From: Md Haris Iqbal haris.iqbal@cloud.ionos.com
[ Upstream commit 41db63a7efe1c8c2dd282c1849a6ebfbbedbaf67 ]
When get_next_path_min_inflight is called to select the next path, it iterates over the list of available rtrs_clt_sess (paths). It then reads the number of inflight IOs for that path to select one which has the least inflight IO.
But it may so happen that rtrs_clt_sess (path) is no longer in the connected state because closing or error recovery paths can change the status of the rtrs_clt_Sess.
For example, the client sent the heart-beat and did not get the response, it would change the session status and stop IO processing. The added checking of this patch can prevent accessing the broken path and generating duplicated error messages.
It is ok if the status is changed after checking the status because the error recovery path does not free memory and only tries to reconnection. And also it is ok if the session is closed after checking the status because closing the session changes the session status and flush all IO beforing free memory. If the session is being accessed for IO processing, the closing session will wait.
Fixes: 6a98d71daea18 ("RDMA/rtrs: client: main functionality") Link: https://lore.kernel.org/r/20210528113018.52290-13-jinpu.wang@ionos.com Signed-off-by: Md Haris Iqbal haris.iqbal@ionos.com Reviewed-by: Gioh Kim gi-oh.kim@ionos.com Signed-off-by: Gioh Kim gi-oh.kim@ionos.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/infiniband/ulp/rtrs/rtrs-clt.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c index 0a794d748a7a..a563c9b9d52c 100644 --- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c +++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c @@ -814,6 +814,9 @@ static struct rtrs_clt_sess *get_next_path_min_inflight(struct path_it *it) int inflight;
list_for_each_entry_rcu(sess, &clt->paths_list, s.entry) { + if (unlikely(READ_ONCE(sess->state) != RTRS_CLT_CONNECTED)) + continue; + if (unlikely(!list_empty(raw_cpu_ptr(sess->mp_skip_entry)))) continue;