diff options
authorDan Williams <>2019-06-13 15:56:18 -0700
committerLinus Torvalds <>2019-06-13 17:34:56 -1000
commit2374b682255184d7ef75fcb507ce5af4995ead32 (patch)
parenta58f2cef26e1ca44182c8b22f4f4395e702a5795 (diff)
drivers/base/devres: introduce devm_release_action()
Patch series "mm/devm_memremap_pages: Fix page release race", v2. Logan audited the devm_memremap_pages() shutdown path and noticed that it was possible to proceed to arch_remove_memory() before all potential page references have been reaped. Introduce a new ->cleanup() callback to do the work of waiting for any straggling page references and then perform the percpu_ref_exit() in devm_memremap_pages_release() context. For p2pdma this involves some deeper reworks to reference count resources on a per-instance basis rather than a per pci-device basis. A modified genalloc api is introduced to convey a driver-private pointer through gen_pool_{alloc,free}() interfaces. Also, a devm_memunmap_pages() api is introduced since p2pdma does not auto-release resources on a setup failure. The dax and pmem changes pass the nvdimm unit tests, and the p2pdma changes should now pass testing with the pci_p2pdma_release() fix. Jrme, how does this look for HMM? This patch (of 6): The devm_add_action() facility allows a resource allocation routine to add custom devm semantics. One such user is devm_memremap_pages(). There is now a need to manually trigger devm_memremap_pages_release(). Introduce devm_release_action() so the release action can be triggered via a new devm_memunmap_pages() api in a follow-on change. Link: Signed-off-by: Dan Williams <> Reviewed-by: Ira Weiny <> Reviewed-by: Logan Gunthorpe <> Cc: Bjorn Helgaas <> Cc: Christoph Hellwig <> Cc: Greg Kroah-Hartman <> Cc: "Rafael J. Wysocki" <> Cc: "Jérôme Glisse" <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2 files changed, 24 insertions, 1 deletions
diff --git a/drivers/base/devres.c b/drivers/base/devres.c
index e038e2b3b7ea..0bbb328bd17f 100644
--- a/drivers/base/devres.c
+++ b/drivers/base/devres.c
@@ -755,10 +755,32 @@ void devm_remove_action(struct device *dev, void (*action)(void *), void *data)
WARN_ON(devres_destroy(dev, devm_action_release, devm_action_match,
+ * devm_release_action() - release previously added custom action
+ * @dev: Device that owns the action
+ * @action: Function implementing the action
+ * @data: Pointer to data passed to @action implementation
+ *
+ * Releases and removes instance of @action previously added by
+ * devm_add_action(). Both action and data should match one of the
+ * existing entries.
+ */
+void devm_release_action(struct device *dev, void (*action)(void *), void *data)
+ struct action_devres devres = {
+ .data = data,
+ .action = action,
+ };
+ WARN_ON(devres_release(dev, devm_action_release, devm_action_match,
+ &devres));
* Managed kmalloc/kfree
diff --git a/include/linux/device.h b/include/linux/device.h
index e85264fb6616..848fc71c6ba6 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -713,6 +713,7 @@ void __iomem *devm_of_iomap(struct device *dev,
/* allows to add/remove a custom action to devres stack */
int devm_add_action(struct device *dev, void (*action)(void *), void *data);
void devm_remove_action(struct device *dev, void (*action)(void *), void *data);
+void devm_release_action(struct device *dev, void (*action)(void *), void *data);
static inline int devm_add_action_or_reset(struct device *dev,
void (*action)(void *), void *data)