gfs2: Replace deprecated kmap_atomic with kmap_local_page

kmap_atomic() is deprecated in favor of kmap_local_{folio,page}().

Therefore, replace kmap_atomic() with kmap_local_page() in
gfs2_internal_read() and stuffed_readpage().

kmap_atomic() disables page-faults and preemption (the latter only for
!PREEMPT_RT kernels), However, the code within the mapping/un-mapping in
gfs2_internal_read() and stuffed_readpage() does not depend on the
above-mentioned side effects.

Therefore, a mere replacement of the old API with the new one is all that
is required (i.e., there is no need to explicitly add any calls to
pagefault_disable() and/or preempt_disable()).

Signed-off-by: Deepak R Varma <[email protected]>
Signed-off-by: Andreas Gruenbacher <[email protected]>

fs/gfs2/aops.c

@@ -431,10 +431,10 @@ static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
 	if (error)
 		return error;
 
-	kaddr = kmap_atomic(page);
+	kaddr = kmap_local_page(page);
 	memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), dsize);
 	memset(kaddr + dsize, 0, PAGE_SIZE - dsize);
-	kunmap_atomic(kaddr);
+	kunmap_local(kaddr);
 	flush_dcache_page(page);
 	brelse(dibh);
 	SetPageUptodate(page);
@@ -497,12 +497,12 @@ int gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos,
 				continue;
 			return PTR_ERR(page);
 		}
-		p = kmap_atomic(page);
+		p = kmap_local_page(page);
 		amt = size - copied;
 		if (offset + size > PAGE_SIZE)
 			amt = PAGE_SIZE - offset;
 		memcpy(buf + copied, p + offset, amt);
-		kunmap_atomic(p);
+		kunmap_local(p);
 		put_page(page);
 		copied += amt;
 		index++;