From 3dd60fb9d95db9c78fec86ba4df20852a7b974ba Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 19 Oct 2021 09:36:40 +0200 Subject: [PATCH] nvdimm/pmem: stop using q_usage_count as external pgmap refcount 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 Link: https://lore.kernel.org/r/20211019073641.2323410-2-hch@lst.de Signed-off-by: Dan Williams --- 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 ef4950f80832..054154c22899 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) @@ -427,10 +404,8 @@ 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); @@ -444,16 +419,12 @@ 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; }