From patchwork Wed Mar 23 13:49:40 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiaoguang Wang X-Patchwork-Id: 12789784 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E8BBCC433F5 for ; Wed, 23 Mar 2022 13:49:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244520AbiCWNvS (ORCPT ); Wed, 23 Mar 2022 09:51:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49766 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244514AbiCWNvQ (ORCPT ); Wed, 23 Mar 2022 09:51:16 -0400 Received: from out30-45.freemail.mail.aliyun.com (out30-45.freemail.mail.aliyun.com [115.124.30.45]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3A2C247396; Wed, 23 Mar 2022 06:49:46 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R251e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04400;MF=xiaoguang.wang@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0V80Aqnw_1648043383; Received: from localhost(mailfrom:xiaoguang.wang@linux.alibaba.com fp:SMTPD_---0V80Aqnw_1648043383) by smtp.aliyun-inc.com(127.0.0.1); Wed, 23 Mar 2022 21:49:43 +0800 From: Xiaoguang Wang To: linux-scsi@vger.kernel.org, target-devel@vger.kernel.org Cc: linux-block@vger.kernel.org, bostroesser@gmail.com Subject: [PATCH v2 3/3] scsi: target: tcmu: Use address_space->invalidate_lock Date: Wed, 23 Mar 2022 21:49:40 +0800 Message-Id: <20220323134940.31463-4-xiaoguang.wang@linux.alibaba.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20220323134940.31463-1-xiaoguang.wang@linux.alibaba.com> References: <20220323134940.31463-1-xiaoguang.wang@linux.alibaba.com> Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Currently tcmu_vma_fault() uses udev->cmdr_lock to avoid concurrent find_free_blocks(), which unmaps idle pages and truncates them. This work is really like many filesystem's truncate operations, but they use address_space->invalidate_lock to protect race. This patch replaces cmdr_lock with address_space->invalidate_lock in tcmu fault procedure, which will also make page-fault have concurrency. Signed-off-by: Xiaoguang Wang --- drivers/target/target_core_user.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index 9196188504ec..81bfa553cc67 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -1820,13 +1820,14 @@ static int tcmu_find_mem_index(struct vm_area_struct *vma) static struct page *tcmu_try_get_data_page(struct tcmu_dev *udev, uint32_t dpi) { + struct address_space *mapping = udev->inode->i_mapping; struct page *page; - mutex_lock(&udev->cmdr_lock); + filemap_invalidate_lock_shared(mapping); page = xa_load(&udev->data_pages, dpi); if (likely(page)) { get_page(page); - mutex_unlock(&udev->cmdr_lock); + filemap_invalidate_unlock_shared(mapping); return page; } @@ -1836,7 +1837,7 @@ static struct page *tcmu_try_get_data_page(struct tcmu_dev *udev, uint32_t dpi) */ pr_err("Invalid addr to data page mapping (dpi %u) on device %s\n", dpi, udev->name); - mutex_unlock(&udev->cmdr_lock); + filemap_invalidate_unlock_shared(mapping); return NULL; } @@ -3116,6 +3117,7 @@ static void find_free_blocks(void) loff_t off; u32 pages_freed, total_pages_freed = 0; u32 start, end, block, total_blocks_freed = 0; + struct address_space *mapping; if (atomic_read(&global_page_count) <= tcmu_global_max_pages) return; @@ -3139,6 +3141,8 @@ static void find_free_blocks(void) continue; } + mapping = udev->inode->i_mapping; + filemap_invalidate_lock(mapping); end = udev->dbi_max + 1; block = find_last_bit(udev->data_bitmap, end); if (block == udev->dbi_max) { @@ -3146,6 +3150,7 @@ static void find_free_blocks(void) * The last bit is dbi_max, so it is not possible * reclaim any blocks. */ + filemap_invalidate_unlock(mapping); mutex_unlock(&udev->cmdr_lock); continue; } else if (block == end) { @@ -3159,10 +3164,11 @@ static void find_free_blocks(void) /* Here will truncate the data area from off */ off = udev->data_off + (loff_t)start * udev->data_blk_size; - unmap_mapping_range(udev->inode->i_mapping, off, 0, 1); + unmap_mapping_range(mapping, off, 0, 1); /* Release the block pages */ pages_freed = tcmu_blocks_release(udev, start, end - 1); + filemap_invalidate_unlock(mapping); mutex_unlock(&udev->cmdr_lock); total_pages_freed += pages_freed;