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@intel.com 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@dwilli... Fixes: e8d513483300 ("memremap: change devm_memremap_pages interface...") Signed-off-by: Dan Williams dan.j.williams@intel.com Reviewed-by: Christoph Hellwig hch@lst.de Cc: "Jérôme Glisse" jglisse@redhat.com Cc: Logan Gunthorpe logang@deltatee.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

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@intel.com 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