[PATCH v18 03/13] cxl: Tighten CPER kfifo registration API and symbol visibility
From: Terry Bowman
Date: Fri Jul 17 2026 - 18:30:06 EST
From: Dan Williams <djbw@xxxxxxxxxx>
Tighten the CPER protocol error kfifo registration API and symbol
visibility.
Use EXPORT_SYMBOL_FOR_MODULES() instead of EXPORT_SYMBOL_NS_GPL() for
the CPER kfifo registration symbols. This names the consuming module
explicitly and gives compile-time enforcement.
Drop the work_struct argument from the unregister path. Change the
WARN_ONCE condition to a NULL check since there is no caller pointer
to compare against anymore.
Change register/unregister return types to void. Flag double registration
with WARN_ONCE() inside the lock instead of returning an error.
Change cxl_ras_init() to void because there is one consumer and one producer
so the error return was unnecessary. Remove the now-dead error check in
cxl_core_init().
Add a diagnostic log when the driver is not bound in
cxl_cper_handle_prot_err().
Co-developed-by: Terry Bowman <terry.bowman@xxxxxxx>
Signed-off-by: Terry Bowman <terry.bowman@xxxxxxx>
Signed-off-by: Dan Williams <djbw@xxxxxxxxxx>
---
Changes in v17 -> v18:
- New patch.
---
drivers/acpi/apei/ghes.c | 32 +++++++++++++++-----------------
drivers/cxl/core/core.h | 7 ++-----
drivers/cxl/core/port.c | 6 +-----
drivers/cxl/core/ras.c | 12 +++++++-----
include/cxl/event.h | 17 ++++++-----------
5 files changed, 31 insertions(+), 43 deletions(-)
diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index ca7a138c1ff2e..187f54e31c33e 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -778,41 +778,41 @@ static void cxl_cper_post_prot_err(struct cxl_cper_sec_prot_err *prot_err,
#endif
}
-int cxl_cper_register_prot_err_work(struct work_struct *work)
+void cxl_cper_register_prot_err_work(struct work_struct *work)
{
guard(raw_spinlock_irqsave)(&cxl_cper_prot_err_work_lock);
if (WARN_ONCE(cxl_cper_prot_err_work,
"CPER-CXL kfifo consumer already registered\n"))
- return -EINVAL;
+ return;
cxl_cper_prot_err_work = work;
- return 0;
}
-EXPORT_SYMBOL_NS_GPL(cxl_cper_register_prot_err_work, "CXL");
+EXPORT_SYMBOL_FOR_MODULES(cxl_cper_register_prot_err_work, "cxl_core");
-int cxl_cper_unregister_prot_err_work(struct work_struct *work)
+void cxl_cper_unregister_prot_err_work(void)
{
+ struct work_struct *old;
+
scoped_guard(raw_spinlock_irqsave, &cxl_cper_prot_err_work_lock) {
- if (WARN_ONCE(cxl_cper_prot_err_work != work,
- "CPER-CXL kfifo consumer mismatch on unregister\n"))
- return -EINVAL;
+ WARN_ONCE(!cxl_cper_prot_err_work,
+ "CPER-CXL kfifo consumer not registered on unregister\n");
+ old = cxl_cper_prot_err_work;
cxl_cper_prot_err_work = NULL;
}
- cancel_work_sync(work);
+ if (old)
+ cancel_work_sync(old);
/* Discard stale entries so they are not replayed on next module load */
kfifo_reset(&cxl_cper_prot_err_fifo);
-
- return 0;
}
-EXPORT_SYMBOL_NS_GPL(cxl_cper_unregister_prot_err_work, "CXL");
+EXPORT_SYMBOL_FOR_MODULES(cxl_cper_unregister_prot_err_work, "cxl_core");
int cxl_cper_prot_err_kfifo_get(struct cxl_cper_prot_err_work_data *wd)
{
return kfifo_get(&cxl_cper_prot_err_fifo, wd);
}
-EXPORT_SYMBOL_NS_GPL(cxl_cper_prot_err_kfifo_get, "CXL");
+EXPORT_SYMBOL_FOR_MODULES(cxl_cper_prot_err_kfifo_get, "cxl_core");
/* Room for 8 entries for each of the 4 event log queues */
#define CXL_CPER_FIFO_DEPTH 32
@@ -867,12 +867,12 @@ int cxl_cper_register_work(struct work_struct *work)
}
EXPORT_SYMBOL_NS_GPL(cxl_cper_register_work, "CXL");
-int cxl_cper_unregister_work(struct work_struct *work)
+void cxl_cper_unregister_work(struct work_struct *work)
{
scoped_guard(raw_spinlock_irqsave, &cxl_cper_work_lock) {
if (WARN_ONCE(cxl_cper_work != work,
"CXL CPER kfifo consumer mismatch on unregister\n"))
- return -EINVAL;
+ return;
cxl_cper_work = NULL;
}
@@ -880,8 +880,6 @@ int cxl_cper_unregister_work(struct work_struct *work)
/* Discard stale entries so they are not replayed on next module load */
kfifo_reset(&cxl_cper_fifo);
-
- return 0;
}
EXPORT_SYMBOL_NS_GPL(cxl_cper_unregister_work, "CXL");
diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index 07555ae638594..23fe40ddf4c6b 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -183,7 +183,7 @@ static inline struct device *dport_to_host(struct cxl_dport *dport)
return &port->dev;
}
#ifdef CONFIG_CXL_RAS
-int cxl_ras_init(void);
+void cxl_ras_init(void);
void cxl_ras_exit(void);
bool cxl_handle_ras(struct device *dev, void __iomem *ras_base);
void cxl_handle_cor_ras(struct device *dev, void __iomem *ras_base);
@@ -192,10 +192,7 @@ void cxl_disable_rch_root_ints(struct cxl_dport *dport);
void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds);
void devm_cxl_dport_ras_setup(struct cxl_dport *dport);
#else
-static inline int cxl_ras_init(void)
-{
- return 0;
-}
+static inline void cxl_ras_init(void) { }
static inline void cxl_ras_exit(void) { }
static inline bool cxl_handle_ras(struct device *dev, void __iomem *ras_base)
{
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 1215ee4f40351..f90f899c31d07 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -2531,14 +2531,10 @@ static __init int cxl_core_init(void)
if (rc)
goto err_region;
- rc = cxl_ras_init();
- if (rc)
- goto err_ras;
+ cxl_ras_init();
return 0;
-err_ras:
- cxl_region_exit();
err_region:
bus_unregister(&cxl_bus_type);
err_bus:
diff --git a/drivers/cxl/core/ras.c b/drivers/cxl/core/ras.c
index 99fb00949c2fa..135f1997e6f4f 100644
--- a/drivers/cxl/core/ras.c
+++ b/drivers/cxl/core/ras.c
@@ -104,8 +104,11 @@ void cxl_cper_handle_prot_err(struct cxl_cper_prot_err_work_data *data)
}
guard(device)(&pdev->dev);
- if (!pdev->dev.driver)
+ if (!pdev->dev.driver) {
+ dev_warn_ratelimited(&pdev->dev,
+ "Device is unbound, abort CPER error handling\n");
return;
+ }
struct device *mem_dev __free(put_device) = bus_find_device(
&cxl_bus_type, NULL, pdev, match_memdev_by_parent);
@@ -129,15 +132,14 @@ static void cxl_cper_prot_err_work_fn(struct work_struct *work)
}
static DECLARE_WORK(cxl_cper_prot_err_work, cxl_cper_prot_err_work_fn);
-int cxl_ras_init(void)
+void cxl_ras_init(void)
{
- return cxl_cper_register_prot_err_work(&cxl_cper_prot_err_work);
+ cxl_cper_register_prot_err_work(&cxl_cper_prot_err_work);
}
void cxl_ras_exit(void)
{
- cxl_cper_unregister_prot_err_work(&cxl_cper_prot_err_work);
- cancel_work_sync(&cxl_cper_prot_err_work);
+ cxl_cper_unregister_prot_err_work();
}
static void cxl_dport_map_ras(struct cxl_dport *dport)
diff --git a/include/cxl/event.h b/include/cxl/event.h
index ff97fea718d2c..3471d4f75c025 100644
--- a/include/cxl/event.h
+++ b/include/cxl/event.h
@@ -287,10 +287,10 @@ struct cxl_cper_prot_err_work_data {
#ifdef CONFIG_ACPI_APEI_GHES
int cxl_cper_register_work(struct work_struct *work);
-int cxl_cper_unregister_work(struct work_struct *work);
+void cxl_cper_unregister_work(struct work_struct *work);
int cxl_cper_kfifo_get(struct cxl_cper_work_data *wd);
-int cxl_cper_register_prot_err_work(struct work_struct *work);
-int cxl_cper_unregister_prot_err_work(struct work_struct *work);
+void cxl_cper_register_prot_err_work(struct work_struct *work);
+void cxl_cper_unregister_prot_err_work(void);
int cxl_cper_prot_err_kfifo_get(struct cxl_cper_prot_err_work_data *wd);
#else
static inline int cxl_cper_register_work(struct work_struct *work)
@@ -298,21 +298,16 @@ static inline int cxl_cper_register_work(struct work_struct *work)
return 0;
}
-static inline int cxl_cper_unregister_work(struct work_struct *work)
-{
- return 0;
-}
+static inline void cxl_cper_unregister_work(struct work_struct *work) { }
static inline int cxl_cper_kfifo_get(struct cxl_cper_work_data *wd)
{
return 0;
}
-static inline int cxl_cper_register_prot_err_work(struct work_struct *work)
+static inline void cxl_cper_register_prot_err_work(struct work_struct *work)
{
- return 0;
}
-static inline int cxl_cper_unregister_prot_err_work(struct work_struct *work)
+static inline void cxl_cper_unregister_prot_err_work(void)
{
- return 0;
}
static inline int cxl_cper_prot_err_kfifo_get(struct cxl_cper_prot_err_work_data *wd)
{
--
2.34.1