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 | 9 +++++++++ drivers/md/dm.c | 42 +++++++++++++++++++++++++++++++++++++++--- include/linux/device-mapper.h | 5 +++++ 3 files changed, 53 insertions(+), 3 deletions(-) Index: linux-3.16-rc5/drivers/md/dm.c =================================================================== --- linux-3.16-rc5.orig/drivers/md/dm.c 2014-07-14 16:26:24.000000000 +0200 +++ linux-3.16-rc5/drivers/md/dm.c 2014-07-14 16:41:15.000000000 +0200 @@ -1403,6 +1403,31 @@ 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. */ @@ -1416,6 +1441,8 @@ 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)) @@ -1500,6 +1527,11 @@ 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 */ @@ -1523,17 +1555,21 @@ 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-3.16-rc5/include/linux/device-mapper.h =================================================================== --- linux-3.16-rc5.orig/include/linux/device-mapper.h 2014-07-14 16:26:24.000000000 +0200 +++ linux-3.16-rc5/include/linux/device-mapper.h 2014-07-14 16:41:15.000000000 +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-3.16-rc5/drivers/md/dm-table.c =================================================================== --- linux-3.16-rc5.orig/drivers/md/dm-table.c 2014-07-14 16:26:25.000000000 +0200 +++ linux-3.16-rc5/drivers/md/dm-table.c 2014-07-14 16:41:15.000000000 +0200 @@ -489,6 +489,11 @@ 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 @@ -1298,6 +1303,10 @@ 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); -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel