kernel/kernfs-handle-poll-correctly-on-direct_read-files.patch

39 lines
1.1 KiB
Diff

From: NeilBrown <neilb@suse.de>
Date: Mon, 16 Mar 2015 10:44:52 +1100
Subject: [PATCH] kernfs: handle poll correctly on 'direct_read' files.
Kernfs supports two styles of read: direct_read and seqfile_read.
The latter supports 'poll' correctly thanks to the update of
'->event' in kernfs_seq_show.
The former does not as '->event' is never updated on a read.
So add an appropriate update in kernfs_file_direct_read().
This was noticed because some 'md' sysfs attributes were
recently changed to use direct reads.
Reported-by: Prakash Punnoor <prakash@punnoor.de>
Reported-by: Torsten Kaiser <just.for.lkml@googlemail.com>
Fixes: 750f199ee8b578062341e6ddfe36c59ac8ff2dcb
Signed-off-by: NeilBrown <neilb@suse.de>
---
fs/kernfs/file.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index b684e8a132e6..2bacb9988566 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -207,6 +207,7 @@ static ssize_t kernfs_file_direct_read(struct kernfs_open_file *of,
goto out_free;
}
+ of->event = atomic_read(&of->kn->attr.open->event);
ops = kernfs_ops(of->kn);
if (ops->read)
len = ops->read(of, buf, len, *ppos);
--
2.1.0