The patch titled
Subject: mm, devm_memremap_pages: handle errors allocating final devres action
has been removed from the -mm tree. Its filename was
mm-devm_memremap_pages-handle-errors-allocating-final-devres-action.patch
This patch was dropped because an updated version will be merged
------------------------------------------------------
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.
Without this change we could fail to register the teardown of
devm_memremap_pages(). The likelihood of hitting this failure is tiny
as small memory allocations almost always succeed. However, the impact
of the failure is large given any future reconfiguration, or
disable/enable, of an nvdimm namespace will fail forever as subsequent
calls to devm_memremap_pages() will fail to setup the pgmap_radix since
there will be stale entries for the physical address range.
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>
Reviewed-by: 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
@@ -124,7 +124,7 @@ 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);
}
@@ -246,7 +246,11 @@ 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-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
