From patchwork Tue Oct 19 07:36:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 12568837 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A0AA82C80 for ; Tue, 19 Oct 2021 07:36:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=xEmF1XJ1P1x7JazxiSTgX0H5G/Dg0T1jC0FmUdRQvXs=; b=hK9AK8I7swt7mIxSGHoIUJieft 8tXSQHr2GJU3cvML4qqKjubt5uucpLlUyDnpUnphU+fiObFYEEwAyVWXCLk09drNHXFghDU8gdcAF K9kqXW/AzjGClCGaKw53dLZ4+HXwDZx6jiymyHFPEUittOUN4VSczxmqLPSu39xgcOh2HLcjGSMzx +UCRcAnRL0m4KKy3wmpi1XEOBlAyLy9JxPVDCxnotSlArbKMpeGh8OPCW1Ea7jZiEp+N4fmS7kKbe PvATbw2K7qYhohf3APjpo60CFwHu/NhNi457kCgKVMAVJWAp1bUEkOA36etFZbC7lw/Tk9VyGD77V lG+54jyA==; Received: from 089144192247.atnat0001.highway.a1.net ([89.144.192.247] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mcjg1-000QWO-Mq; Tue, 19 Oct 2021 07:36:50 +0000 From: Christoph Hellwig To: Dan Williams Cc: Vishal Verma , Dave Jiang , Ira Weiny , Jens Axboe , Yi Zhang , linux-block@vger.kernel.org, nvdimm@lists.linux.dev, linux-mm@kvack.org Subject: [PATCH 1/2] nvdimm/pmem: stop using q_usage_count as external pgmap refcount Date: Tue, 19 Oct 2021 09:36:40 +0200 Message-Id: <20211019073641.2323410-2-hch@lst.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211019073641.2323410-1-hch@lst.de> References: <20211019073641.2323410-1-hch@lst.de> Precedence: bulk X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Originally all DAX access when through block_device operations and thus needed a queue reference. But since commit cccbce671582 ("filesystem-dax: convert to dax_direct_access()") all this happens at the DAX device level which uses its own refcounting. Having the external refcount thus wasn't needed but has otherwise been harmless for long time. But now that "block: drain file system I/O on del_gendisk" waits for q_usage_count to reach 0 in del_gendisk this whole scheme can't work anymore (and pmem is the only driver abusing q_usage_count like that). So switch to the internal reference and remove the unbalanced blk_freeze_queue_start that is taken care of by del_gendisk. Fixes: 8e141f9eb803 ("block: drain file system I/O on del_gendisk") Reported-by: Yi Zhang Signed-off-by: Christoph Hellwig --- drivers/nvdimm/pmem.c | 33 ++------------------------------- 1 file changed, 2 insertions(+), 31 deletions(-) diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c index 72de88ff0d30d..f576ee0ce7968 100644 --- a/drivers/nvdimm/pmem.c +++ b/drivers/nvdimm/pmem.c @@ -333,26 +333,6 @@ static const struct attribute_group *pmem_attribute_groups[] = { NULL, }; -static void pmem_pagemap_cleanup(struct dev_pagemap *pgmap) -{ - struct pmem_device *pmem = pgmap->owner; - - blk_cleanup_disk(pmem->disk); -} - -static void pmem_release_queue(void *pgmap) -{ - pmem_pagemap_cleanup(pgmap); -} - -static void pmem_pagemap_kill(struct dev_pagemap *pgmap) -{ - struct request_queue *q = - container_of(pgmap->ref, struct request_queue, q_usage_counter); - - blk_freeze_queue_start(q); -} - static void pmem_release_disk(void *__pmem) { struct pmem_device *pmem = __pmem; @@ -360,12 +340,9 @@ static void pmem_release_disk(void *__pmem) kill_dax(pmem->dax_dev); put_dax(pmem->dax_dev); del_gendisk(pmem->disk); -} -static const struct dev_pagemap_ops fsdax_pagemap_ops = { - .kill = pmem_pagemap_kill, - .cleanup = pmem_pagemap_cleanup, -}; + blk_cleanup_disk(pmem->disk); +} static int pmem_attach_disk(struct device *dev, struct nd_namespace_common *ndns) @@ -428,10 +405,8 @@ static int pmem_attach_disk(struct device *dev, pmem->disk = disk; pmem->pgmap.owner = pmem; pmem->pfn_flags = PFN_DEV; - pmem->pgmap.ref = &q->q_usage_counter; if (is_nd_pfn(dev)) { pmem->pgmap.type = MEMORY_DEVICE_FS_DAX; - pmem->pgmap.ops = &fsdax_pagemap_ops; addr = devm_memremap_pages(dev, &pmem->pgmap); pfn_sb = nd_pfn->pfn_sb; pmem->data_offset = le64_to_cpu(pfn_sb->dataoff); @@ -445,16 +420,12 @@ static int pmem_attach_disk(struct device *dev, pmem->pgmap.range.end = res->end; pmem->pgmap.nr_range = 1; pmem->pgmap.type = MEMORY_DEVICE_FS_DAX; - pmem->pgmap.ops = &fsdax_pagemap_ops; addr = devm_memremap_pages(dev, &pmem->pgmap); pmem->pfn_flags |= PFN_MAP; bb_range = pmem->pgmap.range; } else { addr = devm_memremap(dev, pmem->phys_addr, pmem->size, ARCH_MEMREMAP_PMEM); - if (devm_add_action_or_reset(dev, pmem_release_queue, - &pmem->pgmap)) - return -ENOMEM; bb_range.start = res->start; bb_range.end = res->end; }