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 <mpato...@redhat.com>
---
drivers/md/dm-table.c | 9 +++++++++
drivers/md/dm.c | 42 +++++++++++++++++++++++++++++++++++++++---
include/linux/device-mapper.h | 5 +++++
3 files changed, 53 insertions(+), 3 deletions(-)
Index: linux-3.18-rc1/drivers/md/dm.c
===================================================================
--- linux-3.18-rc1.orig/drivers/md/dm.c 2014-10-21 00:46:30.000000000 +0200
+++ linux-3.18-rc1/drivers/md/dm.c 2014-10-21 00:49:09.000000000 +0200
@@ -1559,6 +1559,31 @@ 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, NULL);
+
+ ci->sector += ci->sector_count;
+ ci->sector_count = 0;
+
+ return 0;
+}
+
/*
* Select the correct strategy for processing a non-flush bio.
*/
@@ -1572,6 +1597,8 @@ 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))
@@ -1656,6 +1683,11 @@ static int dm_merge_bvec(struct request_
if (!dm_target_is_valid(ti))
goto out;
+ if (unlikely((bvm->bi_rw & REQ_COPY) != 0)) {
+ if (!ti->copy_supported)
+ goto out_ret_max_size;
+ }
+
/*
* Find maximum amount of I/O that won't need splitting
*/
@@ -1679,17 +1711,21 @@ static int dm_merge_bvec(struct request_
* entries. So always set max_size to 0, and the code below allows
* just one page.
*/
- else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9)
+ else if (likely(!(bvm->bi_rw & REQ_COPY)) &&
+ queue_max_hw_sectors(q) <= PAGE_SIZE >> 9)
max_size = 0;
out:
- dm_put_live_table_fast(md);
/*
* Always allow an entire first page
*/
- if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
+ if (likely(!(bvm->bi_rw & REQ_COPY)) &&
+ max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
max_size = biovec->bv_len;
+out_ret_max_size:
+ dm_put_live_table_fast(md);
+
return max_size;
}
Index: linux-3.18-rc1/include/linux/device-mapper.h
===================================================================
--- linux-3.18-rc1.orig/include/linux/device-mapper.h 2014-10-21
00:42:40.000000000 +0200
+++ linux-3.18-rc1/include/linux/device-mapper.h 2014-10-21
00:49:09.000000000 +0200
@@ -251,6 +251,11 @@ 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-3.18-rc1/drivers/md/dm-table.c
===================================================================
--- linux-3.18-rc1.orig/drivers/md/dm-table.c 2014-10-21 00:34:45.000000000
+0200
+++ linux-3.18-rc1/drivers/md/dm-table.c 2014-10-21 00:49:09.000000000
+0200
@@ -443,6 +443,11 @@ static int dm_set_device_limits(struct d
q->limits.alignment_offset,
(unsigned long long) start << SECTOR_SHIFT);
+ if (ti->copy_supported)
+ limits->max_copy_sectors =
+ min_not_zero(limits->max_copy_sectors,
+ bdev_get_queue(bdev)->limits.max_copy_sectors);
+
/*
* Check if merge fn is supported.
* If not we'll force DM to use PAGE_SIZE or
@@ -1264,6 +1269,10 @@ 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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