Target/iser: Fix iscsit_accept_np and rdma_cm racy flow
authorSagi Grimberg <sagig@mellanox.com>
Tue, 29 Apr 2014 10:13:45 +0000 (13:13 +0300)
committerNicholas Bellinger <nab@linux-iscsi.org>
Fri, 16 May 2014 00:09:10 +0000 (17:09 -0700)
commit531b7bf4bd795d9a09eac92504322a472c010bc8
tree2dfdac4bae9215493c6c293d9e638a6436bfb526
parent9fe63c88b1d59f1ce054d6948ccd3096496ecedb
Target/iser: Fix iscsit_accept_np and rdma_cm racy flow

RDMA CM and iSCSI target flows are asynchronous and completely
uncorrelated. Relying on the fact that iscsi_accept_np will be called
after CM connection request event and will wait for it is a mistake.

When attempting to login to a few targets this flow is racy and
unpredictable, but for parallel login to dozens of targets will
race and hang every time.

The correct synchronizing mechanism in this case is pending on
a semaphore rather than a wait_for_event. We keep the pending
interruptible for iscsi_np cleanup stage.

(Squash patch to remove dead code into parent - nab)

Reported-by: Slava Shwartsman <valyushash@gmail.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
drivers/infiniband/ulp/isert/ib_isert.c
drivers/infiniband/ulp/isert/ib_isert.h