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From: Dan Williams <dan.j.williams@intel.com>
To: akpm@linux-foundation.org
Cc: stable@vger.kernel.org, "Christoph Hellwig" <hch@lst.de>,
	"Jérôme Glisse" <jglisse@redhat.com>,
	"Logan Gunthorpe" <logang@deltatee.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH 2/5] mm, devm_memremap_pages: handle errors allocating final devres action
Date: Mon, 21 May 2018 15:35:24 -0700	[thread overview]
Message-ID: <152694212460.5484.13180030631810166467.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <152694211402.5484.2277538346144115181.stgit@dwillia2-desk3.amr.corp.intel.com>

The last step before devm_memremap_pages() returns success is to
allocate a release action to tear the entire setup down. However, the
result from devm_add_action() is not checked.

Checking the error also means that we need to handle the fact that the
percpu_ref may not be killed by the time devm_memremap_pages_release()
runs. Add a new state flag for this case.

Cc: <stable@vger.kernel.org>
Fixes: e8d513483300 ("memremap: change devm_memremap_pages interface...")
Cc: Christoph Hellwig <hch@lst.de>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 include/linux/memremap.h |    1 +
 kernel/memremap.c        |    8 ++++++--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 7b4899c06f49..44a7ee517513 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -115,6 +115,7 @@ struct dev_pagemap {
 	dev_page_free_t page_free;
 	struct vmem_altmap altmap;
 	bool altmap_valid;
+	bool registered;
 	struct resource res;
 	struct percpu_ref *ref;
 	struct device *dev;
diff --git a/kernel/memremap.c b/kernel/memremap.c
index c614645227a7..30d96be5a965 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -296,7 +296,7 @@ static void devm_memremap_pages_release(void *data)
 	for_each_device_pfn(pfn, pgmap)
 		put_page(pfn_to_page(pfn));
 
-	if (percpu_ref_tryget_live(pgmap->ref)) {
+	if (pgmap->registered && percpu_ref_tryget_live(pgmap->ref)) {
 		dev_WARN(dev, "%s: page mapping is still live!\n", __func__);
 		percpu_ref_put(pgmap->ref);
 	}
@@ -418,7 +418,11 @@ void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
 		percpu_ref_get(pgmap->ref);
 	}
 
-	devm_add_action(dev, devm_memremap_pages_release, pgmap);
+	error = devm_add_action_or_reset(dev, devm_memremap_pages_release,
+			pgmap);
+	if (error)
+		return ERR_PTR(error);
+	pgmap->registered = true;
 
 	return __va(res->start);
 

  parent reply	other threads:[~2018-05-21 22:45 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-21 22:35 [PATCH 0/5] mm: rework hmm to use devm_memremap_pages Dan Williams
2018-05-21 22:35 ` [PATCH 1/5] mm, devm_memremap_pages: mark devm_memremap_pages() EXPORT_SYMBOL_GPL Dan Williams
2018-05-22  6:29   ` Christoph Hellwig
2018-05-21 22:35 ` Dan Williams [this message]
2018-05-21 23:10   ` [PATCH 2/5] mm, devm_memremap_pages: handle errors allocating final devres action Andrew Morton
2018-05-22  0:07     ` Dan Williams
2018-05-22 16:42       ` Logan Gunthorpe
2018-05-22 16:56         ` Dan Williams
2018-05-22 17:03           ` Logan Gunthorpe
2018-05-22 17:25             ` Dan Williams
2018-05-22 17:36               ` Logan Gunthorpe
2018-05-22  6:30   ` Christoph Hellwig
2018-05-21 22:35 ` [PATCH 3/5] mm, hmm: use devm semantics for hmm_devmem_{add, remove} Dan Williams
2018-05-22  6:30   ` Christoph Hellwig
2018-05-21 22:35 ` [PATCH 4/5] mm, hmm: replace hmm_devmem_pages_create() with devm_memremap_pages() Dan Williams
2018-05-22  6:31   ` Christoph Hellwig
2018-05-22 17:13   ` Logan Gunthorpe
2018-05-22 21:38     ` Dan Williams
2018-05-21 22:35 ` [PATCH 5/5] mm, hmm: mark hmm_devmem_{add, add_resource} EXPORT_SYMBOL_GPL Dan Williams
2018-05-22  6:32   ` Christoph Hellwig
2018-05-22 21:31     ` Andrew Morton
2018-06-05 18:24       ` Jerome Glisse
2018-05-24  0:10 ` [PATCH 0/5] mm: rework hmm to use devm_memremap_pages Jerome Glisse
2018-05-24  3:18   ` Dan Williams
2018-05-24  6:35     ` Christoph Hellwig
2018-05-29 22:22     ` Dave Airlie
2018-05-29 22:31       ` Dan Williams
2018-05-29 23:00         ` Dave Airlie
2018-05-29 23:33           ` Dan Williams
2018-06-05 18:48             ` Jerome Glisse
2018-06-05 22:19               ` Dave Airlie
2018-06-05 23:06                 ` Dan Williams
2018-06-06  0:08                   ` Jerome Glisse
2018-06-06  1:33                     ` Dan Williams
2018-06-06  7:14                       ` Christoph Hellwig
2018-06-07 14:16                       ` Jerome Glisse
2018-06-07 18:39                         ` Dan Williams

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