linux-kernel - [PATCH 4/5] memremap: don't use a separate devm action for devmap_managed_enable

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Date:   Sun, 11 Aug 2019 10:12:46 +0200
From:   Christoph Hellwig <hch@....de>
To:     Dan Williams <dan.j.williams@...el.com>,
        Jason Gunthorpe <jgg@...lanox.com>
Cc:     Bharata B Rao <bharata@...ux.ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, linux-nvdimm@...ts.01.org
Subject: [PATCH 4/5] memremap: don't use a separate devm action for devmap_managed_enable_get

Just clean up for early failures and then piggy back on
devm_memremap_pages_release.  This helps with a pending not device
managed version of devm_memremap_pages.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 mm/memremap.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/mm/memremap.c b/mm/memremap.c
index 600a14cbe663..09a087ca30ff 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -21,13 +21,13 @@ 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)
+static void devmap_managed_enable_put(void)
 {
 	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)
+static int devmap_managed_enable_get(struct dev_pagemap *pgmap)
 {
 	if (!pgmap->ops || !pgmap->ops->page_free) {
 		WARN(1, "Missing page_free method\n");
@@ -36,13 +36,16 @@ static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgm
 
 	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);
+	return 0;
 }
 #else
-static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap)
+static int devmap_managed_enable_get(struct dev_pagemap *pgmap)
 {
 	return -EINVAL;
 }
+static void devmap_managed_enable_put(void)
+{
+}
 #endif /* CONFIG_DEV_PAGEMAP_OPS */
 
 static void pgmap_array_delete(struct resource *res)
@@ -123,6 +126,7 @@ static void devm_memremap_pages_release(void *data)
 	untrack_pfn(NULL, PHYS_PFN(res->start), resource_size(res));
 	pgmap_array_delete(res);
 	WARN_ONCE(pgmap->altmap.alloc, "failed to free all reserved pages\n");
+	devmap_managed_enable_put();
 }
 
 static void dev_pagemap_percpu_release(struct percpu_ref *ref)
@@ -212,7 +216,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
 	}
 
 	if (need_devmap_managed) {
-		error = devmap_managed_enable_get(dev, pgmap);
+		error = devmap_managed_enable_get(pgmap);
 		if (error)
 			return ERR_PTR(error);
 	}
@@ -321,6 +325,7 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
  err_array:
 	dev_pagemap_kill(pgmap);
 	dev_pagemap_cleanup(pgmap);
+	devmap_managed_enable_put();
 	return ERR_PTR(error);
 }
 EXPORT_SYMBOL_GPL(devm_memremap_pages);
-- 
2.20.1