From: Steve Sistare Date: Wed, 4 Sep 2024 19:41:08 +0000 (-0700) Subject: mm/hugetlb: simplify refs in memfd_alloc_folio X-Git-Tag: v6.12-rc1~26^2~11 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=dc677b5f3765cfd0944c8873d1ea57f1a3439676;p=thirdparty%2Fkernel%2Flinux.git mm/hugetlb: simplify refs in memfd_alloc_folio 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. That error path is also broken in a second way -- when its folio_put causes the ref to become 0, it will implicitly call free_huge_folio, but then the path *explicitly* calls free_huge_folio. Delete the latter. This is a continuation of the fix "mm/hugetlb: fix memfd_pin_folios free_huge_pages leak" [steven.sistare@oracle.com: remove explicit call to free_huge_folio(), per Matthew] Link: https://lkml.kernel.org/r/Zti-7nPVMcGgpcbi@casper.infradead.org Link: https://lkml.kernel.org/r/1725481920-82506-1-git-send-email-steven.sistare@oracle.com Link: https://lkml.kernel.org/r/1725478868-61732-1-git-send-email-steven.sistare@oracle.com Fixes: 89c1905d9c14 ("mm/gup: introduce memfd_pin_folios() for pinning memfd folios") Signed-off-by: Steve Sistare Suggested-by: Vivek Kasireddy Cc: David Hildenbrand Cc: Jason Gunthorpe Cc: Matthew Wilcox Cc: Muchun Song Cc: Peter Xu Cc: Signed-off-by: Andrew Morton --- diff --git a/mm/gup.c b/mm/gup.c index 8d9b560a0fec2..a82890b46a365 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -3615,7 +3615,7 @@ long memfd_pin_folios(struct file *memfd, loff_t start, loff_t end, 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) @@ -3659,8 +3659,6 @@ long memfd_pin_folios(struct file *memfd, loff_t start, loff_t end, &fbatch); if (folio) { folio_put(folio); - if (h) - folio_put(folio); folio = NULL; } diff --git a/mm/memfd.c b/mm/memfd.c index bcb131db829d4..c17c3ea701a17 100644 --- a/mm/memfd.c +++ b/mm/memfd.c @@ -89,13 +89,12 @@ struct folio *memfd_alloc_folio(struct file *memfd, pgoff_t idx) 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); if (err) { folio_put(folio); - free_huge_folio(folio); return ERR_PTR(err); } folio_unlock(folio);