The patch titled
Subject: mm/hugetlb: simplify refs in memfd_alloc_folio
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-hugetlb-simplify-refs-in-memfd_alloc_folio.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hugetlb-simplify-refs-in-memfd_alloc_folio.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Steve Sistare <steven.sistare@xxxxxxxxxx>
Subject: mm/hugetlb: simplify refs in memfd_alloc_folio
Date: Wed, 4 Sep 2024 12:41:08 -0700
The folio_try_get in memfd_alloc_folio is not necessary. Delete it, and
delete the matching folio_put in memfd_pin_folios. This also avoids
leaking a ref if the memfd_alloc_folio call to hugetlb_add_to_page_cache
fails, which would otherwise need an additional folio_put. This is a
continuation of the fix
"mm/hugetlb: fix memfd_pin_folios free_huge_pages leak"
Link: https://lkml.kernel.org/r/1725478868-61732-1-git-send-email-steven.sistare@xxxxxxxxxx
Fixes: 89c1905d9c14 ("mm/gup: introduce memfd_pin_folios() for pinning memfd folios")
Signed-off-by: Steve Sistare <steven.sistare@xxxxxxxxxx>
Suggested-by: Vivek Kasireddy <vivek.kasireddy@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/gup.c | 4 +---
mm/memfd.c | 2 +-
2 files changed, 2 insertions(+), 4 deletions(-)
--- a/mm/gup.c~mm-hugetlb-simplify-refs-in-memfd_alloc_folio
+++ a/mm/gup.c
@@ -3618,7 +3618,7 @@ long memfd_pin_folios(struct file *memfd
pgoff_t start_idx, end_idx, next_idx;
struct folio *folio = NULL;
struct folio_batch fbatch;
- struct hstate *h = NULL;
+ struct hstate *h;
long ret = -EINVAL;
if (start < 0 || start > end || !max_folios)
@@ -3662,8 +3662,6 @@ long memfd_pin_folios(struct file *memfd
&fbatch);
if (folio) {
folio_put(folio);
- if (h)
- folio_put(folio);
folio = NULL;
}
--- a/mm/memfd.c~mm-hugetlb-simplify-refs-in-memfd_alloc_folio
+++ a/mm/memfd.c
@@ -89,7 +89,7 @@ struct folio *memfd_alloc_folio(struct f
numa_node_id(),
NULL,
gfp_mask);
- if (folio && folio_try_get(folio)) {
+ if (folio) {
err = hugetlb_add_to_page_cache(folio,
memfd->f_mapping,
idx);
_
Patches currently in -mm which might be from steven.sistare@xxxxxxxxxx are
mm-filemap-fix-filemap_get_folios_contig-thp-panic.patch
mm-hugetlb-fix-memfd_pin_folios-free_huge_pages-leak.patch
mm-hugetlb-fix-memfd_pin_folios-resv_huge_pages-leak.patch
mm-gup-fix-memfd_pin_folios-hugetlb-page-allocation.patch
mm-gup-fix-memfd_pin_folios-alloc-race-panic.patch
mm-hugetlb-simplify-refs-in-memfd_alloc_folio.patch
