diff options
| 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 /drivers/nvdimm/pmem.c | |
| parent | bd131544aa7e318a5735cbcbad46c4a5ee6b9d42 (diff) | |
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 'drivers/nvdimm/pmem.c')
| -rw-r--r-- | drivers/nvdimm/pmem.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c index 9d714926ecf5..e023d6aa22b5 100644 --- a/drivers/nvdimm/pmem.c +++ b/drivers/nvdimm/pmem.c @@ -101,15 +101,15 @@ static blk_status_t read_pmem(struct page *page, unsigned int off, void *pmem_addr, unsigned int len) { unsigned int chunk; - int rc; + unsigned long rem; void *mem; while (len) { mem = kmap_atomic(page); chunk = min_t(unsigned int, len, PAGE_SIZE); - rc = memcpy_mcsafe(mem + off, pmem_addr, chunk); + rem = memcpy_mcsafe(mem + off, pmem_addr, chunk); kunmap_atomic(mem); - if (rc) + if (rem) return BLK_STS_IOERR; len -= chunk; off = 0; |