On 2/12/20 5:13 AM, Jan Kara wrote:
When handling a page fault, we drop mmap_sem to start async readahead so
that we don't block on IO submission with mmap_sem held. However
there's no point to drop mmap_sem in case readahead is disabled. Handle
that case to avoid pointless dropping of mmap_sem and retrying the
fault. This was actually reported to block mlockall(MCL_CURRENT)
indefinitely.
Fixes: 6b4c9f446981 ("filemap: drop the mmap_sem for all blocking operations")
Reported-by: Minchan Kim <minchan@xxxxxxxxxx>
Reported-by: Robert Stupp <snazy@xxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
Thanks,
Josef
