diff options
| author | Jens Axboe <axboe@kernel.dk> | 2020-11-16 13:36:24 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-11-24 13:39:14 +0100 |
| commit | 38d3e20ff427d5b3dc47e3312728bb05dac8b8f4 (patch) | |
| tree | c71ff1af3975333d868b16780ea3e54e85365392 | |
| parent | 3261603426ec2c7e147abad6db95aac5261728d6 (diff) | |
mm: never attempt async page lock if we've transferred data already
commit 0abed7c69b956d135cb6d320c350b2adb213e7d8 upstream.
We catch the case where we enter generic_file_buffered_read() with data
already transferred, but we also need to be careful not to allow an async
page lock if we're looping transferring data. If not, we could be
returning -EIOCBQUEUED instead of the transferred amount, and it could
result in double waitqueue additions as well.
Cc: stable@vger.kernel.org # v5.9
Fixes: 1a0a7853b901 ("mm: support async buffered reads in generic_file_buffered_read()")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | mm/filemap.c | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 407b94d8ce00..6024d15998a4 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2327,10 +2327,15 @@ page_ok: page_not_up_to_date: /* Get exclusive access to the page ... */ - if (iocb->ki_flags & IOCB_WAITQ) + if (iocb->ki_flags & IOCB_WAITQ) { + if (written) { + put_page(page); + goto out; + } error = lock_page_async(page, iocb->ki_waitq); - else + } else { error = lock_page_killable(page); + } if (unlikely(error)) goto readpage_error; @@ -2373,10 +2378,15 @@ readpage: } if (!PageUptodate(page)) { - if (iocb->ki_flags & IOCB_WAITQ) + if (iocb->ki_flags & IOCB_WAITQ) { + if (written) { + put_page(page); + goto out; + } error = lock_page_async(page, iocb->ki_waitq); - else + } else { error = lock_page_killable(page); + } if (unlikely(error)) goto readpage_error; |