libie: depend on DEBUG_FS when building LIBIE_FWLOG

LIBIE_FWLOG is unusable without DEBUG_FS. Mark it in Kconfig.

Fix build error on ixgbe when DEBUG_FS is not set. To not add another
layer of #if IS_ENABLED(LIBIE_FWLOG) in ixgbe fwlog code define debugfs
dentry even when DEBUG_FS isn't enabled. In this case the dummy
functions of LIBIE_FWLOG will be used, so not initialized dentry isn't a
problem.

Fixes: 641585b ("ixgbe: fwlog support for e610")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Closes: https://lore.kernel.org/lkml/f594c621-f9e1-49f2-af31-23fbcb176058@roeck-us.net/
Signed-off-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Tested-by: Rinitha S <sx.rinitha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Link: https://patch.msgid.link/20251104172333.752445-1-anthony.l.nguyen@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: Michal Swiatkowski

drivers/net/ethernet/intel/Kconfig

@@ -146,7 +146,7 @@ config IXGBE
 	tristate "Intel(R) 10GbE PCI Express adapters support"
 	depends on PCI
 	depends on PTP_1588_CLOCK_OPTIONAL
-	select LIBIE_FWLOG
+	select LIBIE_FWLOG if DEBUG_FS
 	select MDIO
 	select NET_DEVLINK
 	select PLDMFW
@@ -298,7 +298,7 @@ config ICE
 	select DIMLIB
 	select LIBIE
 	select LIBIE_ADMINQ
-	select LIBIE_FWLOG
+	select LIBIE_FWLOG if DEBUG_FS
 	select NET_DEVLINK
 	select PACKING
 	select PLDMFW

drivers/net/ethernet/intel/ixgbe/ixgbe.h

@@ -821,9 +821,7 @@ struct ixgbe_adapter {
 #ifdef CONFIG_IXGBE_HWMON
 	struct hwmon_buff *ixgbe_hwmon_buff;
 #endif /* CONFIG_IXGBE_HWMON */
-#ifdef CONFIG_DEBUG_FS
 	struct dentry *ixgbe_dbg_adapter;
-#endif /*CONFIG_DEBUG_FS*/
 
 	u8 default_up;
 	/* Bitmask indicating in use pools */

include/linux/net/intel/libie/fwlog.h

@@ -78,8 +78,20 @@ struct libie_fwlog {
 	);
 };
 
+#if IS_ENABLED(CONFIG_LIBIE_FWLOG)
 int libie_fwlog_init(struct libie_fwlog *fwlog, struct libie_fwlog_api *api);
 void libie_fwlog_deinit(struct libie_fwlog *fwlog);
 void libie_fwlog_reregister(struct libie_fwlog *fwlog);
 void libie_get_fwlog_data(struct libie_fwlog *fwlog, u8 *buf, u16 len);
+#else
+static inline int libie_fwlog_init(struct libie_fwlog *fwlog,
+				   struct libie_fwlog_api *api)
+{
+	return -EOPNOTSUPP;
+}
+static inline void libie_fwlog_deinit(struct libie_fwlog *fwlog) { }
+static inline void libie_fwlog_reregister(struct libie_fwlog *fwlog) { }
+static inline void libie_get_fwlog_data(struct libie_fwlog *fwlog, u8 *buf,
+					u16 len) { }
+#endif /* CONFIG_LIBIE_FWLOG */
 #endif /* _LIBIE_FWLOG_H_ */