[PATCH v2 02/10] block: Introduce queue limits for copy-offload support

[Nitesh Shetty]

Add device limits as sysfs entries,
        - copy_offload (READ_WRITE)
        - max_copy_sectors (READ_ONLY)
        - max_copy_ranges_sectors (READ_ONLY)
        - max_copy_nr_ranges (READ_ONLY)

copy_offload(= 0), is disabled by default. This needs to be enabled if
copy-offload needs to be used.
max_copy_sectors = 0, indicates the device doesn't support native copy.

Signed-off-by: Nitesh Shetty <nj.shetty at samsung.com>
Signed-off-by: SelvaKumar S <selvakuma.s1 at samsung.com>
Signed-off-by: Kanchan Joshi <joshi.k at samsung.com>
---
 block/blk-settings.c   |  4 ++++
 block/blk-sysfs.c      | 51 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/blkdev.h | 12 ++++++++++
 3 files changed, 67 insertions(+)

diff --git a/block/blk-settings.c b/block/blk-settings.c
index b880c70e22e4..818454552cf8 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -57,6 +57,10 @@ void blk_set_default_limits(struct queue_limits *lim)
 	lim->misaligned = 0;
 	lim->zoned = BLK_ZONED_NONE;
 	lim->zone_write_granularity = 0;
+	lim->copy_offload = 0;
+	lim->max_copy_sectors = 0;
+	lim->max_copy_nr_ranges = 0;
+	lim->max_copy_range_sectors = 0;
 }
 EXPORT_SYMBOL(blk_set_default_limits);
 
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 9f32882ceb2f..dc68ae6b55c9 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -171,6 +171,48 @@ static ssize_t queue_discard_granularity_show(struct request_queue *q, char *pag
 	return queue_var_show(q->limits.discard_granularity, page);
 }
 
+static ssize_t queue_copy_offload_show(struct request_queue *q, char *page)
+{
+	return queue_var_show(q->limits.copy_offload, page);
+}
+
+static ssize_t queue_copy_offload_store(struct request_queue *q,
+				       const char *page, size_t count)
+{
+	unsigned long copy_offload;
+	ssize_t ret = queue_var_store(&copy_offload, page, count);
+
+	if (ret < 0)
+		return ret;
+
+	if (copy_offload && q->limits.max_copy_sectors == 0)
+		return -EINVAL;
+
+	if (copy_offload)
+		q->limits.copy_offload = BLK_COPY_OFFLOAD;
+	else
+		q->limits.copy_offload = 0;
+
+	return ret;
+}
+
+static ssize_t queue_max_copy_sectors_show(struct request_queue *q, char *page)
+{
+	return queue_var_show(q->limits.max_copy_sectors, page);
+}
+
+static ssize_t queue_max_copy_range_sectors_show(struct request_queue *q,
+		char *page)
+{
+	return queue_var_show(q->limits.max_copy_range_sectors, page);
+}
+
+static ssize_t queue_max_copy_nr_ranges_show(struct request_queue *q,
+		char *page)
+{
+	return queue_var_show(q->limits.max_copy_nr_ranges, page);
+}
+
 static ssize_t queue_discard_max_hw_show(struct request_queue *q, char *page)
 {
 
@@ -597,6 +639,11 @@ QUEUE_RO_ENTRY(queue_nr_zones, "nr_zones");
 QUEUE_RO_ENTRY(queue_max_open_zones, "max_open_zones");
 QUEUE_RO_ENTRY(queue_max_active_zones, "max_active_zones");
 
+QUEUE_RW_ENTRY(queue_copy_offload, "copy_offload");
+QUEUE_RO_ENTRY(queue_max_copy_sectors, "max_copy_sectors");
+QUEUE_RO_ENTRY(queue_max_copy_range_sectors, "max_copy_range_sectors");
+QUEUE_RO_ENTRY(queue_max_copy_nr_ranges, "max_copy_nr_ranges");
+
 QUEUE_RW_ENTRY(queue_nomerges, "nomerges");
 QUEUE_RW_ENTRY(queue_rq_affinity, "rq_affinity");
 QUEUE_RW_ENTRY(queue_poll, "io_poll");
@@ -643,6 +690,10 @@ static struct attribute *queue_attrs[] = {
 	&queue_discard_max_entry.attr,
 	&queue_discard_max_hw_entry.attr,
 	&queue_discard_zeroes_data_entry.attr,
+	&queue_copy_offload_entry.attr,
+	&queue_max_copy_sectors_entry.attr,
+	&queue_max_copy_range_sectors_entry.attr,
+	&queue_max_copy_nr_ranges_entry.attr,
 	&queue_write_same_max_entry.attr,
 	&queue_write_zeroes_max_entry.attr,
 	&queue_zone_append_max_entry.attr,
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index efed3820cbf7..f63ae50f1de3 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -51,6 +51,12 @@ extern struct class block_class;
 /* Doing classic polling */
 #define BLK_MQ_POLL_CLASSIC -1
 
+/* Define copy offload options */
+enum blk_copy {
+	BLK_COPY_EMULATE = 0,
+	BLK_COPY_OFFLOAD,
+};
+
 /*
  * Maximum number of blkcg policies allowed to be registered concurrently.
  * Defined here to simplify include dependency.
@@ -253,6 +259,10 @@ struct queue_limits {
 	unsigned int		discard_granularity;
 	unsigned int		discard_alignment;
 	unsigned int		zone_write_granularity;
+	unsigned int            copy_offload;
+	unsigned int            max_copy_sectors;
+	unsigned short          max_copy_range_sectors;
+	unsigned short          max_copy_nr_ranges;
 
 	unsigned short		max_segments;
 	unsigned short		max_integrity_segments;
@@ -562,6 +572,7 @@ struct request_queue {
 #define QUEUE_FLAG_RQ_ALLOC_TIME 27	/* record rq->alloc_time_ns */
 #define QUEUE_FLAG_HCTX_ACTIVE	28	/* at least one blk-mq hctx is active */
 #define QUEUE_FLAG_NOWAIT       29	/* device supports NOWAIT */
+#define QUEUE_FLAG_COPY		30	/* supports copy offload */
 
 #define QUEUE_FLAG_MQ_DEFAULT	((1 << QUEUE_FLAG_IO_STAT) |		\
 				 (1 << QUEUE_FLAG_SAME_COMP) |		\
@@ -585,6 +596,7 @@ bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q);
 #define blk_queue_io_stat(q)	test_bit(QUEUE_FLAG_IO_STAT, &(q)->queue_flags)
 #define blk_queue_add_random(q)	test_bit(QUEUE_FLAG_ADD_RANDOM, &(q)->queue_flags)
 #define blk_queue_discard(q)	test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
+#define blk_queue_copy(q)	test_bit(QUEUE_FLAG_COPY, &(q)->queue_flags)
 #define blk_queue_zone_resetall(q)	\
 	test_bit(QUEUE_FLAG_ZONE_RESETALL, &(q)->queue_flags)
 #define blk_queue_secure_erase(q) \
-- 
2.30.0-rc0