[patch 07/29] hugetlb: break earlier in add_reservation_in_range() when we can

From: Peter Xu <peterx@redhat.com>
Subject: hugetlb: break earlier in add_reservation_in_range() when we can

All the regions maintained in hugetlb reserved map is inclusive on "from"
but exclusive on "to".  We can break earlier even if rg->from==t because
it already means no possible intersection.

This does not need a Fixes in all cases because when it happens
(rg->from==t) we'll not break out of the loop while we should, however the
next thing we'd do is still add the last file_region we'd need and quit
the loop in the next round.  So this change is not a bugfix (since the old
code should still run okay iiuc), but we'd better still touch it up to
make it logically sane.

Link: https://lkml.kernel.org/r/20210217233547.93892-3-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Kravetz <redacted>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Alexey Dobriyan <redacted>
Cc: Andrea Arcangeli <redacted>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Daniel Vetter <redacted>
Cc: David Airlie <redacted>
Cc: David Gibson <redacted>
Cc: Gal Pressman <redacted>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill Shutemov <redacted>
Cc: Kirill Tkhai <redacted>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <redacted>
Cc: Roland Scheidegger <redacted>
Cc: VMware Graphics <redacted>
Cc: Wei Zhang <redacted>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/hugetlb.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/hugetlb.c~hugetlg-break-earlier-in-add_reservation_in_range-when-we-can
+++ a/mm/hugetlb.c

@@ -387,7 +387,7 @@ static long add_reservation_in_range(str
 		/* When we find a region that starts beyond our range, we've
 		 * finished.
 		 */
-		if (rg->from > t)
+		if (rg->from >= t)
 			break;
 
 		/* Add an entry for last_accounted_offset -> rg->from, and

_