[PATCH V3 1/3] block: add a zone condition debug helper

[Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>]

Add a helper to stringify the zone conditions. We use this helper in the
next patch to track zone conditions in tracepoints.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
 block/blk-zoned.c      | 32 ++++++++++++++++++++++++++++++++
 include/linux/blkdev.h |  3 +++
 2 files changed, 35 insertions(+)

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 6b442ae96499..f87956e0dcaf 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -20,6 +20,38 @@
 
 #include "blk.h"
 
+#define ZONE_COND_NAME(name) [BLK_ZONE_COND_##name] = #name
+static const char *const zone_cond_name[] = {
+	ZONE_COND_NAME(NOT_WP),
+	ZONE_COND_NAME(EMPTY),
+	ZONE_COND_NAME(IMP_OPEN),
+	ZONE_COND_NAME(EXP_OPEN),
+	ZONE_COND_NAME(CLOSED),
+	ZONE_COND_NAME(READONLY),
+	ZONE_COND_NAME(FULL),
+	ZONE_COND_NAME(OFFLINE),
+};
+#undef ZONE_COND_NAME
+
+/**
+ * blk_zone_cond_str - Return string XXX in BLK_ZONE_COND_XXX.
+ * @zone_cond: BLK_ZONE_COND_XXX.
+ *
+ * Description: Centralize block layer function to convert BLK_ZONE_COND_XXX
+ * into string format. Useful in the debugging and tracing zone conditions. For
+ * invalid BLK_ZONE_COND_XXX it returns string "UNKNOWN".
+ */
+const char *blk_zone_cond_str(enum blk_zone_cond zone_cond)
+{
+	static const char *zone_cond_str = "UNKNOWN";
+
+	if (zone_cond < ARRAY_SIZE(zone_cond_name) && zone_cond_name[zone_cond])
+		zone_cond_str = zone_cond_name[zone_cond];
+
+	return zone_cond_str;
+}
+EXPORT_SYMBOL_GPL(blk_zone_cond_str);
+
 static inline sector_t blk_zone_start(struct request_queue *q,
 				      sector_t sector)
 {
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 53a1325efbc3..0070f26b9579 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -887,6 +887,9 @@ extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
 /* Helper to convert REQ_OP_XXX to its string format XXX */
 extern const char *blk_op_str(unsigned int op);
 
+/* Helper to convert BLK_ZONE_ZONE_XXX to its string format XXX */
+extern const char *blk_zone_cond_str(enum blk_zone_cond zone_cond);
+
 int blk_status_to_errno(blk_status_t status);
 blk_status_t errno_to_blk_status(int errno);
 
-- 
2.22.0