mm/hugetlb: remove redundant reservation check condition in alloc_huge_page()

vma_resv_map(vma) checks if a reserve map is associated with the vma.
The routine vma_needs_reservation() will check vma_resv_map(vma) and
return 1 if no reserv map is present.  map_chg is set to the return
value of vma_needs_reservation().  Therefore, !vma_resv_map(vma) is
redundant in the expression:

	map_chg || avoid_reserve || !vma_resv_map(vma);

Remove the redundant check.

[Thanks Mike Kravetz for reshaping this commit message!]

Link: https://lkml.kernel.org/r/20210301104726.45159-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/hugetlb.c

@@ -2316,7 +2316,7 @@ struct page *alloc_huge_page(struct vm_area_struct *vma,
 
 	/* If this allocation is not consuming a reservation, charge it now.
 	 */
-	deferred_reserve = map_chg || avoid_reserve || !vma_resv_map(vma);
+	deferred_reserve = map_chg || avoid_reserve;
 	if (deferred_reserve) {
 		ret = hugetlb_cgroup_charge_cgroup_rsvd(
 			idx, pages_per_huge_page(h), &h_cg);