blk-mq: export hctx->type in debugfs instead of sysfs

Now we only export hctx->type via sysfs, and there isn't such info
in hctx entry under debugfs. We often use debugfs only to diagnose
queue mapping issue, so add the support in debugfs.

Queue mapping becomes a bit more complicated after multiple queue
mapping is supported, we may write blktest to verify if queue mapping
is valid based on blk-mq-debugfs.

Given not necessary to export hctx->type twice, so remove the export
from sysfs.

Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-mq-debugfs.c

@@ -447,6 +447,21 @@ static int hctx_busy_show(void *data, struct seq_file *m)
 	return 0;
 }
 
+static const char *const hctx_types[] = {
+	[HCTX_TYPE_DEFAULT]	= "default",
+	[HCTX_TYPE_READ]	= "read",
+	[HCTX_TYPE_POLL]	= "poll",
+};
+
+static int hctx_type_show(void *data, struct seq_file *m)
+{
+	struct blk_mq_hw_ctx *hctx = data;
+
+	BUILD_BUG_ON(ARRAY_SIZE(hctx_types) != HCTX_MAX_TYPES);
+	seq_printf(m, "%s\n", hctx_types[hctx->type]);
+	return 0;
+}
+
 static int hctx_ctx_map_show(void *data, struct seq_file *m)
 {
 	struct blk_mq_hw_ctx *hctx = data;
@@ -799,6 +814,7 @@ static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {
 	{"run", 0600, hctx_run_show, hctx_run_write},
 	{"active", 0400, hctx_active_show},
 	{"dispatch_busy", 0400, hctx_dispatch_busy_show},
+	{"type", 0400, hctx_type_show},
 	{},
 };
 

block/blk-mq-sysfs.c

@@ -173,18 +173,6 @@ static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page)
 	return ret;
 }
 
-static const char *const hctx_types[] = {
-	[HCTX_TYPE_DEFAULT]	= "default",
-	[HCTX_TYPE_READ]	= "read",
-	[HCTX_TYPE_POLL]	= "poll",
-};
-
-static ssize_t blk_mq_hw_sysfs_type_show(struct blk_mq_hw_ctx *hctx, char *page)
-{
-	BUILD_BUG_ON(ARRAY_SIZE(hctx_types) != HCTX_MAX_TYPES);
-	return sprintf(page, "%s\n", hctx_types[hctx->type]);
-}
-
 static struct attribute *default_ctx_attrs[] = {
 	NULL,
 };
@@ -201,16 +189,11 @@ static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_cpus = {
 	.attr = {.name = "cpu_list", .mode = 0444 },
 	.show = blk_mq_hw_sysfs_cpus_show,
 };
-static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_type = {
-	.attr = {.name = "type", .mode = 0444 },
-	.show = blk_mq_hw_sysfs_type_show,
-};
 
 static struct attribute *default_hw_ctx_attrs[] = {
 	&blk_mq_hw_sysfs_nr_tags.attr,
 	&blk_mq_hw_sysfs_nr_reserved_tags.attr,
 	&blk_mq_hw_sysfs_cpus.attr,
-	&blk_mq_hw_sysfs_type.attr,
 	NULL,
 };