Re: [PATCH V3 03/12] block: Add zoned block device information to request queue

[Christoph Hellwig]

> +struct blk_zoned {
> + unsigned intnr_zones;
> + unsigned long   *seq_zones;
> +};
> +
>  struct blk_zone_report_hdr {
>   unsigned intnr_zones;
>   u8  padding[60];
> @@ -492,6 +497,10 @@ struct request_queue {
>   struct blk_integrity integrity;
>  #endif   /* CONFIG_BLK_DEV_INTEGRITY */
>  
> +#ifdef CONFIG_BLK_DEV_ZONED
> + struct blk_zonedzoned;
> +#endif

I'd prefer to just add the two fields direct to struct request_queue
instead of the container structure.

> +static inline unsigned int blk_queue_nr_zones(struct request_queue *q)
> +{
> + return blk_queue_is_zoned(q) ? q->zoned.nr_zones : 0;
> +}

I don't think this is going to compile without CONFIG_BLK_DEV_ZONED,
we'd either need two versions of it, or just always add nr_zones to
the request queue.

With nr_zones always present we could then remove the first check,
too as it would always be initialized to zero.

Re: [PATCH V3 03/12] block: Add zoned block device information to request queue

[Bart Van Assche]

On Fri, 2017-09-15 at 19:06 +0900, Damien Le Moal wrote:
> @@ -492,6 +497,10 @@ struct request_queue {
>   struct blk_integrity integrity;
>  #endif   /* CONFIG_BLK_DEV_INTEGRITY */
>  
> +#ifdef CONFIG_BLK_DEV_ZONED
> + struct blk_zonedzoned;
> +#endif
> +
>  #ifdef CONFIG_PM
>   struct device   *dev;
>   int rpm_status;
> @@ -785,6 +794,11 @@ static inline unsigned int blk_queue_zone_sectors(struct 
> request_queue *q)
>   return blk_queue_is_zoned(q) ? q->limits.chunk_sectors : 0;
>  }
>  
> +static inline unsigned int blk_queue_nr_zones(struct request_queue *q)
> +{
> + return blk_queue_is_zoned(q) ? q->zoned.nr_zones : 0;
> +}

Does this code compile correctly if CONFIG_BLK_DEV_ZONED is disabled? Should
the definition of blk_queue_nr_zones() perhaps be surrounded by #ifdef
CONFIG_BLK_DEV_ZONED / #endif?

Thanks,

Bart.

[PATCH V3 03/12] block: Add zoned block device information to request queue

[Damien Le Moal]

Components relying only on the requeuest_queue structure for managing
and controlling block devices (e.g. I/O schedulers) have a limited
view/knowledged of the device being controlled. For instance, the device
capacity cannot be known easily, which for a zoned block device also
result in the inability to know the number of zones of the device.

Define the structure blk_zoned and include it as the zoned field of a
request queue to allow low level drivers to provide more information
on the device.

Signed-off-by: Damien Le Moal 
---
 include/linux/blkdev.h | 24 
 1 file changed, 24 insertions(+)

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 460294bb0fa5..297e0a2fee31 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -349,6 +349,11 @@ struct queue_limits {
 
 #ifdef CONFIG_BLK_DEV_ZONED
 
+struct blk_zoned {
+   unsigned intnr_zones;
+   unsigned long   *seq_zones;
+};
+
 struct blk_zone_report_hdr {
unsigned intnr_zones;
u8  padding[60];
@@ -492,6 +497,10 @@ struct request_queue {
struct blk_integrity integrity;
 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 
+#ifdef CONFIG_BLK_DEV_ZONED
+   struct blk_zonedzoned;
+#endif
+
 #ifdef CONFIG_PM
struct device   *dev;
int rpm_status;
@@ -785,6 +794,11 @@ static inline unsigned int blk_queue_zone_sectors(struct 
request_queue *q)
return blk_queue_is_zoned(q) ? q->limits.chunk_sectors : 0;
 }
 
+static inline unsigned int blk_queue_nr_zones(struct request_queue *q)
+{
+   return blk_queue_is_zoned(q) ? q->zoned.nr_zones : 0;
+}
+
 static inline bool rq_is_sync(struct request *rq)
 {
return op_is_sync(rq->cmd_flags);
@@ -1582,6 +1596,16 @@ static inline unsigned int bdev_zone_sectors(struct 
block_device *bdev)
return 0;
 }
 
+static inline unsigned int bdev_nr_zones(struct block_device *bdev)
+{
+   struct request_queue *q = bdev_get_queue(bdev);
+
+   if (q)
+   return blk_queue_nr_zones(q);
+
+   return 0;
+}
+
 static inline int queue_dma_alignment(struct request_queue *q)
 {
return q ? q->dma_alignment : 511;
-- 
2.13.5