_const_init));
 
 	rc = ida_alloc(&port->decoder_ida, GFP_KERNEL);
 	if (rc < 0)
 		goto err;
 
-	*cxld = (struct cxl_decoder) {
-		.id = rc,
-		.range = {
-			.start = base,
-			.end = base + len - 1,
-		},
-		.flags = flags,
-		.interleave_ways = interleave_ways,
-		.interleave_granularity = interleave_granularity,
-		.target_type = type,
-	};
-
-	rc = decoder_populate_targets(host, cxld, port, target_map, nr_targets);
-	if (rc)
-		goto err;
-
+	cxld->id = rc;
 	dev = &cxld->dev;
 	device_initialize(dev);
 	device_set_pm_not_required(dev);
@@ -541,72 +521,47 @@  cxl_decoder_alloc(struct device *host, struct cxl_port *port, int nr_targets,
 	kfree(cxld);
 	return ERR_PTR(rc);
 }
+EXPORT_SYMBOL_GPL(cxl_decoder_alloc);
 
-struct cxl_decoder *
-devm_cxl_add_decoder(struct device *host, struct cxl_port *port, int nr_targets,
-		     resource_size_t base, resource_size_t len,
-		     int interleave_ways, int interleave_granularity,
-		     enum cxl_decoder_type type, unsigned long flags,
-		     int *target_map)
+int cxl_decoder_add(struct cxl_decoder *cxld, int *target_map)
 {
-	struct cxl_decoder *cxld;
+	struct cxl_port *port;
 	struct device *dev;
 	int rc;
 
-	if (nr_targets > CXL_DECODER_MAX_INTERLEAVE)
-		return ERR_PTR(-EINVAL);
+	if (WARN_ON_ONCE(!cxld))
+		return -EINVAL;
 
-	cxld = cxl_decoder_alloc(host, port, nr_targets, base, len,
-				 interleave_ways, interleave_granularity, type,
-				 flags, target_map);
-	if (IS_ERR(cxld))
-		return cxld;
+	if (WARN_ON_ONCE(IS_ERR(cxld)))
+		return PTR_ERR(cxld);
 
-	dev = &cxld->dev;
-	rc = dev_set_name(dev, "decoder%d.%d", port->id, cxld->id);
-	if (rc)
-		goto err;
+	if (cxld->interleave_ways < 1)
+		return -EINVAL;
 
-	rc = device_add(dev);
+	port = to_cxl_port(cxld->dev.parent);
+	rc = decoder_populate_targets(cxld, port, target_map);
 	if (rc)
-		goto err;
+		return rc;
 
-	rc = devm_add_action_or_reset(host, unregister_cxl_dev, dev);
+	dev = &cxld->dev;
+	rc = dev_set_name(dev, "decoder%d.%d", port->id, cxld->id);
 	if (rc)
-		return ERR_PTR(rc);
-	return cxld;
+		return rc;
 
-err:
-	put_device(dev);
-	return ERR_PTR(rc);
+	return device_add(dev);
 }
-EXPORT_SYMBOL_GPL(devm_cxl_add_decoder);
+EXPORT_SYMBOL_GPL(cxl_decoder_add);
 
-/*
- * Per the CXL specification (8.2.5.12 CXL HDM Decoder Capability Structure)
- * single ported host-bridges need not publish a decoder capability when a
- * passthrough decode can be assumed, i.e. all transactions that the uport sees
- * are claimed and passed to the single dport. Default the range a 0-base
- * 0-length until the first CXL region is activated.
- */
-struct cxl_decoder *devm_cxl_add_passthrough_decoder(struct device *host,
-						     struct cxl_port *port)
+static void cxld_unregister(void *dev)
 {
-	struct cxl_dport *dport;
-	int target_map[1];
-
-	device_lock(&port->dev);
-	dport = list_first_entry_or_null(&port->dports, typeof(*dport), list);
-	device_unlock(&port->dev);
-
-	if (!dport)
-		return ERR_PTR(-ENXIO);
+	device_unregister(dev);
+}
 
-	target_map[0] = dport->port_id;
-	return devm_cxl_add_decoder(host, port, 1, 0, 0, 1, PAGE_SIZE,
-				    CXL_DECODER_EXPANDER, 0, target_map);
+int cxl_decoder_autoremove(struct device *host, struct cxl_decoder *cxld)
+{
+	return devm_add_action_or_reset(host, cxld_unregister, &cxld->dev);
 }
-EXPORT_SYMBOL_GPL(devm_cxl_add_passthrough_decoder);
+EXPORT_SYMBOL_GPL(cxl_decoder_autoremove);
 
 /**
  * __cxl_driver_register - register a driver for the cxl bus
diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index c85b7fbad02d..e0c9aacc4e9c 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -9,11 +9,6 @@  extern const struct device_type cxl_nvdimm_type;
 
 extern struct attribute_group cxl_base_attribute_group;
 
-static inline void unregister_cxl_dev(void *dev)
-{
-	device_unregister(dev);
-}
-
 struct cxl_send_command;
 struct cxl_mem_query_commands;
 int cxl_query_cmd(struct cxl_memdev *cxlmd,
diff --git a/drivers/cxl/core/pmem.c b/drivers/cxl/core/pmem.c
index 74be5132df1c..5032f4c1c69d 100644
--- a/drivers/cxl/core/pmem.c
+++ b/drivers/cxl/core/pmem.c
@@ -222,6 +222,11 @@  static struct cxl_nvdimm *cxl_nvdimm_alloc(struct cxl_memdev *cxlmd)
 	return cxl_nvd;
 }
 
+static void cxl_nvd_unregister(void *dev)
+{
+	device_unregister(dev);
+}
+
 /**
  * devm_cxl_add_nvdimm() - add a bridge between a cxl_memdev and an nvdimm
  * @host: same host as @cxlmd
@@ -251,7 +256,7 @@  int devm_cxl_add_nvdimm(struct device *host, struct cxl_memdev *cxlmd)
 	dev_dbg(host, "%s: register %s\n", dev_name(dev->parent),
 		dev_name(dev));
 
-	return devm_add_action_or_reset(host, unregister_cxl_dev, dev);
+	return devm_add_action_or_reset(host, cxl_nvd_unregister, dev);
 
 err:
 	put_device(dev);
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 9af5745ba2c0..a6687e7fd598 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -195,6 +195,7 @@  enum cxl_decoder_type {
  * @interleave_granularity: data stride per dport
  * @target_type: accelerator vs expander (type2 vs type3) selector
  * @flags: memory type capabilities and locking
+ * @nr_targets: number of elements in @target
  * @target: active ordered target list in current decoder configuration
  */
 struct cxl_decoder {
@@ -205,6 +206,7 @@  struct cxl_decoder {
 	int interleave_granularity;
 	enum cxl_decoder_type target_type;
 	unsigned long flags;
+	const int nr_targets;
 	struct cxl_dport *target[];
 };
 
@@ -286,15 +288,10 @@  int cxl_add_dport(struct cxl_port *port, struct device *dport, int port_id,
 
 struct cxl_decoder *to_cxl_decoder(struct device *dev);
 bool is_root_decoder(struct device *dev);
-struct cxl_decoder *
-devm_cxl_add_decoder(struct device *host, struct cxl_port *port, int nr_targets,
-		     resource_size_t base, resource_size_t len,
-		     int interleave_ways, int interleave_granularity,
-		     enum cxl_decoder_type type, unsigned long flags,
-		     int *target_map);
-
-struct cxl_decoder *devm_cxl_add_passthrough_decoder(struct device *host,
-						     struct cxl_port *port);
+struct cxl_decoder *cxl_decoder_alloc(struct cxl_port *port, int nr_targets);
+int cxl_decoder_add(struct cxl_decoder *cxld, int *target_map);
+int cxl_decoder_autoremove(struct device *host, struct cxl_decoder *cxld);
+
 extern struct bus_type cxl_bus_type;
 
 struct cxl_driver {