Block storage copy offloading

Documentation/ABI/stable/sysfs-block

@@ -239,6 +239,30 @@ Description:
 		last zone of the device which may be smaller.
 
 
+What:		/sys/block/<disk>/queue/copy_max_bytes
+Date:		May 2026
+Contact:	linux-block@vger.kernel.org
+Description:
+		[RW] This is the maximum number of bytes that the block layer
+		will allow for a copy request. This is always smaller or
+		equal to the maximum size allowed by the block driver.
+		Any value higher than 'copy_max_hw_bytes' will be reduced to
+		'copy_max_hw_bytes'. Writing '0' to this attribute will disable
+		copy offloading for this block device. If copy offloading is
+		disabled, copy requests will be translated into read and write
+		requests.
+
+
+What:		/sys/block/<disk>/queue/copy_max_hw_bytes
+Date:		May 2026
+Contact:	linux-block@vger.kernel.org
+Description:
+		[RO] This is the maximum number of bytes that is allowed for
+		a single data copy request. Set by the block driver. The value
+		zero indicates that the block device does not support copy
+		offloading.
+
+
 What:		/sys/block/<disk>/queue/crypto/
 Date:		February 2022
 Contact:	linux-block@vger.kernel.org

Documentation/block/null_blk.rst

@@ -149,3 +149,7 @@ zone_size=[MB]: Default: 256
 zone_nr_conv=[nr_conv]: Default: 0
   The number of conventional zones to create when block device is zoned.  If
   zone_nr_conv >= nr_zones, it will be reduced to nr_zones - 1.
+
+max_copy_bytes=[size in bytes]: Default: UINT_MAX
+  A module and configfs parameter which can be used to set hardware/driver
+  supported maximum copy offload limit.

block/Makefile

@@ -6,7 +6,7 @@
 obj-y		:= bdev.o fops.o bio.o elevator.o blk-core.o blk-sysfs.o \
 			blk-flush.o blk-settings.o blk-ioc.o blk-map.o \
 			blk-merge.o blk-timeout.o blk-lib.o blk-mq.o \
-			blk-mq-tag.o blk-mq-dma.o blk-stat.o \
+			blk-mq-tag.o blk-mq-dma.o blk-stat.o blk-copy.o \
 			blk-mq-sysfs.o blk-mq-cpumap.o blk-mq-sched.o ioctl.o \
 			genhd.o ioprio.o badblocks.o partitions/ blk-rq-qos.o \
 			disk-events.o blk-ia-ranges.o early-lookup.o

block/bio.c

@@ -852,6 +852,7 @@ static int __bio_clone(struct bio *bio, struct bio *bio_src, gfp_t gfp)
 	bio->bi_write_hint = bio_src->bi_write_hint;
 	bio->bi_write_stream = bio_src->bi_write_stream;
 	bio->bi_iter = bio_src->bi_iter;
+	bio->bi_copy_ctx = bio_src->bi_copy_ctx;
 
 	if (bio->bi_bdev) {
 		if (bio->bi_bdev == bio_src->bi_bdev &&