[PATCH v2 05/10] PCI: Share the AER ratelimit sysfs accessors

[Yazen Ghannam]

The show and store paths for a ratelimit_state exposed through sysfs are
the same whichever capability owns the state. Only the expression that
reaches the ratelimit_state differs.

Move the bodies into pci-sysfs.c as four helpers taking a
ratelimit_state, and add PCI_RATELIMIT_INTERVAL_ATTR() and
PCI_RATELIMIT_BURST_ATTR() to generate the attribute pair around them.
Convert AER to use them.

The Makefile builds pci-sysfs.c only under CONFIG_SYSFS, so build the
AER attributes under it too. They were dead code without it, since
pci_dev_attr_groups[] is their only consumer, but they were still
emitted and now reference the shared helpers.

No functional change intended.

Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@xxxxxxx>
---
 drivers/pci/pci-sysfs.c | 68 ++++++++++++++++++++++++++++++
 drivers/pci/pci.h       | 49 ++++++++++++++++++++++
 drivers/pci/pcie/aer.c  | 93 +++++++----------------------------------
 3 files changed, 131 insertions(+), 79 deletions(-)

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 1f21856aac8a..a111e62e39b3 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -29,6 +29,7 @@
 #include <linux/pm_runtime.h>
 #include <linux/msi.h>
 #include <linux/of.h>
+#include <linux/ratelimit.h>
 #include <linux/aperture.h>
 #include <linux/unaligned.h>
 #include "pci.h"
@@ -1892,6 +1893,73 @@ static const struct attribute_group pci_dev_group = {
 	.attrs = pci_dev_attrs,
 };
 
+/*
+ * Accessors shared by the capabilities that expose a struct ratelimit_state
+ * through sysfs. Use them via PCI_RATELIMIT_INTERVAL_ATTR() and
+ * PCI_RATELIMIT_BURST_ATTR() rather than calling them directly.
+ */
+ssize_t pci_ratelimit_interval_show(struct ratelimit_state *rs, char *buf)
+{
+	unsigned long iv = rs->interval;
+
+	return sysfs_emit(buf, "%u\n", jiffies_to_msecs(iv));
+}
+
+/*
+ * Ratelimit interval, in milliseconds
+ * <=0: disabled with ratelimit.interval = 0
+ * >0: enabled, ratelimit.interval held in jiffies
+ */
+ssize_t pci_ratelimit_interval_store(struct ratelimit_state *rs,
+				     const char *buf, size_t count)
+{
+	int interval;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (kstrtoint(buf, 0, &interval) < 0)
+		return -EINVAL;
+
+	if (interval <= 0)
+		interval = 0;
+	else
+		interval = msecs_to_jiffies(interval);
+
+	rs->interval = interval;
+
+	return count;
+}
+
+ssize_t pci_ratelimit_burst_show(struct ratelimit_state *rs, char *buf)
+{
+	return sysfs_emit(buf, "%d\n", rs->burst);
+}
+
+/*
+ * Ratelimit burst
+ * <=0: everything suppressed, unless the interval is also 0
+ * >0: messages allowed per interval
+ */
+ssize_t pci_ratelimit_burst_store(struct ratelimit_state *rs,
+				  const char *buf, size_t count)
+{
+	int burst;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (kstrtoint(buf, 0, &burst) < 0)
+		return -EINVAL;
+
+	if (burst < 0)
+		burst = 0;
+
+	rs->burst = burst;
+
+	return count;
+}
+
 const struct attribute_group *pci_dev_groups[] = {
 	&pci_dev_group,
 #if defined(HAVE_PCI_MMAP) || defined(ARCH_GENERIC_PCI_MMAP_RESOURCE)
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index f5fdb5dffdb7..f43c5330fca3 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -9,6 +9,7 @@
 #include <trace/events/pci.h>
 
 struct pcie_tlp_log;
+struct ratelimit_state;
 
 /* Number of possible devfns: 0.0 to 1f.7 inclusive */
 #define MAX_NR_DEVFNS 256
@@ -74,6 +75,54 @@ struct pcie_tlp_log;
 #define PCIE_LINK_WAIT_MAX_RETRIES	10
 #define PCIE_LINK_WAIT_SLEEP_MS		90
 
+ssize_t pci_ratelimit_interval_show(struct ratelimit_state *rs, char *buf);
+ssize_t pci_ratelimit_interval_store(struct ratelimit_state *rs,
+				     const char *buf, size_t count);
+ssize_t pci_ratelimit_burst_show(struct ratelimit_state *rs, char *buf);
+ssize_t pci_ratelimit_burst_store(struct ratelimit_state *rs,
+				  const char *buf, size_t count);
+
+/*
+ * Define the "<name>" sysfs attribute for the interval or the burst of a
+ * struct ratelimit_state. @member names it within struct pci_dev, so it
+ * reads as e.g. aer_info->correctable_ratelimit.
+ */
+#define PCI_RATELIMIT_INTERVAL_ATTR(name, member)			\
+	static ssize_t name##_show(struct device *dev,			\
+				   struct device_attribute *attr,	\
+				   char *buf)				\
+	{								\
+		return pci_ratelimit_interval_show(			\
+				&to_pci_dev(dev)->member, buf);		\
+	}								\
+									\
+	static ssize_t name##_store(struct device *dev,			\
+				    struct device_attribute *attr,	\
+				    const char *buf, size_t count)	\
+	{								\
+		return pci_ratelimit_interval_store(			\
+				&to_pci_dev(dev)->member, buf, count);	\
+	}								\
+	static DEVICE_ATTR_RW(name)
+
+#define PCI_RATELIMIT_BURST_ATTR(name, member)				\
+	static ssize_t name##_show(struct device *dev,			\
+				   struct device_attribute *attr,	\
+				   char *buf)				\
+	{								\
+		return pci_ratelimit_burst_show(			\
+				&to_pci_dev(dev)->member, buf);		\
+	}								\
+									\
+	static ssize_t name##_store(struct device *dev,			\
+				    struct device_attribute *attr,	\
+				    const char *buf, size_t count)	\
+	{								\
+		return pci_ratelimit_burst_store(			\
+				&to_pci_dev(dev)->member, buf, count);	\
+	}								\
+	static DEVICE_ATTR_RW(name)
+
 /* Format of TLP; PCIe r7.0, sec 2.2.1 */
 #define PCIE_TLP_FMT_3DW_NO_DATA	0x00 /* 3DW header, no data */
 #define PCIE_TLP_FMT_4DW_NO_DATA	0x01 /* 4DW header, no data */
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 91d73bd2ca7c..f42b57cac28a 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -599,6 +599,12 @@ static const char *aer_agent_string[] = {
 	"",
 };
 
+/*
+ * pci_dev_attr_groups[] in pci-sysfs.c is the only consumer of the groups
+ * below, and the ratelimit accessors they are built from live there too.
+ */
+#ifdef CONFIG_SYSFS
+
 #define aer_stats_dev_attr(name, stats_array, strings_array,		\
 			   total_string, total_field)			\
 	static ssize_t							\
@@ -687,87 +693,14 @@ const struct attribute_group aer_stats_attr_group = {
 	.is_visible = aer_stats_attrs_are_visible,
 };
 
-/*
- * Ratelimit interval, in milliseconds
- * <=0: disabled with ratelimit.interval = 0
- * >0: enabled, ratelimit.interval held in jiffies
- */
-#define aer_ratelimit_interval_attr(name, ratelimit)			\
-	static ssize_t							\
-	name##_show(struct device *dev, struct device_attribute *attr,	\
-					 char *buf)			\
-	{								\
-		struct pci_dev *pdev = to_pci_dev(dev);			\
-		unsigned long iv = pdev->aer_info->ratelimit.interval;	\
-									\
-		return sysfs_emit(buf, "%u\n", jiffies_to_msecs(iv));	\
-	}								\
-									\
-	static ssize_t							\
-	name##_store(struct device *dev, struct device_attribute *attr, \
-		     const char *buf, size_t count) 			\
-	{								\
-		struct pci_dev *pdev = to_pci_dev(dev);			\
-		int interval;						\
-									\
-		if (!capable(CAP_SYS_ADMIN))				\
-			return -EPERM;					\
-									\
-		if (kstrtoint(buf, 0, &interval) < 0)			\
-			return -EINVAL;					\
-									\
-		if (interval <= 0)					\
-			interval = 0;					\
-		else							\
-			interval = msecs_to_jiffies(interval); 		\
-									\
-		pdev->aer_info->ratelimit.interval = interval;		\
-									\
-		return count;						\
-	}								\
-	static DEVICE_ATTR_RW(name);
-
-#define aer_ratelimit_burst_attr(name, ratelimit)			\
-	static ssize_t							\
-	name##_show(struct device *dev, struct device_attribute *attr,	\
-		    char *buf)						\
-	{								\
-		struct pci_dev *pdev = to_pci_dev(dev);			\
-									\
-		return sysfs_emit(buf, "%d\n",				\
-				  pdev->aer_info->ratelimit.burst);	\
-	}								\
-									\
-	static ssize_t							\
-	name##_store(struct device *dev, struct device_attribute *attr,	\
-		     const char *buf, size_t count)			\
-	{								\
-		struct pci_dev *pdev = to_pci_dev(dev);			\
-		int burst;						\
-									\
-		if (!capable(CAP_SYS_ADMIN))				\
-			return -EPERM;					\
-									\
-		if (kstrtoint(buf, 0, &burst) < 0)			\
-			return -EINVAL;					\
-									\
-		if (burst < 0)						\
-			burst = 0;					\
-									\
-		pdev->aer_info->ratelimit.burst = burst;		\
-									\
-		return count;						\
-	}								\
-	static DEVICE_ATTR_RW(name);
-
 #define aer_ratelimit_attrs(name)					\
-	aer_ratelimit_interval_attr(name##_ratelimit_interval_ms,	\
-				    name##_ratelimit)			\
-	aer_ratelimit_burst_attr(name##_ratelimit_burst,		\
-				 name##_ratelimit)
+	PCI_RATELIMIT_INTERVAL_ATTR(name##_ratelimit_interval_ms,	\
+				    aer_info->name##_ratelimit);	\
+	PCI_RATELIMIT_BURST_ATTR(name##_ratelimit_burst,		\
+				 aer_info->name##_ratelimit)
 
-aer_ratelimit_attrs(correctable)
-aer_ratelimit_attrs(nonfatal)
+aer_ratelimit_attrs(correctable);
+aer_ratelimit_attrs(nonfatal);
 
 static struct attribute *aer_attrs[] = {
 	&dev_attr_correctable_ratelimit_interval_ms.attr,
@@ -792,6 +725,8 @@ const struct attribute_group aer_attr_group = {
 	.is_visible = SYSFS_GROUP_VISIBLE(aer),
 };
 
+#endif /* CONFIG_SYSFS */
+
 static void pci_dev_aer_stats_incr(struct pci_dev *pdev,
 				   struct aer_err_info *info)
 {
-- 
2.43.0