[1/9] block: Add 'zoned' queue limit

Commit Message

Damien Le Moal Sept. 19, 2016, 9:27 p.m. UTC

Add the zoned queue limit to indicate the zoning model of a block
device. Defined values are 0 (BLK_ZONED_NONE) for regular block
devices, 1 (BLK_ZONED_HA) for host-aware zone block devices and 2
(BLK_ZONED_HM) for host-managed zone block devices. The drive managed
model is not defined here since these block devices do not provide any
command for accessing zone information. The helper functions
blk_queue_zoned and bdev_zoned return the zoned limit which can in turn
be used as a boolean to test if a block device is zoned.

The zoned attribute is also exported as a string to applications via
sysfs. BLK_ZONED_NONE shows as "none", BLK_ZONED_HA as "host-aware" and
BLK_ZONED_HM as "host-managed".

Signed-off-by: Damien Le Moal <[e-mail]>
---
 block/blk-settings.c   |  1 +
 block/blk-sysfs.c      | 18 ++++++++++++++++++
 include/linux/blkdev.h | 25 +++++++++++++++++++++++++
 3 files changed, 44 insertions(+)

Comments

Bart Van Assche Sept. 20, 2016, 4:05 a.m. UTC | #1

On 09/19/16 14:27, Damien Le Moal wrote:
> +/*
> + * Zoned block device models (zoned limit).
> + */
> +enum blk_zoned_model {
> +	BLK_ZONED_NONE,	/* Regular block device */
> +	BLK_ZONED_HA, 	/* Host-aware zoned block device */
> +	BLK_ZONED_HM,	/* Host-managed zoned block device */
> +};

[ ... ]

> +static inline unsigned int blk_queue_zoned(struct request_queue *q)
> +{
> +	return q->limits.zoned;
> +}
> +
>  /*
>   * We regard a request as sync, if either a read or a sync write
>   */
> @@ -1354,6 +1369,16 @@ static inline unsigned int bdev_write_same(struct block_device *bdev)
>  	return 0;
>  }
>
> +static inline unsigned int bdev_zoned(struct block_device *bdev)
> +{
> +	struct request_queue *q = bdev_get_queue(bdev);
> +
> +	if (q)
> +		return blk_queue_zoned(q);
> +
> +	return 0;
> +}

Hello Damien,

Please consider changing the return type of the above two functions into 
"enum blk_zoned_model" to make it clear that both return one of the 
BLK_ZONED_* constants.

Thanks,

Bart.
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Patch

diff --git a/block/blk-settings.c b/block/blk-settings.c
index f679ae1..b1d5b7f 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -107,6 +107,7 @@  void blk_set_default_limits(struct queue_limits *lim)
 	lim->io_opt = 0;
 	lim->misaligned = 0;
 	lim->cluster = 1;
+	lim->zoned = BLK_ZONED_NONE;
 }
 EXPORT_SYMBOL(blk_set_default_limits);
 
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index f87a7e7..31ecff9 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -257,6 +257,18 @@  QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0);
 QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0);
 #undef QUEUE_SYSFS_BIT_FNS
 
+static ssize_t queue_zoned_show(struct request_queue *q, char *page)
+{
+	switch (blk_queue_zoned(q)) {
+	case BLK_ZONED_HA:
+		return sprintf(page, "host-aware\n");
+	case BLK_ZONED_HM:
+		return sprintf(page, "host-managed\n");
+	default:
+		return sprintf(page, "none\n");
+	}
+}
+
 static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
 {
 	return queue_var_show((blk_queue_nomerges(q) << 1) |
@@ -485,6 +497,11 @@  static struct queue_sysfs_entry queue_nonrot_entry = {
 	.store = queue_store_nonrot,
 };
 
+static struct queue_sysfs_entry queue_zoned_entry = {
+	.attr = {.name = "zoned", .mode = S_IRUGO },
+	.show = queue_zoned_show,
+};
+
 static struct queue_sysfs_entry queue_nomerges_entry = {
 	.attr = {.name = "nomerges", .mode = S_IRUGO | S_IWUSR },
 	.show = queue_nomerges_show,
@@ -546,6 +563,7 @@  static struct attribute *default_attrs[] = {
 	&queue_discard_zeroes_data_entry.attr,
 	&queue_write_same_max_entry.attr,
 	&queue_nonrot_entry.attr,
+	&queue_zoned_entry.attr,
 	&queue_nomerges_entry.attr,
 	&queue_rq_affinity_entry.attr,
 	&queue_iostats_entry.attr,
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index e79055c..1c74b19 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -261,6 +261,15 @@  struct blk_queue_tag {
 #define BLK_SCSI_MAX_CMDS	(256)
 #define BLK_SCSI_CMD_PER_LONG	(BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
 
+/*
+ * Zoned block device models (zoned limit).
+ */
+enum blk_zoned_model {
+	BLK_ZONED_NONE,	/* Regular block device */
+	BLK_ZONED_HA, 	/* Host-aware zoned block device */
+	BLK_ZONED_HM,	/* Host-managed zoned block device */
+};
+
 struct queue_limits {
 	unsigned long		bounce_pfn;
 	unsigned long		seg_boundary_mask;
@@ -290,6 +299,7 @@  struct queue_limits {
 	unsigned char		cluster;
 	unsigned char		discard_zeroes_data;
 	unsigned char		raid_partial_stripes_expensive;
+	unsigned char		zoned;
 };
 
 struct request_queue {
@@ -627,6 +637,11 @@  static inline unsigned int blk_queue_cluster(struct request_queue *q)
 	return q->limits.cluster;
 }
 
+static inline unsigned int blk_queue_zoned(struct request_queue *q)
+{
+	return q->limits.zoned;
+}
+
 /*
  * We regard a request as sync, if either a read or a sync write
  */
@@ -1354,6 +1369,16 @@  static inline unsigned int bdev_write_same(struct block_device *bdev)
 	return 0;
 }
 
+static inline unsigned int bdev_zoned(struct block_device *bdev)
+{
+	struct request_queue *q = bdev_get_queue(bdev);
+
+	if (q)
+		return blk_queue_zoned(q);
+
+	return 0;
+}
+
 static inline int queue_dma_alignment(struct request_queue *q)
 {
 	return q ? q->dma_alignment : 511;