diff options
| author | Christoph Hellwig <hch@lst.de> | 2023-03-07 15:34:08 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-04-05 19:42:42 -0700 |
| commit | aaeb94eb86c58a89e70ae2dda46e137a72508ae3 (patch) | |
| tree | ab0a5ff340636ffcba17677f74176430d73eb09d /mm | |
| parent | 81914aff84e83561ab556dab380e7bbe9c2102b1 (diff) | |
shmem: open code the page cache lookup in shmem_get_folio_gfp
Use the very low level filemap_get_entry helper to look up the entry in
the xarray, and then:
- don't bother locking the folio if only doing a userfault notification
- open code locking the page and checking for truncation in a related
code block
This will allow to eventually remove the FGP_ENTRY flag.
[hughd@google.com: adjust the new comment line]
Link: https://lkml.kernel.org/r/af178ebb-1076-a38c-1dc1-2a37ccce4a3@google.com
Link: https://lkml.kernel.org/r/20230307143410.28031-6-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/shmem.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/mm/shmem.c b/mm/shmem.c index 1549866c208f..93cb39852a16 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1880,12 +1880,10 @@ repeat: sbinfo = SHMEM_SB(inode->i_sb); charge_mm = vma ? vma->vm_mm : NULL; - folio = __filemap_get_folio(mapping, index, FGP_ENTRY | FGP_LOCK, 0); + folio = filemap_get_entry(mapping, index); if (folio && vma && userfaultfd_minor(vma)) { - if (!xa_is_value(folio)) { - folio_unlock(folio); + if (!xa_is_value(folio)) folio_put(folio); - } *fault_type = handle_userfault(vmf, VM_UFFD_MINOR); return 0; } @@ -1901,6 +1899,14 @@ repeat: } if (folio) { + folio_lock(folio); + + /* Has the folio been truncated or swapped out? */ + if (unlikely(folio->mapping != mapping)) { + folio_unlock(folio); + folio_put(folio); + goto repeat; + } if (sgp == SGP_WRITE) folio_mark_accessed(folio); if (folio_test_uptodate(folio)) |