devcoredump: Add dev_coredump_put()

It is useful for modules that do not want to keep coredump available
after its unload.
Otherwise, the coredump would only be removed after DEVCD_TIMEOUT
seconds.

v2:
- dev_coredump_put() documentation updated (Mukesh)

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Mukesh Ojha <quic_mojha@quicinc.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Jonathan Cavitt <jonathan.cavitt@intel.com>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240409200206.108452-1-jose.souza@intel.comSigned-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/base/devcoredump.c

@@ -304,6 +304,29 @@ static ssize_t devcd_read_from_sgtable(char *buffer, loff_t offset,
 				  offset);
 }
 
+/**
+ * dev_coredump_put - remove device coredump
+ * @dev: the struct device for the crashed device
+ *
+ * dev_coredump_put() removes coredump, if exists, for a given device from
+ * the file system and free its associated data otherwise, does nothing.
+ *
+ * It is useful for modules that do not want to keep coredump
+ * available after its unload.
+ */
+void dev_coredump_put(struct device *dev)
+{
+	struct device *existing;
+
+	existing = class_find_device(&devcd_class, NULL, dev,
+				     devcd_match_failing);
+	if (existing) {
+		devcd_free(existing, NULL);
+		put_device(existing);
+	}
+}
+EXPORT_SYMBOL_GPL(dev_coredump_put);
+
 /**
  * dev_coredumpm - create device coredump with read/free methods
  * @dev: the struct device for the crashed device

include/linux/devcoredump.h

@@ -63,6 +63,8 @@ void dev_coredumpm(struct device *dev, struct module *owner,
 
 void dev_coredumpsg(struct device *dev, struct scatterlist *table,
 		    size_t datalen, gfp_t gfp);
+
+void dev_coredump_put(struct device *dev);
 #else
 static inline void dev_coredumpv(struct device *dev, void *data,
 				 size_t datalen, gfp_t gfp)
@@ -85,6 +87,9 @@ static inline void dev_coredumpsg(struct device *dev, struct scatterlist *table,
 {
 	_devcd_free_sgtable(table);
 }
+static inline void dev_coredump_put(struct device *dev)
+{
+}
 #endif /* CONFIG_DEV_COREDUMP */
 
 #endif /* __DEVCOREDUMP_H */