Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751391AbdFAHCL (ORCPT ); Thu, 1 Jun 2017 03:02:11 -0400 Received: from mail.linux-iscsi.org ([67.23.28.174]:41485 "EHLO linux-iscsi.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750926AbdFAHCK (ORCPT ); Thu, 1 Jun 2017 03:02:10 -0400 From: "Nicholas A. Bellinger" To: target-devel Cc: linux-scsi , lkml , Nicholas Bellinger , Christoph Hellwig , Mike Christie , Hannes Reinecke , "Martin K. Petersen" , Jens Axboe Subject: [PATCH-v2] target/iblock: Convert WRITE_SAME to blkdev_issue_zeroout Date: Thu, 1 Jun 2017 07:05:02 +0000 Message-Id: <1496300702-21835-1-git-send-email-nab@linux-iscsi.org> X-Mailer: git-send-email 1.7.2.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4473 Lines: 125 From: Nicholas Bellinger The people who are actively using iblock_execute_write_same_direct() are doing so in the context of ESX VAAI BlockZero, together with EXTENDED_COPY and COMPARE_AND_WRITE primitives. In practice though I've not seen any users of IBLOCK WRITE_SAME for anything other than VAAI BlockZero, so just using blkdev_issue_zeroout() when available, and falling back to iblock_execute_write_same() if the WRITE_SAME buffer contains anything other than zeros should be OK. (Hook up max_write_zeroes_sectors to signal LBPRZ feature bit in target_configure_unmap_from_queue - nab) Signed-off-by: Christoph Hellwig Cc: Christoph Hellwig Cc: Mike Christie Cc: Hannes Reinecke Cc: Martin K. Petersen Cc: Jens Axboe Signed-off-by: Nicholas Bellinger --- drivers/target/target_core_device.c | 2 +- drivers/target/target_core_iblock.c | 44 +++++++++++++++++++++++-------------- 2 files changed, 28 insertions(+), 18 deletions(-) diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c index 8add07f38..a5762e6 100644 --- a/drivers/target/target_core_device.c +++ b/drivers/target/target_core_device.c @@ -851,7 +851,7 @@ bool target_configure_unmap_from_queue(struct se_dev_attrib *attrib, attrib->unmap_granularity = q->limits.discard_granularity / block_size; attrib->unmap_granularity_alignment = q->limits.discard_alignment / block_size; - attrib->unmap_zeroes_data = 0; + attrib->unmap_zeroes_data = (q->limits.max_write_zeroes_sectors); return true; } EXPORT_SYMBOL(target_configure_unmap_from_queue); diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c index bb069eb..b204413 100644 --- a/drivers/target/target_core_iblock.c +++ b/drivers/target/target_core_iblock.c @@ -86,6 +86,7 @@ static int iblock_configure_device(struct se_device *dev) struct block_device *bd = NULL; struct blk_integrity *bi; fmode_t mode; + unsigned int max_write_zeroes_sectors; int ret = -ENOMEM; if (!(ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)) { @@ -129,7 +130,11 @@ static int iblock_configure_device(struct se_device *dev) * Enable write same emulation for IBLOCK and use 0xFFFF as * the smaller WRITE_SAME(10) only has a two-byte block count. */ - dev->dev_attrib.max_write_same_len = 0xFFFF; + max_write_zeroes_sectors = bdev_write_zeroes_sectors(bd); + if (max_write_zeroes_sectors) + dev->dev_attrib.max_write_same_len = max_write_zeroes_sectors; + else + dev->dev_attrib.max_write_same_len = 0xFFFF; if (blk_queue_nonrot(q)) dev->dev_attrib.is_nonrot = 1; @@ -415,28 +420,31 @@ static void iblock_end_io_flush(struct bio *bio) } static sense_reason_t -iblock_execute_write_same_direct(struct block_device *bdev, struct se_cmd *cmd) +iblock_execute_zero_out(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; + unsigned char *buf, zero = 0x00, *p = &zero; + int rc, 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); - } + buf = kmap(sg_page(sg)) + sg->offset; + if (!buf) + return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; + /* + * Fall back to block_execute_write_same() slow-path if + * incoming WRITE_SAME payload does not contain zeros. + */ + rc = memcmp(buf, p, cmd->data_length); + kunmap(sg_page(sg)); + + if (rc) + return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; - ret = blkdev_issue_write_same(bdev, + ret = blkdev_issue_zeroout(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); + GFP_KERNEL, false); if (ret) return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; @@ -472,8 +480,10 @@ static void iblock_end_io_flush(struct bio *bio) return TCM_INVALID_CDB_FIELD; } - if (bdev_write_same(bdev)) - return iblock_execute_write_same_direct(bdev, cmd); + if (bdev_write_zeroes_sectors(bdev)) { + if (!iblock_execute_zero_out(bdev, cmd)) + return 0; + } ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL); if (!ibr) -- 1.9.1