block: add a "tag" for block status codes

The full name of the status codes is not good for user interfaces as it
can contain white spaces.  Add the name of the status code without the
BLK_STS_ prefix as a tag so that it can be used for user interfaces.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@kernel.org>
Reviewed-by: Md Haris Iqbal <haris.iqbal@linux.dev>
Link: https://patch.msgid.link/20260611140703.2401204-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Christoph Hellwig

block/blk-core.c

@@ -135,10 +135,12 @@ EXPORT_SYMBOL_GPL(blk_op_str);
 #define ENT(_tag, _errno, _desc)	\
 [BLK_STS_##_tag] = {				\
 	.errno		= _errno,		\
+	.tag		= __stringify(_tag),	\
 	.name		= _desc,		\
 }
 static const struct {
 	int		errno;
+	const char	*tag;
 	const char	*name;
 } blk_errors[] = {
 	ENT(OK,			0,		""),
@@ -203,6 +205,32 @@ const char *blk_status_to_str(blk_status_t status)
 	return blk_errors[idx].name;
 }
 
+const char *blk_status_to_tag(blk_status_t status)
+{
+	int idx = (__force int)status;
+
+	if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors) || !blk_errors[idx].tag))
+		return "<null>";
+	return blk_errors[idx].tag;
+}
+
+blk_status_t tag_to_blk_status(const char *tag)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(blk_errors); i++) {
+		if (blk_errors[i].tag &&
+		    !strcmp(blk_errors[i].tag, tag))
+			return (__force blk_status_t)i;
+	}
+
+	/*
+	 * Return BLK_STS_OK for mismatches as this function is intended to
+	 * parse error status values.
+	 */
+	return BLK_STS_OK;
+}
+
 /**
  * blk_sync_queue - cancel any pending callbacks on a queue
  * @q: the queue

block/blk.h

@@ -51,6 +51,8 @@ struct blk_flush_queue *blk_alloc_flush_queue(int node, int cmd_size,
 void blk_free_flush_queue(struct blk_flush_queue *q);
 
 const char *blk_status_to_str(blk_status_t status);
+const char *blk_status_to_tag(blk_status_t status);
+blk_status_t tag_to_blk_status(const char *tag);
 
 bool __blk_mq_unfreeze_queue(struct request_queue *q, bool force_atomic);
 bool blk_queue_start_drain(struct request_queue *q);