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authorMike Kravetz <mike.kravetz@oracle.com>2023-06-22 00:24:03 +0300
committerAndrew Morton <akpm@linux-foundation.org>2023-06-24 02:59:32 +0300
commitfd4aed8d985a3236d0877ff6d0c80ad39d4ce81a (patch)
tree01380ababa937d48b99e002c82cea9c6836bee46 /mm
parent16f8eb3eea9eb2a1568279d64ca4dc977e7aa538 (diff)
downloadlinux-fd4aed8d985a3236d0877ff6d0c80ad39d4ce81a.tar.xz
hugetlb: revert use of page_cache_next_miss()
Ackerley Tng reported an issue with hugetlbfs fallocate as noted in the Closes tag. The issue showed up after the conversion of hugetlb page cache lookup code to use page_cache_next_miss. User visible effects are: - hugetlbfs fallocate incorrectly returns -EEXIST if pages are presnet in the file. - hugetlb pages will not be included in core dumps if they need to be brought in via GUP. - userfaultfd UFFDIO_COPY will not notice pages already present in the cache. It may try to allocate a new page and potentially return ENOMEM as opposed to EEXIST. Revert the use page_cache_next_miss() in hugetlb code. IMPORTANT NOTE FOR STABLE BACKPORTS: This patch will apply cleanly to v6.3. However, due to the change of filemap_get_folio() return values, it will not function correctly. This patch must be modified for stable backports. [dan.carpenter@linaro.org: fix hugetlbfs_pagecache_present()] Link: https://lkml.kernel.org/r/efa86091-6a2c-4064-8f55-9b44e1313015@moroto.mountain Link: https://lkml.kernel.org/r/20230621212403.174710-2-mike.kravetz@oracle.com Fixes: d0ce0e47b323 ("mm/hugetlb: convert hugetlb fault paths to use alloc_hugetlb_folio()") Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Reported-by: Ackerley Tng <ackerleytng@google.com> Closes: https://lore.kernel.org/linux-mm/cover.1683069252.git.ackerleytng@google.com Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Erdem Aktas <erdemaktas@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Vishal Annapurve <vannapurve@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/hugetlb.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index d76574425da3..bce28cca73a1 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5728,13 +5728,13 @@ static bool hugetlbfs_pagecache_present(struct hstate *h,
{
struct address_space *mapping = vma->vm_file->f_mapping;
pgoff_t idx = vma_hugecache_offset(h, vma, address);
- bool present;
-
- rcu_read_lock();
- present = page_cache_next_miss(mapping, idx, 1) != idx;
- rcu_read_unlock();
+ struct folio *folio;
- return present;
+ folio = filemap_get_folio(mapping, idx);
+ if (IS_ERR(folio))
+ return false;
+ folio_put(folio);
+ return true;
}
int hugetlb_add_to_page_cache(struct folio *folio, struct address_space *mapping,