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Commit f3c9a1ab authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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
parents 29dde7c2 0a370d26

drivers/nvdimm/pmem.c

+14 −0
Original line number Diff line number Diff line
@@ -103,6 +103,20 @@ static int pmem_do_bvec(struct pmem_device *pmem, struct page *page, 
			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)) {

include/linux/pmem.h

+16 −6
Original line number Diff line number Diff line
@@ -72,6 +72,18 @@ static inline void arch_invalidate_pmem(void __pmem *addr, size_t size) 
}

#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 void arch_invalidate_pmem(void __pmem *addr, size_t size) 
static inline int memcpy_from_pmem(void *dst, void __pmem const *src,

		size_t size)

{

	if (arch_has_pmem_api())

		return arch_memcpy_from_pmem(dst, src, size);

}



static inline bool arch_has_pmem_api(void)

{

	return IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API);

	else

		return default_memcpy_from_pmem(dst, src, size);

}



/**