From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Christoph Hellwig To: axboe@kernel.dk, martin.petersen@oracle.com, philipp.reisner@linbit.com, lars.ellenberg@linbit.com, target-devel@vger.kernel.org Cc: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, drbd-dev@lists.linbit.com, dm-devel@redhat.com, Nicholas Bellinger Subject: [PATCH 2/8] target/iblock: convert WRITE_SAME to blkdev_issue_zeroout Date: Wed, 12 Apr 2017 10:48:03 +0200 Message-Id: <20170412084809.8245-3-hch@lst.de> In-Reply-To: <20170412084809.8245-1-hch@lst.de> References: <20170412084809.8245-1-hch@lst.de> List-ID: 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. Signed-off-by: Christoph Hellwig --- drivers/target/target_core_iblock.c | 44 +++++++++++++++++++++++-------------- 1 file changed, 27 insertions(+), 17 deletions(-) diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c index d316ed537d59..5bfde20481d7 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 @@ iblock_execute_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb) } 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 @@ 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); + 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) -- 2.11.0 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: [PATCH 2/8] target/iblock: convert WRITE_SAME to blkdev_issue_zeroout Date: Wed, 12 Apr 2017 10:48:03 +0200 Message-ID: <20170412084809.8245-3-hch@lst.de> References: <20170412084809.8245-1-hch@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170412084809.8245-1-hch@lst.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: axboe@kernel.dk, martin.petersen@oracle.com, philipp.reisner@linbit.com, lars.ellenberg@linbit.com, target-devel@vger.kernel.org Cc: linux-block@vger.kernel.org, dm-devel@redhat.com, Nicholas Bellinger , linux-scsi@vger.kernel.org, drbd-dev@lists.linbit.com List-Id: linux-scsi@vger.kernel.org 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. Signed-off-by: Christoph Hellwig --- drivers/target/target_core_iblock.c | 44 +++++++++++++++++++++++-------------- 1 file changed, 27 insertions(+), 17 deletions(-) diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c index d316ed537d59..5bfde20481d7 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 @@ iblock_execute_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb) } 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 @@ 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); + 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) -- 2.11.0