memremap: remove support for external pgmap refcounts

No driver is left using the external pgmap refcount, so remove the
code to support it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20211028151017.50234-1-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 8d47cb7..454d5f6 100644 (file)
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -219,7 +219,7 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size,
        error = gen_pool_add_owner(p2pdma->pool, (unsigned long)addr,
                        pci_bus_address(pdev, bar) + offset,
                        range_len(&pgmap->range), dev_to_node(&pdev->dev),
-                       pgmap->ref);
+                       &pgmap->ref);
        if (error)
                goto pages_free;
 

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index c0e9d35..a8bc588 100644 (file)
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -73,16 +73,6 @@ struct dev_pagemap_ops {
        void (*page_free)(struct page *page);
 
        /*
-        * Transition the refcount in struct dev_pagemap to the dead state.
-        */
-       void (*kill)(struct dev_pagemap *pgmap);
-
-       /*
-        * Wait for refcount in struct dev_pagemap to be idle and reap it.
-        */
-       void (*cleanup)(struct dev_pagemap *pgmap);
-
-       /*
         * Used for private (un-addressable) device memory only.  Must migrate
         * the page back to a CPU accessible page.
         */
@@ -95,8 +85,7 @@ struct dev_pagemap_ops {
  * struct dev_pagemap - metadata for ZONE_DEVICE mappings
  * @altmap: pre-allocated/reserved memory for vmemmap allocations
  * @ref: reference count that pins the devm_memremap_pages() mapping
- * @internal_ref: internal reference if @ref is not provided by the caller
- * @done: completion for @internal_ref
+ * @done: completion for @ref
  * @type: memory type: see MEMORY_* in memory_hotplug.h
  * @flags: PGMAP_* flags to specify defailed behavior
  * @ops: method table
@@ -109,8 +98,7 @@ struct dev_pagemap_ops {
  */
 struct dev_pagemap {
        struct vmem_altmap altmap;
-       struct percpu_ref *ref;
-       struct percpu_ref internal_ref;
+       struct percpu_ref ref;
        struct completion done;
        enum memory_type type;
        unsigned int flags;
@@ -191,7 +179,7 @@ static inline unsigned long memremap_compat_align(void)
 static inline void put_dev_pagemap(struct dev_pagemap *pgmap)
 {
        if (pgmap)
-               percpu_ref_put(pgmap->ref);
+               percpu_ref_put(&pgmap->ref);
 }
 
 #endif /* _LINUX_MEMREMAP_H_ */

diff --git a/mm/memremap.c b/mm/memremap.c
index 5a66a71..643965d 100644 (file)
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -112,30 +112,6 @@ static unsigned long pfn_next(unsigned long pfn)
 #define for_each_device_pfn(pfn, map, i) \
        for (pfn = pfn_first(map, i); pfn < pfn_end(map, i); pfn = pfn_next(pfn))
 
-static void dev_pagemap_kill(struct dev_pagemap *pgmap)
-{
-       if (pgmap->ops && pgmap->ops->kill)
-               pgmap->ops->kill(pgmap);
-       else
-               percpu_ref_kill(pgmap->ref);
-}
-
-static void dev_pagemap_cleanup(struct dev_pagemap *pgmap)
-{
-       if (pgmap->ops && pgmap->ops->cleanup) {
-               pgmap->ops->cleanup(pgmap);
-       } else {
-               wait_for_completion(&pgmap->done);
-               percpu_ref_exit(pgmap->ref);
-       }
-       /*
-        * Undo the pgmap ref assignment for the internal case as the
-        * caller may re-enable the same pgmap.
-        */
-       if (pgmap->ref == &pgmap->internal_ref)
-               pgmap->ref = NULL;
-}
-
 static void pageunmap_range(struct dev_pagemap *pgmap, int range_id)
 {
        struct range *range = &pgmap->ranges[range_id];
@@ -167,11 +143,12 @@ void memunmap_pages(struct dev_pagemap *pgmap)
        unsigned long pfn;
        int i;
 
-       dev_pagemap_kill(pgmap);
+       percpu_ref_kill(&pgmap->ref);
        for (i = 0; i < pgmap->nr_range; i++)
                for_each_device_pfn(pfn, pgmap, i)
                        put_page(pfn_to_page(pfn));
-       dev_pagemap_cleanup(pgmap);
+       wait_for_completion(&pgmap->done);
+       percpu_ref_exit(&pgmap->ref);
 
        for (i = 0; i < pgmap->nr_range; i++)
                pageunmap_range(pgmap, i);
@@ -188,8 +165,7 @@ static void devm_memremap_pages_release(void *data)
 
 static void dev_pagemap_percpu_release(struct percpu_ref *ref)
 {
-       struct dev_pagemap *pgmap =
-               container_of(ref, struct dev_pagemap, internal_ref);
+       struct dev_pagemap *pgmap = container_of(ref, struct dev_pagemap, ref);
 
        complete(&pgmap->done);
 }
@@ -295,8 +271,8 @@ static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params,
        memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],
                                PHYS_PFN(range->start),
                                PHYS_PFN(range_len(range)), pgmap);
-       percpu_ref_get_many(pgmap->ref, pfn_end(pgmap, range_id)
-                       - pfn_first(pgmap, range_id));
+       percpu_ref_get_many(&pgmap->ref,
+               pfn_end(pgmap, range_id) - pfn_first(pgmap, range_id));
        return 0;
 
 err_add_memory:
@@ -362,22 +338,11 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid)
                break;
        }
 
-       if (!pgmap->ref) {
-               if (pgmap->ops && (pgmap->ops->kill || pgmap->ops->cleanup))
-                       return ERR_PTR(-EINVAL);
-
-               init_completion(&pgmap->done);
-               error = percpu_ref_init(&pgmap->internal_ref,
-                               dev_pagemap_percpu_release, 0, GFP_KERNEL);
-               if (error)
-                       return ERR_PTR(error);
-               pgmap->ref = &pgmap->internal_ref;
-       } else {
-               if (!pgmap->ops || !pgmap->ops->kill || !pgmap->ops->cleanup) {
-                       WARN(1, "Missing reference count teardown definition\n");
-                       return ERR_PTR(-EINVAL);
-               }
-       }
+       init_completion(&pgmap->done);
+       error = percpu_ref_init(&pgmap->ref, dev_pagemap_percpu_release, 0,
+                               GFP_KERNEL);
+       if (error)
+               return ERR_PTR(error);
 
        devmap_managed_enable_get(pgmap);
 
@@ -486,7 +451,7 @@ struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
        /* fall back to slow path lookup */
        rcu_read_lock();
        pgmap = xa_load(&pgmap_array, PHYS_PFN(phys));
-       if (pgmap && !percpu_ref_tryget_live(pgmap->ref))
+       if (pgmap && !percpu_ref_tryget_live(&pgmap->ref))
                pgmap = NULL;
        rcu_read_unlock();
 

diff --git a/tools/testing/nvdimm/test/iomap.c b/tools/testing/nvdimm/test/iomap.c
index ed563bd..b752ce4 100644 (file)
--- a/tools/testing/nvdimm/test/iomap.c
+++ b/tools/testing/nvdimm/test/iomap.c
@@ -100,25 +100,17 @@ static void nfit_test_kill(void *_pgmap)
 {
        struct dev_pagemap *pgmap = _pgmap;
 
-       WARN_ON(!pgmap || !pgmap->ref);
-
-       if (pgmap->ops && pgmap->ops->kill)
-               pgmap->ops->kill(pgmap);
-       else
-               percpu_ref_kill(pgmap->ref);
-
-       if (pgmap->ops && pgmap->ops->cleanup) {
-               pgmap->ops->cleanup(pgmap);
-       } else {
-               wait_for_completion(&pgmap->done);
-               percpu_ref_exit(pgmap->ref);
-       }
+       WARN_ON(!pgmap);
+
+       percpu_ref_kill(&pgmap->ref);
+
+       wait_for_completion(&pgmap->done);
+       percpu_ref_exit(&pgmap->ref);
 }
 
 static void dev_pagemap_percpu_release(struct percpu_ref *ref)
 {
-       struct dev_pagemap *pgmap =
-               container_of(ref, struct dev_pagemap, internal_ref);
+       struct dev_pagemap *pgmap = container_of(ref, struct dev_pagemap, ref);
 
        complete(&pgmap->done);
 }
@@ -132,22 +124,11 @@ void *__wrap_devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
        if (!nfit_res)
                return devm_memremap_pages(dev, pgmap);
 
-       if (!pgmap->ref) {
-               if (pgmap->ops && (pgmap->ops->kill || pgmap->ops->cleanup))
-                       return ERR_PTR(-EINVAL);
-
-               init_completion(&pgmap->done);
-               error = percpu_ref_init(&pgmap->internal_ref,
-                               dev_pagemap_percpu_release, 0, GFP_KERNEL);
-               if (error)
-                       return ERR_PTR(error);
-               pgmap->ref = &pgmap->internal_ref;
-       } else {
-               if (!pgmap->ops || !pgmap->ops->kill || !pgmap->ops->cleanup) {
-                       WARN(1, "Missing reference count teardown definition\n");
-                       return ERR_PTR(-EINVAL);
-               }
-       }
+       init_completion(&pgmap->done);
+       error = percpu_ref_init(&pgmap->ref, dev_pagemap_percpu_release, 0,
+                               GFP_KERNEL);
+       if (error)
+               return ERR_PTR(error);
 
        error = devm_add_action_or_reset(dev, nfit_test_kill, pgmap);
        if (error)