Hi Jens, Several embedded storage controllers need support for DMA segments that are smaller than the size of one virtual memory page. Hence this patch series. Please consider this patch series for the next merge window. Thanks, Bart. Changes compared to v1: - Added a CONFIG variable that controls whether or not small segment support is enabled. - Improved patch descriptions. Bart Van Assche (8): block: Introduce CONFIG_BLK_SUB_PAGE_SEGMENTS and QUEUE_FLAG_SUB_PAGE_SEGMENTS block: Support configuring limits below the page size block: Support submitting passthrough requests with small segments block: Add support for filesystem requests and small segments block: Add support for small segments in blk_rq_map_user_iov() scsi: core: Set the SUB_PAGE_SEGMENTS request queue flag scsi_debug: Support configuring the maximum segment size null_blk: Support configuring the maximum segment size block/Kconfig | 9 +++++++ block/blk-map.c | 43 ++++++++++++++++++++++++++----- block/blk-merge.c | 6 +++-- block/blk-mq.c | 2 ++ block/blk-settings.c | 20 ++++++++------ block/blk.h | 14 +++++++++- drivers/block/null_blk/main.c | 20 +++++++++++--- drivers/block/null_blk/null_blk.h | 1 + drivers/scsi/scsi_debug.c | 3 +++ drivers/scsi/scsi_lib.c | 2 ++ include/linux/blkdev.h | 7 +++++ 11 files changed, 107 insertions(+), 20 deletions(-)