From 07b6319687026bdac90a0bb9eeb0509f1ff27179 Mon Sep 17 00:00:00 2001 From: Mike Christie Date: Wed, 24 Feb 2016 13:56:33 -0600 Subject: target/iblock: pass WRITE_SAME to device if possible This patch has iblock pass the WRITE_SAME command to the device for offloading if possible. It is similar to what is done for UNMAP/discards, except that we export a large max write same value to the initiator, and then rely on the block layer to break it up into multiple requests if it cannot fit into one. v2. - Drop file backend changes and move helper function to iblock backend. Signed-off-by: Mike Christie Signed-off-by: Nicholas Bellinger --- drivers/target/target_core_iblock.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) (limited to 'drivers/target') diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c index abe4eb997a84..026a758e5778 100644 --- a/drivers/target/target_core_iblock.c +++ b/drivers/target/target_core_iblock.c @@ -412,9 +412,40 @@ iblock_execute_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb) return 0; } +static sense_reason_t +iblock_execute_write_same_direct(struct block_device *bdev, struct se_cmd *cmd) +{ + struct se_device *dev = cmd->se_dev; + struct scatterlist *sg = &cmd->t_data_sg[0]; + struct page *page = NULL; + int ret; + + if (sg->offset) { + page = alloc_page(GFP_KERNEL); + if (!page) + return TCM_OUT_OF_RESOURCES; + sg_copy_to_buffer(sg, cmd->t_data_nents, page_address(page), + dev->dev_attrib.block_size); + } + + ret = blkdev_issue_write_same(bdev, + target_to_linux_sector(dev, cmd->t_task_lba), + target_to_linux_sector(dev, + sbc_get_write_same_sectors(cmd)), + GFP_KERNEL, page ? page : sg_page(sg)); + if (page) + __free_page(page); + if (ret) + return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; + + target_complete_cmd(cmd, GOOD); + return 0; +} + static sense_reason_t iblock_execute_write_same(struct se_cmd *cmd) { + struct block_device *bdev = IBLOCK_DEV(cmd->se_dev)->ibd_bd; struct iblock_req *ibr; struct scatterlist *sg; struct bio *bio; @@ -439,6 +470,9 @@ iblock_execute_write_same(struct se_cmd *cmd) return TCM_INVALID_CDB_FIELD; } + if (bdev_write_same(bdev)) + return iblock_execute_write_same_direct(bdev, cmd); + ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL); if (!ibr) goto fail; -- cgit v1.2.3