From 36d6cb73d5e60cdb2724c21ccba93c964e6a16f9 Mon Sep 17 00:00:00 2001
From: Anshuman Khandual <anshuman.khandual@arm.com>
Date: Fri, 28 Jun 2019 12:06:37 -0700
Subject: [PATCH] mm/dev_pfn: exclude MEMORY_DEVICE_PRIVATE while computing
virtual address
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The presence of struct page does not guarantee linear mapping for the pfn
physical range. Device private memory which is non-coherent is excluded
from linear mapping during devm_memremap_pages() though they will still
have struct page coverage.
Change pfn_t_to_virt() to just check for device private memory before
giving out virtual address for a given pfn.
pfn_t_to_virt() actually has no callers. Let's fix it for the 5.2 kernel
and remove it in 5.3.
Link: http://lkml.kernel.org/r/1558089514-25067-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
include/linux/pfn_t.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/pfn_t.h b/include/linux/pfn_t.h
index 7bb77850c65ac..3c202a11a79e1 100644
--- a/include/linux/pfn_t.h
+++ b/include/linux/pfn_t.h
@@ -68,7 +68,7 @@ static inline phys_addr_t pfn_t_to_phys(pfn_t pfn)
static inline void *pfn_t_to_virt(pfn_t pfn)
{
- if (pfn_t_has_page(pfn))
+ if (pfn_t_has_page(pfn) && !is_device_private_page(pfn_t_to_page(pfn)))
return __va(pfn_t_to_phys(pfn));
return NULL;
}
--
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