ntfs: Do not kmap pages used for reading from disk

These pages are accessed through DMA and vmap; they are not accessed
by calling page_address(), so they do not need to be kmapped.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

Author: Matthew Wilcox (Oracle)

fs/ntfs3/frecord.c

@@ -2590,7 +2590,6 @@ int ni_read_frame(struct ntfs_inode *ni, u64 frame_vbo, struct page **pages,
 		}
 		pages_disk[i] = pg;
 		lock_page(pg);
-		kmap(pg);
 	}
 
 	/* Read 'ondisk_size' bytes from disk. */
@@ -2640,7 +2639,6 @@ int ni_read_frame(struct ntfs_inode *ni, u64 frame_vbo, struct page **pages,
 	for (i = 0; i < npages_disk; i++) {
 		pg = pages_disk[i];
 		if (pg) {
-			kunmap(pg);
 			unlock_page(pg);
 			put_page(pg);
 		}
@@ -2735,7 +2733,6 @@ int ni_write_frame(struct ntfs_inode *ni, struct page **pages,
 		}
 		pages_disk[i] = pg;
 		lock_page(pg);
-		kmap(pg);
 	}
 
 	/* To simplify compress algorithm do vmap for source and target pages. */
@@ -2823,7 +2820,6 @@ int ni_write_frame(struct ntfs_inode *ni, struct page **pages,
 	for (i = 0; i < pages_per_frame; i++) {
 		pg = pages_disk[i];
 		if (pg) {
-			kunmap(pg);
 			unlock_page(pg);
 			put_page(pg);
 		}