[PATCH for-rc 03/24] block/rnbd: Enable the fault-injection

[Gioh Kim <gi-oh.kim@ionos.com>]

From: Gioh Kim <gi-oh.kim@cloud.ionos.com>

This patch introduces functions to enable the fault-injection for RTRS.
* rnbd_fault_inject_init/final: initialize the fault-injection
and create a debugfs directory.
* rnbd_fault_inject_add: create a debugfs entry to enable
the fault-injection point.

Signed-off-by: Gioh Kim <gi-oh.kim@cloud.ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
---
 drivers/block/rnbd/rnbd-common.c | 44 ++++++++++++++++++++++++++++++++
 drivers/block/rnbd/rnbd-proto.h  | 14 ++++++++++
 2 files changed, 58 insertions(+)

diff --git a/drivers/block/rnbd/rnbd-common.c b/drivers/block/rnbd/rnbd-common.c
index 596c3f732403..84bfbf015f6d 100644
--- a/drivers/block/rnbd/rnbd-common.c
+++ b/drivers/block/rnbd/rnbd-common.c
@@ -21,3 +21,47 @@ const char *rnbd_access_mode_str(enum rnbd_access_mode mode)
 		return "unknown";
 	}
 }
+
+#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
+static DECLARE_FAULT_ATTR(fail_default_attr);
+
+void rnbd_fault_inject_init(struct rnbd_fault_inject *fj,
+			    const char *dir_name,
+			    u32 err_status)
+{
+	struct dentry *dir, *parent;
+	struct fault_attr *attr = &fj->attr;
+
+	/* create debugfs directory and attribute */
+	parent = debugfs_create_dir(dir_name, NULL);
+	if (!parent) {
+		pr_warn("%s: failed to create debugfs directory\n", dir_name);
+		return;
+	}
+
+	*attr = fail_default_attr;
+	dir = fault_create_debugfs_attr("fault_inject", parent, attr);
+	if (IS_ERR(dir)) {
+		pr_warn("%s: failed to create debugfs attr\n", dir_name);
+		debugfs_remove_recursive(parent);
+		return;
+	}
+	fj->parent = parent;
+	fj->dir = dir;
+
+	/* create debugfs for status code */
+	fj->status = err_status;
+	debugfs_create_u32("status", 0600, dir,	&fj->status);
+}
+
+void rnbd_fault_inject_add(struct dentry *dir, const char *fname, bool *value)
+{
+	debugfs_create_bool(fname, 0600, dir, value);
+}
+
+void rnbd_fault_inject_final(struct rnbd_fault_inject *fj)
+{
+	/* remove debugfs directories */
+	debugfs_remove_recursive(fj->parent);
+}
+#endif
diff --git a/drivers/block/rnbd/rnbd-proto.h b/drivers/block/rnbd/rnbd-proto.h
index c1bc5c0fef71..d13dc1d3a00e 100644
--- a/drivers/block/rnbd/rnbd-proto.h
+++ b/drivers/block/rnbd/rnbd-proto.h
@@ -15,6 +15,7 @@
 #include <linux/inet.h>
 #include <linux/in.h>
 #include <linux/in6.h>
+#include <linux/fault-inject.h>
 #include <rdma/ib.h>
 
 #define RNBD_PROTO_VER_MAJOR 2
@@ -305,6 +306,19 @@ static inline u32 rq_to_rnbd_flags(struct request *rq)
 	return rnbd_opf;
 }
 
+struct rnbd_fault_inject {
+#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
+	struct fault_attr attr;
+	struct dentry *parent;
+	struct dentry *dir;
+	u32 status;
+#endif
+};
+
 const char *rnbd_access_mode_str(enum rnbd_access_mode mode);
 
+void rnbd_fault_inject_init(struct rnbd_fault_inject *fj,
+			    const char *dev_name, u32 err_status);
+void rnbd_fault_inject_add(struct dentry *dir, const char *fname, bool *value);
+void rnbd_fault_inject_final(struct rnbd_fault_inject *fj);
 #endif /* RNBD_PROTO_H */
-- 
2.25.1