diff options
| author | Chenghao Duan <duanchenghao@kylinos.cn> | 2026-03-26 16:47:21 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-04-18 00:10:52 -0700 |
| commit | ed2a29dc6dcf4630ef19d588704c2ca7b46607bb (patch) | |
| tree | 36d9e1c76fcd9d1ca8aaa600ce68dfc912285f36 | |
| parent | 7cf6d940f4032d87d9cfe6b27c0e49e309818e5d (diff) | |
mm/memfd: use folio_nr_pages() for shmem inode accounting
I found several modifiable points while reading the code.
This patch (of 6):
Patch series "Modify memfd_luo code", v3.
memfd_luo_retrieve_folios() called shmem_inode_acct_blocks() and
shmem_recalc_inode() with hardcoded 1 instead of the actual folio page
count. memfd may use large folios (THP/hugepages), causing quota/limit
under-accounting and incorrect stat output.
Fix by using folio_nr_pages(folio) for both functions.
Issue found by AI review and suggested by Pratyush Yadav <pratyush@kernel.org>.
https://sashiko.dev/#/patchset/20260319012845.29570-1-duanchenghao%40kylinos.cn
Link: https://lore.kernel.org/20260326084727.118437-1-duanchenghao@kylinos.cn
Link: https://lore.kernel.org/20260326084727.118437-2-duanchenghao@kylinos.cn
Signed-off-by: Chenghao Duan <duanchenghao@kylinos.cn>
Suggested-by: Pratyush Yadav <pratyush@kernel.org>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Cc: Haoran Jiang <jianghaoran@kylinos.cn>
Cc: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/memfd_luo.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/mm/memfd_luo.c b/mm/memfd_luo.c index 9130e6ce396d..ec4c3e1e2891 100644 --- a/mm/memfd_luo.c +++ b/mm/memfd_luo.c @@ -410,6 +410,7 @@ static int memfd_luo_retrieve_folios(struct file *file, struct inode *inode = file_inode(file); struct address_space *mapping = inode->i_mapping; struct folio *folio; + long npages; int err = -EIO; long i; @@ -456,14 +457,15 @@ static int memfd_luo_retrieve_folios(struct file *file, if (flags & MEMFD_LUO_FOLIO_DIRTY) folio_mark_dirty(folio); - err = shmem_inode_acct_blocks(inode, 1); + npages = folio_nr_pages(folio); + err = shmem_inode_acct_blocks(inode, npages); if (err) { - pr_err("shmem: failed to account folio index %ld: %d\n", - i, err); + pr_err("shmem: failed to account folio index %ld(%ld pages): %d\n", + i, npages, err); goto unlock_folio; } - shmem_recalc_inode(inode, 1, 0); + shmem_recalc_inode(inode, npages, 0); folio_add_lru(folio); folio_unlock(folio); folio_put(folio); |