diff mbox series

[112/143] mm/gup: return an error on migration failure

Message ID 20210505013846.4yrwf55ju%akpm@linux-foundation.org (mailing list archive)
State New, archived
Headers show
Series [001/143] mm: introduce and use mapping_empty() | expand

Commit Message

Andrew Morton May 5, 2021, 1:38 a.m. UTC 
From: Pavel Tatashin <pasha.tatashin@soleen.com>
Subject: mm/gup: return an error on migration failure

When migration failure occurs, we still pin pages, which means
that we may pin CMA movable pages which should never be the case.

Instead return an error without pinning pages when migration failure
happens.

No need to retry migrating, because migrate_pages() already retries
10 times.

Link: https://lkml.kernel.org/r/20210215161349.246722-4-pasha.tatashin@soleen.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Tyler Hicks <tyhicks@linux.microsoft.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/gup.c |   17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)
diff mbox series

Patch

--- a/mm/gup.c~mm-gup-return-an-error-on-migration-failure
+++ a/mm/gup.c
@@ -1610,7 +1610,6 @@  static long check_and_migrate_cma_pages(
 {
 	unsigned long i;
 	bool drain_allow = true;
-	bool migrate_allow = true;
 	LIST_HEAD(cma_page_list);
 	long ret = nr_pages;
 	struct page *prev_head, *head;
@@ -1661,17 +1660,15 @@  check_again:
 			for (i = 0; i < nr_pages; i++)
 				put_page(pages[i]);
 
-		if (migrate_pages(&cma_page_list, alloc_migration_target, NULL,
-			(unsigned long)&mtc, MIGRATE_SYNC, MR_CONTIG_RANGE)) {
-			/*
-			 * some of the pages failed migration. Do get_user_pages
-			 * without migration.
-			 */
-			migrate_allow = false;
-
+		ret = migrate_pages(&cma_page_list, alloc_migration_target,
+				    NULL, (unsigned long)&mtc, MIGRATE_SYNC,
+				    MR_CONTIG_RANGE);
+		if (ret) {
 			if (!list_empty(&cma_page_list))
 				putback_movable_pages(&cma_page_list);
+			return ret > 0 ? -ENOMEM : ret;
 		}
+
 		/*
 		 * We did migrate all the pages, Try to get the page references
 		 * again migrating any new CMA pages which we failed to isolate
@@ -1681,7 +1678,7 @@  check_again:
 						   pages, vmas, NULL,
 						   gup_flags);
 
-		if ((ret > 0) && migrate_allow) {
+		if (ret > 0) {
 			nr_pages = ret;
 			drain_allow = true;
 			goto check_again;