filesystem-dax: convert to dax_copy_from_iter()

Now that all possible providers of the dax_operations copy_from_iter
method are implemented, switch filesytem-dax to call the driver rather
than copy_to_iter_pmem.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

arch/x86/include/asm/pmem.h

@@ -65,56 +65,6 @@ static inline void arch_wb_cache_pmem(void *addr, size_t size)
 		clwb(p);
 }
 
-/**
- * arch_copy_from_iter_pmem - copy data from an iterator to PMEM
- * @addr:	PMEM destination address
- * @bytes:	number of bytes to copy
- * @i:		iterator with source data
- *
- * Copy data from the iterator 'i' to the PMEM buffer starting at 'addr'.
- */
-static inline size_t arch_copy_from_iter_pmem(void *addr, size_t bytes,
-		struct iov_iter *i)
-{
-	size_t len;
-
-	/* TODO: skip the write-back by always using non-temporal stores */
-	len = copy_from_iter_nocache(addr, bytes, i);
-
-	/*
-	 * In the iovec case on x86_64 copy_from_iter_nocache() uses
-	 * non-temporal stores for the bulk of the transfer, but we need
-	 * to manually flush if the transfer is unaligned. A cached
-	 * memory copy is used when destination or size is not naturally
-	 * aligned. That is:
-	 *   - Require 8-byte alignment when size is 8 bytes or larger.
-	 *   - Require 4-byte alignment when size is 4 bytes.
-	 *
-	 * In the non-iovec case the entire destination needs to be
-	 * flushed.
-	 */
-	if (iter_is_iovec(i)) {
-		unsigned long flushed, dest = (unsigned long) addr;
-
-		if (bytes < 8) {
-			if (!IS_ALIGNED(dest, 4) || (bytes != 4))
-				arch_wb_cache_pmem(addr, bytes);
-		} else {
-			if (!IS_ALIGNED(dest, 8)) {
-				dest = ALIGN(dest, boot_cpu_data.x86_clflush_size);
-				arch_wb_cache_pmem(addr, 1);
-			}
-
-			flushed = dest - (unsigned long) addr;
-			if (bytes > flushed && !IS_ALIGNED(bytes - flushed, 8))
-				arch_wb_cache_pmem(addr + bytes - 1, 1);
-		}
-	} else
-		arch_wb_cache_pmem(addr, bytes);
-
-	return len;
-}
-
 /**
  * arch_clear_pmem - zero a PMEM memory range
  * @addr:	virtual start address

fs/dax.c

@@ -1054,7 +1054,8 @@ dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 			map_len = end - pos;
 
 		if (iov_iter_rw(iter) == WRITE)
-			map_len = copy_from_iter_pmem(kaddr, map_len, iter);
+			map_len = dax_copy_from_iter(dax_dev, pgoff, kaddr,
+					map_len, iter);
 		else
 			map_len = copy_to_iter(kaddr, map_len, iter);
 		if (map_len <= 0) {

include/linux/pmem.h

@@ -31,13 +31,6 @@ static inline void arch_memcpy_to_pmem(void *dst, const void *src, size_t n)
 	BUG();
 }
 
-static inline size_t arch_copy_from_iter_pmem(void *addr, size_t bytes,
-		struct iov_iter *i)
-{
-	BUG();
-	return 0;
-}
-
 static inline void arch_clear_pmem(void *addr, size_t size)
 {
 	BUG();
@@ -79,23 +72,6 @@ static inline void memcpy_to_pmem(void *dst, const void *src, size_t n)
 		memcpy(dst, src, n);
 }
 
-/**
- * copy_from_iter_pmem - copy data from an iterator to PMEM
- * @addr:	PMEM destination address
- * @bytes:	number of bytes to copy
- * @i:		iterator with source data
- *
- * Copy data from the iterator 'i' to the PMEM buffer starting at 'addr'.
- * See blkdev_issue_flush() note for memcpy_to_pmem().
- */
-static inline size_t copy_from_iter_pmem(void *addr, size_t bytes,
-		struct iov_iter *i)
-{
-	if (arch_has_pmem_api())
-		return arch_copy_from_iter_pmem(addr, bytes, i);
-	return copy_from_iter_nocache(addr, bytes, i);
-}
-
 /**
  * clear_pmem - zero a PMEM memory range
  * @addr:	virtual start address