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Subject[PATCH 01/13] x86, dax, pmem: remove indirection around memcpy_from_pmem()
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memcpy_from_pmem() maps directly to memcpy_mcsafe(). The wrapper
serves no real benefit aside from affording a more generic function name
than the x86-specific 'mcsafe'. However this would not be the first time
that x86 terminology leaked into the global namespace. For lack of
better name, just use memcpy_mcsafe() directly.

This conversion also catches places where we were failing to check the
return value, read_dax_sector(), or where we should have been using
plain memcpy, acpi_nfit_blk_single_io().

Cc: <x86@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
arch/x86/include/asm/pmem.h | 5 -----
arch/x86/include/asm/string_64.h | 1 +
drivers/acpi/nfit/core.c | 3 +--
drivers/nvdimm/claim.c | 2 +-
drivers/nvdimm/pmem.c | 2 +-
fs/dax.c | 8 +++++++-
include/linux/pmem.h | 23 -----------------------
include/linux/string.h | 8 ++++++++
8 files changed, 19 insertions(+), 33 deletions(-)

diff --git a/arch/x86/include/asm/pmem.h b/arch/x86/include/asm/pmem.h
index 2c1ebeb4d737..f26ba430d853 100644
--- a/arch/x86/include/asm/pmem.h
+++ b/arch/x86/include/asm/pmem.h
@@ -44,11 +44,6 @@ static inline void arch_memcpy_to_pmem(void *dst, const void *src, size_t n)
BUG();
}

-static inline int arch_memcpy_from_pmem(void *dst, const void *src, size_t n)
-{
- return memcpy_mcsafe(dst, src, n);
-}
-
/**
* arch_wb_cache_pmem - write back a cache range with CLWB
* @vaddr: virtual start address
diff --git a/arch/x86/include/asm/string_64.h b/arch/x86/include/asm/string_64.h
index a164862d77e3..733bae07fb29 100644
--- a/arch/x86/include/asm/string_64.h
+++ b/arch/x86/include/asm/string_64.h
@@ -79,6 +79,7 @@ int strcmp(const char *cs, const char *ct);
#define memset(s, c, n) __memset(s, c, n)
#endif

+#define __HAVE_ARCH_MEMCPY_MCSAFE 1
__must_check int memcpy_mcsafe_unrolled(void *dst, const void *src, size_t cnt);
DECLARE_STATIC_KEY_FALSE(mcsafe_key);

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 2f82b8eba360..2019de7b84e5 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -1765,8 +1765,7 @@ static int acpi_nfit_blk_single_io(struct nfit_blk *nfit_blk,
mmio_flush_range((void __force *)
mmio->addr.aperture + offset, c);

- memcpy_from_pmem(iobuf + copied,
- mmio->addr.aperture + offset, c);
+ memcpy(iobuf + copied, mmio->addr.aperture + offset, c);
}

copied += c;
diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c
index b3323c0697f6..61293504b52c 100644
--- a/drivers/nvdimm/claim.c
+++ b/drivers/nvdimm/claim.c
@@ -239,7 +239,7 @@ static int nsio_rw_bytes(struct nd_namespace_common *ndns,
if (rw == READ) {
if (unlikely(is_bad_pmem(&nsio->bb, sector, sz_align)))
return -EIO;
- return memcpy_from_pmem(buf, nsio->addr + offset, size);
+ return memcpy_mcsafe(buf, nsio->addr + offset, size);
}

if (unlikely(is_bad_pmem(&nsio->bb, sector, sz_align))) {
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 7282d7495bf1..0d7779384a9f 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -88,7 +88,7 @@ static int read_pmem(struct page *page, unsigned int off,
int rc;
void *mem = kmap_atomic(page);

- rc = memcpy_from_pmem(mem + off, pmem_addr, len);
+ rc = memcpy_mcsafe(mem + off, pmem_addr, len);
kunmap_atomic(mem);
return rc;
}
diff --git a/fs/dax.c b/fs/dax.c
index ddcddfeaa03b..81a77c070344 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -112,8 +112,14 @@ struct page *read_dax_sector(struct block_device *bdev, sector_t n)
rc = dax_map_atomic(bdev, &dax);
if (rc < 0)
return ERR_PTR(rc);
- memcpy_from_pmem(page_address(page), dax.addr, PAGE_SIZE);
+ rc = memcpy_mcsafe(page_address(page), dax.addr, PAGE_SIZE);
dax_unmap_atomic(bdev, &dax);
+
+ if (rc) {
+ put_page(page);
+ return ERR_PTR(rc);
+ }
+
return page;
}

diff --git a/include/linux/pmem.h b/include/linux/pmem.h
index e856c2cb0fe8..71ecf3d46aac 100644
--- a/include/linux/pmem.h
+++ b/include/linux/pmem.h
@@ -31,12 +31,6 @@ static inline void arch_memcpy_to_pmem(void *dst, const void *src, size_t n)
BUG();
}

-static inline int arch_memcpy_from_pmem(void *dst, const void *src, size_t n)
-{
- BUG();
- return -EFAULT;
-}
-
static inline size_t arch_copy_from_iter_pmem(void *addr, size_t bytes,
struct iov_iter *i)
{
@@ -65,23 +59,6 @@ static inline bool arch_has_pmem_api(void)
return IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API);
}

-/*
- * memcpy_from_pmem - read from persistent memory with error handling
- * @dst: destination buffer
- * @src: source buffer
- * @size: transfer length
- *
- * Returns 0 on success negative error code on failure.
- */
-static inline int memcpy_from_pmem(void *dst, void const *src, size_t size)
-{
- if (arch_has_pmem_api())
- return arch_memcpy_from_pmem(dst, src, size);
- else
- memcpy(dst, src, size);
- return 0;
-}
-
/**
* memcpy_to_pmem - copy data to persistent memory
* @dst: destination buffer for the copy
diff --git a/include/linux/string.h b/include/linux/string.h
index 26b6f6a66f83..9d6f189157e2 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -114,6 +114,14 @@ extern int memcmp(const void *,const void *,__kernel_size_t);
#ifndef __HAVE_ARCH_MEMCHR
extern void * memchr(const void *,int,__kernel_size_t);
#endif
+#ifndef __HAVE_ARCH_MEMCPY_MCSAFE
+static inline __must_check int memcpy_mcsafe(void *dst, const void *src,
+ size_t cnt)
+{
+ memcpy(dst, src, cnt);
+ return 0;
+}
+#endif
void *memchr_inv(const void *s, int c, size_t n);
char *strreplace(char *s, char old, char new);

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