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| author |   Dan Williams <dan.j.williams@intel.com> | 2018-05-03 17:06:21 -0700 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2018-05-15 08:32:42 +0200 |
| commit | 60622d68227d6d71fdfba5fb39f7f3d44cdd8815 (patch) | |
| tree | 345ff9c60d43d8d3720053a25f855289cd9570ff /include/linux/string.h | |
| parent | x86/asm/memcpy_mcsafe: Add labels for __memcpy_mcsafe() write fault handling (diff) | |
| download | wireguard-linux-60622d68227d6d71fdfba5fb39f7f3d44cdd8815.tar.xz wireguard-linux-60622d68227d6d71fdfba5fb39f7f3d44cdd8815.zip | |
x86/asm/memcpy_mcsafe: Return bytes remaining
Machine check safe memory copies are currently deployed in the pmem
driver whenever reading from persistent memory media, so that -EIO is
returned rather than triggering a kernel panic. While this protects most
pmem accesses, it is not complete in the filesystem-dax case. When
filesystem-dax is enabled reads may bypass the block layer and the
driver via dax_iomap_actor() and its usage of copy_to_iter().
In preparation for creating a copy_to_iter() variant that can handle
machine checks, teach memcpy_mcsafe() to return the number of bytes
remaining rather than -EFAULT when an exception occurs.
Co-developed-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: hch@lst.de
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-nvdimm@lists.01.org
Link: http://lkml.kernel.org/r/152539238119.31796.14318473522414462886.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/string.h')
| -rw-r--r-- | include/linux/string.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/string.h b/include/linux/string.h index dd39a690c841..4a5a0eb7df51 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -147,8 +147,8 @@ extern int memcmp(const void *,const void *,__kernel_size_t); 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) +static inline __must_check unsigned long memcpy_mcsafe(void *dst, + const void *src, size_t cnt) { memcpy(dst, src, cnt); return 0; |