From patchwork Thu Jun 1 06:27:01 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Nicholas A. Bellinger" X-Patchwork-Id: 9758735 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 8C60160390 for ; Thu, 1 Jun 2017 06:28:10 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7CF41284DC for ; Thu, 1 Jun 2017 06:28:10 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 718B2284F5; Thu, 1 Jun 2017 06:28:10 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CA6A6284E4 for ; Thu, 1 Jun 2017 06:28:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750848AbdFAG2F (ORCPT ); Thu, 1 Jun 2017 02:28:05 -0400 Received: from mail.linux-iscsi.org ([67.23.28.174]:46793 "EHLO linux-iscsi.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751054AbdFAG1F (ORCPT ); Thu, 1 Jun 2017 02:27:05 -0400 Received: from [192.168.1.66] (75-37-194-224.lightspeed.lsatca.sbcglobal.net [75.37.194.224]) (using SSLv3 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: nab) by linux-iscsi.org (Postfix) with ESMTPSA id 613FC1740F7; Thu, 1 Jun 2017 06:29:58 +0000 (UTC) Message-ID: <1496298421.27407.206.camel@haakon3.risingtidesystems.com> Subject: Re: [PATCH 2/8] target: remove iblock WRITE_SAME passthrough support From: "Nicholas A. Bellinger" To: Christoph Hellwig Cc: axboe@kernel.dk, martin.petersen@oracle.com, philipp.reisner@linbit.com, lars.ellenberg@linbit.com, target-devel@vger.kernel.org, linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, drbd-dev@lists.linbit.com, dm-devel@redhat.com Date: Wed, 31 May 2017 23:27:01 -0700 In-Reply-To: <1491975041.8231.131.camel@haakon3.risingtidesystems.com> References: <20170410160807.23674-1-hch@lst.de> <20170410160807.23674-3-hch@lst.de> <1491975041.8231.131.camel@haakon3.risingtidesystems.com> X-Mailer: Evolution 3.4.4-1 Mime-Version: 1.0 Sender: target-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: target-devel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Hey HCH & Jens, Is this already queued up for v4.13 to address the missing LBPRZ feature bit..? If not, I'll happy to take it via target-pending along with the following to re-enable it via max_write_zeroes_sectors. Any objections..? On Tue, 2017-04-11 at 22:30 -0700, Nicholas A. Bellinger wrote: > On Mon, 2017-04-10 at 18:08 +0200, Christoph Hellwig wrote: > > Use the pscsi driver to support arbitrary command passthrough > > instead. > > > > 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. Just using PSCSI is not > an option for them. > > 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. > > How about something like the following below..? > > This would bring parity to how blkdev_issue_write_same() works atm wrt > to synchronous bio completions. However, most folks with a raw > make_request or blk-mq backend driver that supports multiple GB/sec of > zero bandwidth end up changing IBLOCK to support asynchronous > REQ_WRITE_SAME completions anyways. > > I'd be happy to add support for that using __blkdev_issue_zeroout() once > the basic conversion is in place. > > From ff74012eaff38f9fa0d74aca60507b9964f484ce Mon Sep 17 00:00:00 2001 > From: Nicholas Bellinger > Date: Tue, 11 Apr 2017 22:21:47 -0700 > Subject: [PATCH] target/iblock: Convert WRITE_SAME to blkdev_issue_zeroout > > Signed-off-by: Nicholas Bellinger > --- > 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 d316ed5..5bfde20 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) --- To unsubscribe from this list: send the line "unsubscribe target-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c index d2f089c..e7caf78 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);