f2fs: use memcpy_{to,from}_page() where possible

This is simpler, and as a side effect it replaces several uses of
kmap_atomic() with its recommended replacement kmap_local_page().

Signed-off-by: Eric Biggers <[e-mail]>
Reviewed-by: Fabio M. De Francesco <[e-mail]>
Reviewed-by: Chao Yu <[e-mail]>
Signed-off-by: Jaegeuk Kim <[e-mail]>

fs/f2fs/inline.c

···
 void f2fs_do_read_inline_data(struct page *page, struct page *ipage)
 {
 	struct inode *inode = page->mapping->host;
-	void *src_addr, *dst_addr;
 
 	if (PageUptodate(page))
 		return;
···
 	zero_user_segment(page, MAX_INLINE_DATA(inode), PAGE_SIZE);
 
 	/* Copy the whole inline data block */
-	src_addr = inline_data_addr(inode, ipage);
-	dst_addr = kmap_atomic(page);
-	memcpy(dst_addr, src_addr, MAX_INLINE_DATA(inode));
-	flush_dcache_page(page);
-	kunmap_atomic(dst_addr);
+	memcpy_to_page(page, 0, inline_data_addr(inode, ipage),
+		       MAX_INLINE_DATA(inode));
 	if (!PageUptodate(page))
 		SetPageUptodate(page);
 }
···
 
 int f2fs_write_inline_data(struct inode *inode, struct page *page)
 {
-	void *src_addr, *dst_addr;
 	struct dnode_of_data dn;
 	int err;
 
···
 	f2fs_bug_on(F2FS_I_SB(inode), page->index);
 
 	f2fs_wait_on_page_writeback(dn.inode_page, NODE, true, true);
-	src_addr = kmap_atomic(page);
-	dst_addr = inline_data_addr(inode, dn.inode_page);
-	memcpy(dst_addr, src_addr, MAX_INLINE_DATA(inode));
-	kunmap_atomic(src_addr);
+	memcpy_from_page(inline_data_addr(inode, dn.inode_page),
+			 page, 0, MAX_INLINE_DATA(inode));
 	set_page_dirty(dn.inode_page);
 
 	f2fs_clear_page_cache_dirty_tag(page);

fs/f2fs/super.c

···
 	size_t toread;
 	loff_t i_size = i_size_read(inode);
 	struct page *page;
-	char *kaddr;
 
 	if (off > i_size)
 		return 0;
···
 			return -EIO;
 		}
 
-		kaddr = kmap_atomic(page);
-		memcpy(data, kaddr + offset, tocopy);
-		kunmap_atomic(kaddr);
+		memcpy_from_page(data, page, offset, tocopy);
 		f2fs_put_page(page, 1);
 
 		offset = 0;
···
 	size_t towrite = len;
 	struct page *page;
 	void *fsdata = NULL;
-	char *kaddr;
 	int err = 0;
 	int tocopy;
 
···
 			break;
 		}
 
-		kaddr = kmap_atomic(page);
-		memcpy(kaddr + offset, data, tocopy);
-		kunmap_atomic(kaddr);
-		flush_dcache_page(page);
+		memcpy_to_page(page, offset, data, tocopy);
 
 		a_ops->write_end(NULL, mapping, off, tocopy, tocopy,
 						page, fsdata);

fs/f2fs/verity.c

···
 		size_t n = min_t(size_t, count,
 				 PAGE_SIZE - offset_in_page(pos));
 		struct page *page;
-		void *addr;
 
 		page = read_mapping_page(inode->i_mapping, pos >> PAGE_SHIFT,
 					 NULL);
 		if (IS_ERR(page))
 			return PTR_ERR(page);
 
-		addr = kmap_atomic(page);
-		memcpy(buf, addr + offset_in_page(pos), n);
-		kunmap_atomic(addr);
+		memcpy_from_page(buf, page, offset_in_page(pos), n);
 
 		put_page(page);
 
···
 				 PAGE_SIZE - offset_in_page(pos));
 		struct page *page;
 		void *fsdata;
-		void *addr;
 		int res;
 
 		res = aops->write_begin(NULL, mapping, pos, n, &page, &fsdata);
 		if (res)
 			return res;
 
-		addr = kmap_atomic(page);
-		memcpy(addr + offset_in_page(pos), buf, n);
-		kunmap_atomic(addr);
+		memcpy_to_page(page, offset_in_page(pos), buf, n);
 
 		res = aops->write_end(NULL, mapping, pos, n, n, page, fsdata);
 		if (res < 0)