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From: Christoph Hellwig <hch@lst.de>
To: "Dan Williams" <dan.j.williams@intel.com>,
	"Jérôme Glisse" <jglisse@redhat.com>,
	"Jason Gunthorpe" <jgg@mellanox.com>,
	"Ben Skeggs" <bskeggs@redhat.com>
Cc: linux-mm@kvack.org, nouveau@lists.freedesktop.org,
	dri-devel@lists.freedesktop.org, linux-nvdimm@lists.01.org,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 11/25] memremap: lift the devmap_enable manipulation into devm_memremap_pages
Date: Wed, 26 Jun 2019 14:27:10 +0200
Message-ID: <20190626122724.13313-12-hch@lst.de> (raw)
In-Reply-To: <20190626122724.13313-1-hch@lst.de>

Just check if there is a ->page_free operation set and take care of the
static key enable, as well as the put using device managed resources.
Also check that a ->page_free is provided for the pgmaps types that
require it, and check for a valid type as well while we are at it.

Note that this also fixes the fact that hmm never called
dev_pagemap_put_ops and thus would leave the slow path enabled forever,
even after a device driver unload or disable.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/nvdimm/pmem.c | 23 +++--------------
 include/linux/mm.h    | 10 --------
 kernel/memremap.c     | 59 +++++++++++++++++++++++++++----------------
 mm/hmm.c              |  2 --
 4 files changed, 41 insertions(+), 53 deletions(-)

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 9dac48359353..48767171a4df 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -334,11 +334,6 @@ static void pmem_release_disk(void *__pmem)
 	put_disk(pmem->disk);
 }
 
-static void pmem_release_pgmap_ops(void *__pgmap)
-{
-	dev_pagemap_put_ops();
-}
-
 static void pmem_pagemap_page_free(struct page *page, void *data)
 {
 	wake_up_var(&page->_refcount);
@@ -350,16 +345,6 @@ static const struct dev_pagemap_ops fsdax_pagemap_ops = {
 	.cleanup		= pmem_pagemap_cleanup,
 };
 
-static int setup_pagemap_fsdax(struct device *dev, struct dev_pagemap *pgmap)
-{
-	dev_pagemap_get_ops();
-	if (devm_add_action_or_reset(dev, pmem_release_pgmap_ops, pgmap))
-		return -ENOMEM;
-	pgmap->type = MEMORY_DEVICE_FS_DAX;
-	pgmap->ops = &fsdax_pagemap_ops;
-	return 0;
-}
-
 static int pmem_attach_disk(struct device *dev,
 		struct nd_namespace_common *ndns)
 {
@@ -415,8 +400,8 @@ static int pmem_attach_disk(struct device *dev,
 	pmem->pfn_flags = PFN_DEV;
 	pmem->pgmap.ref = &q->q_usage_counter;
 	if (is_nd_pfn(dev)) {
-		if (setup_pagemap_fsdax(dev, &pmem->pgmap))
-			return -ENOMEM;
+		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);
@@ -428,8 +413,8 @@ static int pmem_attach_disk(struct device *dev,
 	} else if (pmem_should_map_pages(dev)) {
 		memcpy(&pmem->pgmap.res, &nsio->res, sizeof(pmem->pgmap.res));
 		pmem->pgmap.altmap_valid = false;
-		if (setup_pagemap_fsdax(dev, &pmem->pgmap))
-			return -ENOMEM;
+		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;
 		memcpy(&bb_res, &pmem->pgmap.res, sizeof(bb_res));
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 6e4b9be08b13..aa3970291cdf 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -932,8 +932,6 @@ static inline bool is_zone_device_page(const struct page *page)
 #endif
 
 #ifdef CONFIG_DEV_PAGEMAP_OPS
-void dev_pagemap_get_ops(void);
-void dev_pagemap_put_ops(void);
 void __put_devmap_managed_page(struct page *page);
 DECLARE_STATIC_KEY_FALSE(devmap_managed_key);
 static inline bool put_devmap_managed_page(struct page *page)
@@ -973,14 +971,6 @@ static inline bool is_pci_p2pdma_page(const struct page *page)
 #endif /* CONFIG_PCI_P2PDMA */
 
 #else /* CONFIG_DEV_PAGEMAP_OPS */
-static inline void dev_pagemap_get_ops(void)
-{
-}
-
-static inline void dev_pagemap_put_ops(void)
-{
-}
-
 static inline bool put_devmap_managed_page(struct page *page)
 {
 	return false;
diff --git a/kernel/memremap.c b/kernel/memremap.c
index 00c1ceb60c19..3219a4c91d07 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -17,6 +17,35 @@ static DEFINE_XARRAY(pgmap_array);
 #define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
 #define SECTION_SIZE (1UL << PA_SECTION_SHIFT)
 
+#ifdef CONFIG_DEV_PAGEMAP_OPS
+DEFINE_STATIC_KEY_FALSE(devmap_managed_key);
+EXPORT_SYMBOL(devmap_managed_key);
+static atomic_t devmap_managed_enable;
+
+static void devmap_managed_enable_put(void *data)
+{
+	if (atomic_dec_and_test(&devmap_managed_enable))
+		static_branch_disable(&devmap_managed_key);
+}
+
+static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap)
+{
+	if (!pgmap->ops->page_free) {
+		WARN(1, "Missing page_free method\n");
+		return -EINVAL;
+	}
+
+	if (atomic_inc_return(&devmap_managed_enable) == 1)
+		static_branch_enable(&devmap_managed_key);
+	return devm_add_action_or_reset(dev, devmap_managed_enable_put, NULL);
+}
+#else
+static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap)
+{
+	return -EINVAL;
+}
+#endif /* CONFIG_DEV_PAGEMAP_OPS */
+
 #if IS_ENABLED(CONFIG_DEVICE_PRIVATE)
 vm_fault_t device_private_entry_fault(struct vm_area_struct *vma,
 		       unsigned long addr,
@@ -156,6 +185,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
 	};
 	pgprot_t pgprot = PAGE_KERNEL;
 	int error, nid, is_ram;
+	bool need_devmap_managed = true;
 
 	switch (pgmap->type) {
 	case MEMORY_DEVICE_PRIVATE:
@@ -173,6 +203,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
 		break;
 	case MEMORY_DEVICE_DEVDAX:
 	case MEMORY_DEVICE_PCI_P2PDMA:
+		need_devmap_managed = false;
 		break;
 	default:
 		WARN(1, "Invalid pgmap type %d\n", pgmap->type);
@@ -185,6 +216,12 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
 		return ERR_PTR(-EINVAL);
 	}
 
+	if (need_devmap_managed) {
+		error = devmap_managed_enable_get(dev, pgmap);
+		if (error)
+			return ERR_PTR(error);
+	}
+
 	align_start = res->start & ~(SECTION_SIZE - 1);
 	align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
 		- align_start;
@@ -351,28 +388,6 @@ struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
 EXPORT_SYMBOL_GPL(get_dev_pagemap);
 
 #ifdef CONFIG_DEV_PAGEMAP_OPS
-DEFINE_STATIC_KEY_FALSE(devmap_managed_key);
-EXPORT_SYMBOL(devmap_managed_key);
-static atomic_t devmap_enable;
-
-/*
- * Toggle the static key for ->page_free() callbacks when dev_pagemap
- * pages go idle.
- */
-void dev_pagemap_get_ops(void)
-{
-	if (atomic_inc_return(&devmap_enable) == 1)
-		static_branch_enable(&devmap_managed_key);
-}
-EXPORT_SYMBOL_GPL(dev_pagemap_get_ops);
-
-void dev_pagemap_put_ops(void)
-{
-	if (atomic_dec_and_test(&devmap_enable))
-		static_branch_disable(&devmap_managed_key);
-}
-EXPORT_SYMBOL_GPL(dev_pagemap_put_ops);
-
 void __put_devmap_managed_page(struct page *page)
 {
 	int count = page_ref_dec_return(page);
diff --git a/mm/hmm.c b/mm/hmm.c
index 987793fba923..5b0bd5f6a74f 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -1415,8 +1415,6 @@ struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
 	void *result;
 	int ret;
 
-	dev_pagemap_get_ops();
-
 	devmem = devm_kzalloc(device, sizeof(*devmem), GFP_KERNEL);
 	if (!devmem)
 		return ERR_PTR(-ENOMEM);
-- 
2.20.1


  parent reply index

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-26 12:26 dev_pagemap related cleanups v3 Christoph Hellwig
2019-06-26 12:27 ` [PATCH 01/25] mm: remove the unused ARCH_HAS_HMM_DEVICE Kconfig option Christoph Hellwig
2019-06-26 12:27 ` [PATCH 02/25] mm: remove the struct hmm_device infrastructure Christoph Hellwig
2019-06-26 12:27 ` [PATCH 03/25] mm: remove hmm_devmem_add_resource Christoph Hellwig
2019-06-27 16:18   ` Jason Gunthorpe
2019-06-27 16:54     ` Christoph Hellwig
2019-06-26 12:27 ` [PATCH 04/25] mm: remove MEMORY_DEVICE_PUBLIC support Christoph Hellwig
2019-06-26 16:00   ` Dan Williams
2019-06-26 17:14     ` Ira Weiny
2019-06-26 18:49       ` Ira Weiny
2019-06-26 12:27 ` [PATCH 05/25] mm: don't clear ->mapping in hmm_devmem_free Christoph Hellwig
2019-06-26 12:27 ` [PATCH 06/25] mm: export alloc_pages_vma Christoph Hellwig
2019-06-26 12:36   ` Michal Hocko
2019-06-26 12:27 ` [PATCH 07/25] mm: factor out a devm_request_free_mem_region helper Christoph Hellwig
2019-06-26 12:27 ` [PATCH 08/25] memremap: validate the pagemap type passed to devm_memremap_pages Christoph Hellwig
2019-06-26 18:01   ` Ira Weiny
2019-06-26 12:27 ` [PATCH 09/25] memremap: move dev_pagemap callbacks into a separate structure Christoph Hellwig
2019-06-26 12:27 ` [PATCH 10/25] memremap: pass a struct dev_pagemap to ->kill and ->cleanup Christoph Hellwig
2019-06-26 12:27 ` Christoph Hellwig [this message]
2019-06-26 19:04   ` [PATCH 11/25] memremap: lift the devmap_enable manipulation into devm_memremap_pages Ira Weiny
2019-06-27  8:50     ` Christoph Hellwig
2019-06-26 12:27 ` [PATCH 12/25] memremap: add a migrate_to_ram method to struct dev_pagemap_ops Christoph Hellwig
2019-06-27 16:29   ` Jason Gunthorpe
2019-06-27 16:53     ` Christoph Hellwig
2019-06-26 12:27 ` [PATCH 13/25] memremap: remove the data field in struct dev_pagemap Christoph Hellwig
2019-06-26 12:27 ` [PATCH 14/25] memremap: replace the altmap_valid field with a PGMAP_ALTMAP_VALID flag Christoph Hellwig
2019-06-26 21:13   ` Ira Weiny
2019-06-26 12:27 ` [PATCH 15/25] memremap: provide an optional internal refcount in struct dev_pagemap Christoph Hellwig
2019-06-26 21:47   ` Ira Weiny
2019-06-27  8:51     ` Christoph Hellwig
2019-06-26 12:27 ` [PATCH 16/25] device-dax: use the dev_pagemap internal refcount Christoph Hellwig
2019-06-26 21:48   ` Ira Weiny
2019-06-28 15:38   ` Jason Gunthorpe
2019-06-28 16:27     ` Dan Williams
2019-06-28 17:02       ` Jason Gunthorpe
2019-06-28 17:08         ` Dan Williams
2019-06-28 17:10           ` Dan Williams
2019-06-28 18:29             ` Jason Gunthorpe
2019-06-28 18:44               ` Dan Williams
2019-06-28 18:51                 ` Christoph Hellwig
2019-06-28 18:59                   ` Dan Williams
2019-06-28 19:02                     ` Christoph Hellwig
2019-06-28 19:14                       ` Dan Williams
2019-07-02 22:35                         ` Andrew Morton
2019-06-26 12:27 ` [PATCH 17/25] PCI/P2PDMA: " Christoph Hellwig
2019-06-26 21:49   ` Ira Weiny
2019-06-27 18:49   ` Logan Gunthorpe
2019-06-26 12:27 ` [PATCH 18/25] nouveau: use alloc_page_vma directly Christoph Hellwig
2019-06-26 12:27 ` [PATCH 19/25] nouveau: use devm_memremap_pages directly Christoph Hellwig
2019-06-26 12:27 ` [PATCH 20/25] mm: remove hmm_vma_alloc_locked_page Christoph Hellwig
2019-06-27 16:26   ` Jason Gunthorpe
2019-06-26 12:27 ` [PATCH 21/25] mm: remove hmm_devmem_add Christoph Hellwig
2019-06-26 12:27 ` [PATCH 22/25] mm: simplify ZONE_DEVICE page private data Christoph Hellwig
2019-06-26 12:27 ` [PATCH 23/25] mm: sort out the DEVICE_PRIVATE Kconfig mess Christoph Hellwig
2019-06-26 21:36   ` Ira Weiny
2019-06-26 12:27 ` [PATCH 24/25] mm: remove the HMM config option Christoph Hellwig
2019-06-26 21:38   ` Ira Weiny
2019-06-27 16:29   ` Jason Gunthorpe
2019-06-26 12:27 ` [PATCH 25/25] mm: don't select MIGRATE_VMA_HELPER from HMM_MIRROR Christoph Hellwig

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