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null_blk: Add rotational feature support

PATCH Applied Damien Le Moal 5 participants 5 messages Nov 26, 2024 – Nov 29, 2024 Block layer

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Damien Le Moal

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#0 lore raw

PATCH 1/1 null_blk: Add rotational feature support

To facilitate testing of kernel functions related to the rotational feature (BLK_FEAT_ROTATIONAL) of a block device (e.g. NVMe rotational bit support), add the rotational boolean configfs attribute and module parameter to the null_blk driver. If set, a null block device will report being a rotational device through it queue limits features with the BLK_FEAT_ROTATIONAL flag.

Signed-off-by Damien Le Moal <[email protected]>
---
 drivers/block/null_blk/main.c     | 13 ++++++++++++-
 drivers/block/null_blk/null_blk.h |  1 +
 2 files changed, 13 insertions(+), 1 deletion(-)
drivers/block/null_blk/main.c +12 -1
index 3c3d8d200abb..32bd232cceef 100644
@@ -266,6 +266,10 @@ static bool g_zone_full;
 module_param_named(zone_full, g_zone_full, bool, S_IRUGO);
 MODULE_PARM_DESC(zone_full, "Initialize the sequential write required zones of a zoned device to be full. Default: false");
 
+static bool g_rotational;
+module_param_named(rotational, g_rotational, bool, S_IRUGO);
+MODULE_PARM_DESC(rotational, "Set the rotational feature for the device. Default: false");
+
 static struct nullb_device *null_alloc_dev(void);
 static void null_free_dev(struct nullb_device *dev);
 static void null_del_dev(struct nullb *nullb);

@@ -468,6 +472,7 @@ NULLB_DEVICE_ATTR(no_sched, bool, NULL);
 NULLB_DEVICE_ATTR(shared_tags, bool, NULL);
 NULLB_DEVICE_ATTR(shared_tag_bitmap, bool, NULL);
 NULLB_DEVICE_ATTR(fua, bool, NULL);
+NULLB_DEVICE_ATTR(rotational, bool, NULL);
 
 static ssize_t nullb_device_power_show(struct config_item *item, char *page)
 {

@@ -621,6 +626,7 @@ static struct configfs_attribute *nullb_device_attrs[] = {
 	&nullb_device_attr_shared_tags,
 	&nullb_device_attr_shared_tag_bitmap,
 	&nullb_device_attr_fua,
+	&nullb_device_attr_rotational,
 	NULL,
 };
 

@@ -706,7 +712,8 @@ static ssize_t memb_group_features_show(struct config_item *item, char *page)
 			"shared_tags,size,submit_queues,use_per_node_hctx,"
 			"virt_boundary,zoned,zone_capacity,zone_max_active,"
 			"zone_max_open,zone_nr_conv,zone_offline,zone_readonly,"
-			"zone_size,zone_append_max_sectors,zone_full\n");
+			"zone_size,zone_append_max_sectors,zone_full,"
+			"rotational\n");
 }
 
 CONFIGFS_ATTR_RO(memb_group_, features);

@@ -793,6 +800,7 @@ static struct nullb_device *null_alloc_dev(void)
 	dev->shared_tags = g_shared_tags;
 	dev->shared_tag_bitmap = g_shared_tag_bitmap;
 	dev->fua = g_fua;
+	dev->rotational = g_rotational;
 
 	return dev;
 }

@@ -1938,6 +1946,9 @@ static int null_add_dev(struct nullb_device *dev)
 			lim.features |= BLK_FEAT_FUA;
 	}
 
+	if (dev->rotational)
+		lim.features |= BLK_FEAT_ROTATIONAL;
+
 	nullb->disk = blk_mq_alloc_disk(nullb->tag_set, &lim, nullb);
 	if (IS_ERR(nullb->disk)) {
 		rv = PTR_ERR(nullb->disk);
drivers/block/null_blk/null_blk.h +1 -0
index a7bb32f73ec3..6f9fe6171087 100644
@@ -107,6 +107,7 @@ struct nullb_device {
 	bool shared_tags; /* share tag set between devices for blk-mq */
 	bool shared_tag_bitmap; /* use hostwide shared tags */
 	bool fua; /* Support FUA */
+	bool rotational; /* Fake rotational device */
 };
 
 struct nullb {
Signature · 1 line
2.47.0
Reviewed-by on v1 1/1
#1 lore raw
Quoted 6 lines · Damien Le Moal

To facilitate testing of kernel functions related to the rotational feature (BLK_FEAT_ROTATIONAL) of a block device (e.g. NVMe rotational bit support), add the rotational boolean configfs attribute and module parameter to the null_blk driver. If set, a null block device will report being a rotational device through it queue limits features with the BLK_FEAT_ROTATIONAL flag.

Looks good:

Reviewed-by Christoph Hellwig <[email protected]>
Reviewed-by on v1 1/1
#3 lore raw
In reply to Damien Le Moal
Quoted 7 lines · Damien Le Moal

To facilitate testing of kernel functions related to the rotational feature (BLK_FEAT_ROTATIONAL) of a block device (e.g. NVMe rotational bit support), add the rotational boolean configfs attribute and module parameter to the null_blk driver. If set, a null block device will report being a rotational device through it queue limits features with the BLK_FEAT_ROTATIONAL flag.

Quoted 6 lines
Signed-off-by Damien Le Moal <[email protected]>
---
  drivers/block/null_blk/main.c     | 13 ++++++++++++-
  drivers/block/null_blk/null_blk.h |  1 +
  2 files changed, 13 insertions(+), 1 deletion(-)
Reviewed-by Hannes Reinecke <[email protected]>

Cheers,

Hannes

Signature · 4 lines
Dr. Hannes Reinecke                  Kernel Storage Architect
[email protected]                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich
maintainer Applied
#4 lore raw
In reply to Damien Le Moal
Quoted 8 lines · Damien Le Moal

To facilitate testing of kernel functions related to the rotational feature (BLK_FEAT_ROTATIONAL) of a block device (e.g. NVMe rotational bit support), add the rotational boolean configfs attribute and module parameter to the null_blk driver. If set, a null block device will report being a rotational device through it queue limits features with the BLK_FEAT_ROTATIONAL flag.

[...]

Applied, thanks!

[1/1] null_blk: Add rotational feature support

      commit: 1c42dabc051ee9b55db21bf66959c7884f3a243e

Best regards,

Signature · 1 line
Jens Axboe