Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm fixes from Ross Zwisler:
"Two fixes:
- Fix memcpy_from_pmem() to fallback to memcpy() for architectures
where CONFIG_ARCH_HAS_PMEM_API=n.
- Add a comment explaining why we write data twice when clearing
poison in pmem_do_bvec().
This has passed a boot test on an X86_32 config, which was the
architecture where issue #1 above was first noticed"
Dan Williams adds:
"We're giving this multi-maintainer setup a shot, so expect libnvdimm
pull requests from either Ross or I going forward"
* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
libnvdimm, pmem: clarify the write+clear_poison+write flow
pmem: fix BUG() error in pmem.h:48 on X86_32
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 8e09c54..f798899 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -103,6 +103,20 @@
flush_dcache_page(page);
}
} else {
+ /*
+ * Note that we write the data both before and after
+ * clearing poison. The write before clear poison
+ * handles situations where the latest written data is
+ * preserved and the clear poison operation simply marks
+ * the address range as valid without changing the data.
+ * In this case application software can assume that an
+ * interrupted write will either return the new good
+ * data or an error.
+ *
+ * However, if pmem_clear_poison() leaves the data in an
+ * indeterminate state we need to perform the write
+ * after clear poison.
+ */
flush_dcache_page(page);
memcpy_to_pmem(pmem_addr, mem + off, len);
if (unlikely(bad_pmem)) {
diff --git a/include/linux/pmem.h b/include/linux/pmem.h
index ac6d872..57d146f 100644
--- a/include/linux/pmem.h
+++ b/include/linux/pmem.h
@@ -72,6 +72,18 @@
}
#endif
+static inline bool arch_has_pmem_api(void)
+{
+ return IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API);
+}
+
+static inline int default_memcpy_from_pmem(void *dst, void __pmem const *src,
+ size_t size)
+{
+ memcpy(dst, (void __force *) src, size);
+ return 0;
+}
+
/*
* memcpy_from_pmem - read from persistent memory with error handling
* @dst: destination buffer
@@ -83,12 +95,10 @@
static inline int memcpy_from_pmem(void *dst, void __pmem const *src,
size_t size)
{
- return arch_memcpy_from_pmem(dst, src, size);
-}
-
-static inline bool arch_has_pmem_api(void)
-{
- return IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API);
+ if (arch_has_pmem_api())
+ return arch_memcpy_from_pmem(dst, src, size);
+ else
+ return default_memcpy_from_pmem(dst, src, size);
}
/**