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Message-ID: <20251119192236.2527305-2-alejandro.lucero-palau@amd.com>
Date: Wed, 19 Nov 2025 19:22:14 +0000
From: <alejandro.lucero-palau@....com>
To: <linux-cxl@...r.kernel.org>, <netdev@...r.kernel.org>,
<dan.j.williams@...el.com>, <edward.cree@....com>, <davem@...emloft.net>,
<kuba@...nel.org>, <pabeni@...hat.com>, <edumazet@...gle.com>,
<dave.jiang@...el.com>
CC: Alejandro Lucero <alucerop@....com>
Subject: [PATCH v21 01/23] cxl/mem: refactor memdev allocation
From: Alejandro Lucero <alucerop@....com>
In preparation for always-synchronous memdev attach, refactor memdev
allocation and fix release bug in devm_cxl_add_memdev() when error after
a successful allocation.
The diff is busy as this moves cxl_memdev_alloc() down below the definition
of cxl_memdev_fops and introduces devm_cxl_memdev_add_or_reset() to
preclude needing to export more symbols from the cxl_core.
Fixes: 1c3333a28d45 ("cxl/mem: Do not rely on device_add() side effects for dev_set_name() failures")
Signed-off-by: Dan Williams <dan.j.williams@...el.com>
Signed-off-by: Alejandro Lucero <alucerop@....com>
---
drivers/cxl/core/memdev.c | 134 +++++++++++++++++++++-----------------
drivers/cxl/private.h | 10 +++
2 files changed, 86 insertions(+), 58 deletions(-)
create mode 100644 drivers/cxl/private.h
diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
index e370d733e440..8de19807ac7b 100644
--- a/drivers/cxl/core/memdev.c
+++ b/drivers/cxl/core/memdev.c
@@ -8,6 +8,7 @@
#include <linux/idr.h>
#include <linux/pci.h>
#include <cxlmem.h>
+#include "private.h"
#include "trace.h"
#include "core.h"
@@ -648,42 +649,25 @@ static void detach_memdev(struct work_struct *work)
static struct lock_class_key cxl_memdev_key;
-static struct cxl_memdev *cxl_memdev_alloc(struct cxl_dev_state *cxlds,
- const struct file_operations *fops)
+int devm_cxl_memdev_add_or_reset(struct device *host, struct cxl_memdev *cxlmd)
{
- struct cxl_memdev *cxlmd;
- struct device *dev;
- struct cdev *cdev;
+ struct device *dev = &cxlmd->dev;
+ struct cdev *cdev = &cxlmd->cdev;
int rc;
- cxlmd = kzalloc(sizeof(*cxlmd), GFP_KERNEL);
- if (!cxlmd)
- return ERR_PTR(-ENOMEM);
-
- rc = ida_alloc_max(&cxl_memdev_ida, CXL_MEM_MAX_DEVS - 1, GFP_KERNEL);
- if (rc < 0)
- goto err;
- cxlmd->id = rc;
- cxlmd->depth = -1;
-
- dev = &cxlmd->dev;
- device_initialize(dev);
- lockdep_set_class(&dev->mutex, &cxl_memdev_key);
- dev->parent = cxlds->dev;
- dev->bus = &cxl_bus_type;
- dev->devt = MKDEV(cxl_mem_major, cxlmd->id);
- dev->type = &cxl_memdev_type;
- device_set_pm_not_required(dev);
- INIT_WORK(&cxlmd->detach_work, detach_memdev);
-
- cdev = &cxlmd->cdev;
- cdev_init(cdev, fops);
- return cxlmd;
+ rc = cdev_device_add(cdev, dev);
+ if (rc) {
+ /*
+ * The cdev was briefly live, shutdown any ioctl operations that
+ * saw that state.
+ */
+ cxl_memdev_shutdown(dev);
+ return rc;
+ }
-err:
- kfree(cxlmd);
- return ERR_PTR(rc);
+ return devm_add_action_or_reset(host, cxl_memdev_unregister, cxlmd);
}
+EXPORT_SYMBOL_NS_GPL(devm_cxl_memdev_add_or_reset, "CXL");
static long __cxl_memdev_ioctl(struct cxl_memdev *cxlmd, unsigned int cmd,
unsigned long arg)
@@ -1051,48 +1035,82 @@ static const struct file_operations cxl_memdev_fops = {
.llseek = noop_llseek,
};
-struct cxl_memdev *devm_cxl_add_memdev(struct device *host,
- struct cxl_dev_state *cxlds)
+struct cxl_memdev *cxl_memdev_alloc(struct cxl_dev_state *cxlds)
{
- struct cxl_memdev *cxlmd;
+ struct cxl_memdev *cxlmd __free(kfree) =
+ kzalloc(sizeof(*cxlmd), GFP_KERNEL);
struct device *dev;
struct cdev *cdev;
int rc;
- cxlmd = cxl_memdev_alloc(cxlds, &cxl_memdev_fops);
- if (IS_ERR(cxlmd))
- return cxlmd;
-
- dev = &cxlmd->dev;
- rc = dev_set_name(dev, "mem%d", cxlmd->id);
- if (rc)
- goto err;
+ if (!cxlmd)
+ return ERR_PTR(-ENOMEM);
- /*
- * Activate ioctl operations, no cxl_memdev_rwsem manipulation
- * needed as this is ordered with cdev_add() publishing the device.
- */
+ rc = ida_alloc_max(&cxl_memdev_ida, CXL_MEM_MAX_DEVS - 1, GFP_KERNEL);
+ if (rc < 0)
+ return ERR_PTR(rc);
+ cxlmd->id = rc;
+ cxlmd->depth = -1;
cxlmd->cxlds = cxlds;
cxlds->cxlmd = cxlmd;
+ dev = &cxlmd->dev;
+ device_initialize(dev);
+ lockdep_set_class(&dev->mutex, &cxl_memdev_key);
+ dev->parent = cxlds->dev;
+ dev->bus = &cxl_bus_type;
+ dev->devt = MKDEV(cxl_mem_major, cxlmd->id);
+ dev->type = &cxl_memdev_type;
+ device_set_pm_not_required(dev);
+ INIT_WORK(&cxlmd->detach_work, detach_memdev);
+
cdev = &cxlmd->cdev;
- rc = cdev_device_add(cdev, dev);
+ cdev_init(cdev, &cxl_memdev_fops);
+ return_ptr(cxlmd);
+}
+EXPORT_SYMBOL_NS_GPL(cxl_memdev_alloc, "CXL");
+
+static void __cxlmd_free(struct cxl_memdev *cxlmd)
+{
+ if (IS_ERR(cxlmd))
+ return;
+
+ if (cxlmd->cxlds)
+ cxlmd->cxlds->cxlmd = NULL;
+
+ put_device(&cxlmd->dev);
+ kfree(cxlmd);
+}
+
+DEFINE_FREE(cxlmd_free, struct cxl_memdev *, __cxlmd_free(_T))
+
+/**
+ * devm_cxl_add_memdev - Add a CXL memory device
+ * @host: devres alloc/release context and parent for the memdev
+ * @cxlds: CXL device state to associate with the memdev
+ *
+ * Upon return the device will have had a chance to attach to the
+ * cxl_mem driver, but may fail if the CXL topology is not ready
+ * (hardware CXL link down, or software platform CXL root not attached)
+ */
+struct cxl_memdev *devm_cxl_add_memdev(struct device *host,
+ struct cxl_dev_state *cxlds)
+{
+ struct cxl_memdev *cxlmd __free(cxlmd_free) = cxl_memdev_alloc(cxlds);
+ int rc;
+
+ if (IS_ERR(cxlmd))
+ return cxlmd;
+
+ rc = dev_set_name(&cxlmd->dev, "mem%d", cxlmd->id);
if (rc)
- goto err;
+ return ERR_PTR(rc);
- rc = devm_add_action_or_reset(host, cxl_memdev_unregister, cxlmd);
+ rc = devm_cxl_memdev_add_or_reset(host, cxlmd);
if (rc)
return ERR_PTR(rc);
- return cxlmd;
-err:
- /*
- * The cdev was briefly live, shutdown any ioctl operations that
- * saw that state.
- */
- cxl_memdev_shutdown(dev);
- put_device(dev);
- return ERR_PTR(rc);
+ return no_free_ptr(cxlmd);
}
EXPORT_SYMBOL_NS_GPL(devm_cxl_add_memdev, "CXL");
diff --git a/drivers/cxl/private.h b/drivers/cxl/private.h
new file mode 100644
index 000000000000..50c2ac57afb5
--- /dev/null
+++ b/drivers/cxl/private.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright(c) 2025 Intel Corporation. */
+
+/* Private interfaces betwen common drivers ("cxl_mem") and the cxl_core */
+
+#ifndef __CXL_PRIVATE_H__
+#define __CXL_PRIVATE_H__
+struct cxl_memdev *cxl_memdev_alloc(struct cxl_dev_state *cxlds);
+int devm_cxl_memdev_add_or_reset(struct device *host, struct cxl_memdev *cxlmd);
+#endif /* __CXL_PRIVATE_H__ */
--
2.34.1
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