1 files changed, 13 insertions, 6 deletions

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index bc2f700feef8..d9d845077b8b 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -113,13 +113,13 @@ static void write_pmem(void *pmem_addr, struct page *page,
 
 	while (len) {
 		mem = kmap_atomic(page);
-		chunk = min_t(unsigned int, len, PAGE_SIZE);
+		chunk = min_t(unsigned int, len, PAGE_SIZE - off);
 		memcpy_flushcache(pmem_addr, mem + off, chunk);
 		kunmap_atomic(mem);
 		len -= chunk;
 		off = 0;
 		page++;
-		pmem_addr += PAGE_SIZE;
+		pmem_addr += chunk;
 	}
 }
 
@@ -132,7 +132,7 @@ static blk_status_t read_pmem(struct page *page, unsigned int off,
 
 	while (len) {
 		mem = kmap_atomic(page);
-		chunk = min_t(unsigned int, len, PAGE_SIZE);
+		chunk = min_t(unsigned int, len, PAGE_SIZE - off);
 		rem = memcpy_mcsafe(mem + off, pmem_addr, chunk);
 		kunmap_atomic(mem);
 		if (rem)
@@ -140,7 +140,7 @@ static blk_status_t read_pmem(struct page *page, unsigned int off,
 		len -= chunk;
 		off = 0;
 		page++;
-		pmem_addr += PAGE_SIZE;
+		pmem_addr += chunk;
 	}
 	return BLK_STS_OK;
 }
@@ -281,20 +281,27 @@ static long pmem_dax_direct_access(struct dax_device *dax_dev,
 	return __pmem_direct_access(pmem, pgoff, nr_pages, kaddr, pfn);
 }
 
+/*
+ * Use the 'no check' versions of copy_from_iter_flushcache() and
+ * copy_to_iter_mcsafe() to bypass HARDENED_USERCOPY overhead. Bounds
+ * checking, both file offset and device offset, is handled by
+ * dax_iomap_actor()
+ */
 static size_t pmem_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff,
 		void *addr, size_t bytes, struct iov_iter *i)
 {
-	return copy_from_iter_flushcache(addr, bytes, i);
+	return _copy_from_iter_flushcache(addr, bytes, i);
 }
 
 static size_t pmem_copy_to_iter(struct dax_device *dax_dev, pgoff_t pgoff,
 		void *addr, size_t bytes, struct iov_iter *i)
 {
-	return copy_to_iter_mcsafe(addr, bytes, i);
+	return _copy_to_iter_mcsafe(addr, bytes, i);
 }
 
 static const struct dax_operations pmem_dax_ops = {
 	.direct_access = pmem_dax_direct_access,
+	.dax_supported = generic_fsdax_supported,
 	.copy_from_iter = pmem_copy_from_iter,
 	.copy_to_iter = pmem_copy_to_iter,
 };