The patch titled
Subject: mm, devm_memremap_pages: handle errors allocating final devres action
has been added to the -mm tree. Its filename is
mm-devm_memremap_pages-handle-errors-allocating-final-devres-action.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-devm_memremap_pages-handle-errors-allocating-final-devres-action.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-devm_memremap_pages-handle-errors-allocating-final-devres-action.patch
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------------------------------------------------------
From: Dan Williams <dan.j.williams@xxxxxxxxx>
Subject: mm, devm_memremap_pages: handle errors allocating final devres action
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.
Link: http://lkml.kernel.org/r/152694212460.5484.13180030631810166467.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: e8d513483300 ("memremap: change devm_memremap_pages interface...")
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: "Jérôme Glisse" <jglisse@xxxxxxxxxx>
Cc: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/memremap.h | 1 +
kernel/memremap.c | 8 ++++++--
2 files changed, 7 insertions(+), 2 deletions(-)
diff -puN include/linux/memremap.h~mm-devm_memremap_pages-handle-errors-allocating-final-devres-action include/linux/memremap.h
--- a/include/linux/memremap.h~mm-devm_memremap_pages-handle-errors-allocating-final-devres-action
+++ a/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 -puN kernel/memremap.c~mm-devm_memremap_pages-handle-errors-allocating-final-devres-action kernel/memremap.c
--- a/kernel/memremap.c~mm-devm_memremap_pages-handle-errors-allocating-final-devres-action
+++ a/kernel/memremap.c
@@ -296,7 +296,7 @@ static void devm_memremap_pages_release(
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
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);
_
Patches currently in -mm which might be from dan.j.williams@xxxxxxxxx are
mm-devm_memremap_pages-mark-devm_memremap_pages-export_symbol_gpl.patch
mm-devm_memremap_pages-handle-errors-allocating-final-devres-action.patch
mm-hmm-use-devm-semantics-for-hmm_devmem_add-remove.patch
mm-hmm-replace-hmm_devmem_pages_create-with-devm_memremap_pages.patch
mm-hmm-mark-hmm_devmem_add-add_resource-export_symbol_gpl.patch
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