s390/cio: cio_ignore_proc_seq_next should increase position index

[ Upstream commit 8b101a5e14f2161869636ff9cb4907b7749dc0c2 ]

if seq_file .next fuction does not change position index,
read after some lseek can generate unexpected output.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=206283
Link: https://lore.kernel.org/r/d44c53a7-9bc1-15c7-6d4a-0c10cb9dffce@virtuozzo.com
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Vasily Averin 2020-01-24 08:48:55 +03:00 committed by prashantpaddune
parent 2987bd66d7
commit dcc4eb37b6

View File

@ -303,8 +303,10 @@ static void *
cio_ignore_proc_seq_next(struct seq_file *s, void *it, loff_t *offset) cio_ignore_proc_seq_next(struct seq_file *s, void *it, loff_t *offset)
{ {
struct ccwdev_iter *iter; struct ccwdev_iter *iter;
loff_t p = *offset;
if (*offset >= (__MAX_SUBCHANNEL + 1) * (__MAX_SSID + 1)) (*offset)++;
if (p >= (__MAX_SUBCHANNEL + 1) * (__MAX_SSID + 1))
return NULL; return NULL;
iter = it; iter = it;
if (iter->devno == __MAX_SUBCHANNEL) { if (iter->devno == __MAX_SUBCHANNEL) {
@ -314,7 +316,6 @@ cio_ignore_proc_seq_next(struct seq_file *s, void *it, loff_t *offset)
return NULL; return NULL;
} else } else
iter->devno++; iter->devno++;
(*offset)++;
return iter; return iter;
} }