path: root/kernel/memremap.c
diff options
authorLinus Torvalds <torvalds@linux-foundation.org>2015-11-01 14:13:54 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-01 14:13:54 -0800
commit95fc00a4e15e804356d01c1c53c7da3d99a94f20 (patch)
treeffbfd0bf22ba6c830f1485fe4833cdd47bc80654 /kernel/memremap.c
parentca04d396a3229d37d8151311ad70d1255a5807bd (diff)
parent182475b7a2831abf7e6ca83b2aced0bef5dcdfd3 (diff)
Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull memremap fix from Dan Williams: "The new memremap() api introduced in the 4.3 cycle to unify/replace ioremap_cache() and ioremap_wt() is mishandling the highmem case. This patch has received a build success notification from a 0day-kbuild-robot run and has received an ack from Ard" From the commit message: "The impact of this bug is low for now since the pmem driver is the only user of memremap(), but this is important to fix before more conversions to memremap arrive in 4.4" * 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: memremap: fix highmem support
Diffstat (limited to 'kernel/memremap.c')
1 files changed, 12 insertions, 2 deletions
diff --git a/kernel/memremap.c b/kernel/memremap.c
index 72b0c66628b6..9d6b55587eaa 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -24,6 +24,16 @@ __weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)
+static void *try_ram_remap(resource_size_t offset, size_t size)
+ struct page *page = pfn_to_page(offset >> PAGE_SHIFT);
+ /* In the simple case just return the existing linear address */
+ if (!PageHighMem(page))
+ return __va(offset);
+ return NULL; /* fallback to ioremap_cache */
* memremap() - remap an iomem_resource as cacheable memory
* @offset: iomem resource start address
@@ -66,8 +76,8 @@ void *memremap(resource_size_t offset, size_t size, unsigned long flags)
* the requested range is potentially in "System RAM"
if (is_ram == REGION_INTERSECTS)
- addr = __va(offset);
- else
+ addr = try_ram_remap(offset, size);
+ if (!addr)
addr = ioremap_cache(offset, size);