This patch implements basic copy support for device mapper core.
Individual targets can enable copy support by setting ti->copy_supported.
Device mapper device advertises copy support if at least one target
supports copy and for this target, at least one underlying device supports
copy.
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
---
drivers/md/dm-table.c | 16 ++++++++++++++++
drivers/md/dm.c | 27 +++++++++++++++++++++++++++
include/linux/device-mapper.h | 5 +++++
3 files changed, 48 insertions(+)
Index: linux-4.4-rc4/drivers/md/dm.c
===================================================================
--- linux-4.4-rc4.orig/drivers/md/dm.c 2015-12-10 17:04:05.000000000 +0100
+++ linux-4.4-rc4/drivers/md/dm.c 2015-12-10 17:05:48.000000000 +0100
@@ -1679,6 +1679,31 @@ static int __send_write_same(struct clon
return __send_changing_extent_only(ci, get_num_write_same_bios, NULL);
}
+static int __send_copy(struct clone_info *ci)
+{
+ struct dm_target *ti;
+ sector_t bound;
+
+ ti = dm_table_find_target(ci->map, ci->sector);
+ if (!dm_target_is_valid(ti))
+ return -EIO;
+
+ if (!ti->copy_supported)
+ return -EOPNOTSUPP;
+
+ bound = max_io_len(ci->sector, ti);
+
+ if (unlikely(ci->sector_count > bound))
+ return -EOPNOTSUPP;
+
+ __clone_and_map_simple_bio(ci, ti, 0, NULL);
+
+ ci->sector += ci->sector_count;
+ ci->sector_count = 0;
+
+ return 0;
+}
+
/*
* Select the correct strategy for processing a non-flush bio.
*/
@@ -1692,6 +1717,8 @@ static int __split_and_process_non_flush
return __send_discard(ci);
else if (unlikely(bio->bi_rw & REQ_WRITE_SAME))
return __send_write_same(ci);
+ else if (unlikely(bio->bi_rw & REQ_COPY))
+ return __send_copy(ci);
ti = dm_table_find_target(ci->map, ci->sector);
if (!dm_target_is_valid(ti))
Index: linux-4.4-rc4/include/linux/device-mapper.h
===================================================================
--- linux-4.4-rc4.orig/include/linux/device-mapper.h 2015-12-10 17:04:05.000000000 +0100
+++ linux-4.4-rc4/include/linux/device-mapper.h 2015-12-10 17:04:59.000000000 +0100
@@ -271,6 +271,11 @@ struct dm_target {
* Set if this target does not return zeroes on discarded blocks.
*/
bool discard_zeroes_data_unsupported:1;
+
+ /*
+ * Set if the target supports XCOPY.
+ */
+ bool copy_supported:1;
};
/* Each target can link one of these into the table */
Index: linux-4.4-rc4/drivers/md/dm-table.c
===================================================================
--- linux-4.4-rc4.orig/drivers/md/dm-table.c 2015-12-10 17:03:51.000000000 +0100
+++ linux-4.4-rc4/drivers/md/dm-table.c 2015-12-10 17:04:59.000000000 +0100
@@ -286,6 +286,11 @@ static int device_area_is_invalid(struct
limits->logical_block_size >> SECTOR_SHIFT;
char b[BDEVNAME_SIZE];
+ if (ti->copy_supported)
+ limits->max_copy_sectors =
+ min_not_zero(limits->max_copy_sectors,
+ bdev_get_queue(bdev)->limits.max_copy_sectors);
+
/*
* Some devices exist without request functions,
* such as loop devices not yet bound to backing files.
@@ -1256,6 +1261,13 @@ int dm_calculate_queue_limits(struct dm_
ti = dm_table_get_target(table, i++);
+ if (ti->begin)
+ ti_limits.copy_boundary = min(ti_limits.copy_boundary,
+ (unsigned char)__ffs64(ti->begin));
+ if (ti->max_io_len)
+ ti_limits.copy_boundary = min(ti_limits.copy_boundary,
+ (unsigned char)__ffs(ti->max_io_len));
+
if (!ti->type->iterate_devices)
goto combine_limits;
@@ -1289,6 +1301,10 @@ combine_limits:
dm_device_name(table->md),
(unsigned long long) ti->begin,
(unsigned long long) ti->len);
+
+ limits->max_copy_sectors =
+ min_not_zero(limits->max_copy_sectors,
+ ti_limits.max_copy_sectors);
}
return validate_hardware_logical_block_alignment(table, limits);
--
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