From: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Align the index to the mapping_min_order number of pages in
filemap_get_pages().
Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
---
generic/451 triggers a crash in this path for bs = 16k.
mm/filemap.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index e4d46f79e95d..8a4bbddcf575 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2558,14 +2558,17 @@ static int filemap_get_pages(struct kiocb *iocb, size_t count,
{
struct file *filp = iocb->ki_filp;
struct address_space *mapping = filp->f_mapping;
+ unsigned int min_order = mapping_min_folio_order(mapping);
+ unsigned int nrpages = 1UL << min_order;
struct file_ra_state *ra = &filp->f_ra;
- pgoff_t index = iocb->ki_pos >> PAGE_SHIFT;
+ pgoff_t index = round_down(iocb->ki_pos >> PAGE_SHIFT, nrpages);
pgoff_t last_index;
struct folio *folio;
int err = 0;
/* "last_index" is the index of the page beyond the end of the read */
last_index = DIV_ROUND_UP(iocb->ki_pos + count, PAGE_SIZE);
+ last_index = round_up(last_index, nrpages);
retry:
if (fatal_signal_pending(current))
return -EINTR;
@@ -2581,8 +2584,7 @@ static int filemap_get_pages(struct kiocb *iocb, size_t count,
if (!folio_batch_count(fbatch)) {
if (iocb->ki_flags & (IOCB_NOWAIT | IOCB_WAITQ))
return -EAGAIN;
- err = filemap_create_folio(filp, mapping,
- iocb->ki_pos >> PAGE_SHIFT, fbatch);
+ err = filemap_create_folio(filp, mapping, index, fbatch);
if (err == AOP_TRUNCATED_PAGE)
goto retry;
return err;
--
2.40.1
