[PATCH 04/12] IB/srp: Fix connection state tracking

[Bart Van Assche <bart.vanassche@sandisk.com>]

Reception of a DREQ message only causes the state of a single
channel to change. Modify the SRP initiator such that channel
and target connection state are tracked separately. This patch
avoids that following false positive warning can be reported
by srp_destroy_qp():

WARNING: at drivers/infiniband/ulp/srp/ib_srp.c:617 srp_destroy_qp+0xa6/0x120 [ib_srp]()
Call Trace:
[<ffffffff8106e10f>] warn_slowpath_common+0x7f/0xc0
[<ffffffff8106e16a>] warn_slowpath_null+0x1a/0x20
[<ffffffffa0440226>] srp_destroy_qp+0xa6/0x120 [ib_srp]
[<ffffffffa0440322>] srp_free_ch_ib+0x82/0x1e0 [ib_srp]
[<ffffffffa044408b>] srp_create_target+0x7ab/0x998 [ib_srp]
[<ffffffff81346f60>] dev_attr_store+0x20/0x30
[<ffffffff811dd90f>] sysfs_write_file+0xef/0x170
[<ffffffff8116d248>] vfs_write+0xc8/0x190
[<ffffffff8116d411>] sys_write+0x51/0x90

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Sebastian Parschauer <sebastian.riemer@profitbricks.com>
Cc: <stable@vger.kernel.org> #v3.19
---
 drivers/infiniband/ulp/srp/ib_srp.c | 7 ++++---
 drivers/infiniband/ulp/srp/ib_srp.h | 1 +
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 5ce6cfd..0eb07d3 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -465,14 +465,13 @@ static struct srp_fr_pool *srp_alloc_fr_pool(struct srp_target_port *target)
  */
 static void srp_destroy_qp(struct srp_rdma_ch *ch)
 {
-	struct srp_target_port *target = ch->target;
 	static struct ib_qp_attr attr = { .qp_state = IB_QPS_ERR };
 	static struct ib_recv_wr wr = { .wr_id = SRP_LAST_WR_ID };
 	struct ib_recv_wr *bad_wr;
 	int ret;
 
 	/* Destroying a QP and reusing ch->done is only safe if not connected */
-	WARN_ON_ONCE(target->connected);
+	WARN_ON_ONCE(ch->connected);
 
 	ret = ib_modify_qp(ch->qp, &attr, IB_QP_STATE);
 	WARN_ONCE(ret, "ib_cm_init_qp_attr() returned %d\n", ret);
@@ -836,6 +835,7 @@ static void srp_disconnect_target(struct srp_target_port *target)
 
 		for (i = 0; i < target->ch_count; i++) {
 			ch = &target->ch[i];
+			ch->connected = false;
 			if (ch->cm_id && ib_send_cm_dreq(ch->cm_id, NULL, 0)) {
 				shost_printk(KERN_DEBUG, target->scsi_host,
 					     PFX "Sending CM DREQ failed\n");
@@ -1017,6 +1017,7 @@ static int srp_connect_ch(struct srp_rdma_ch *ch, bool multich)
 		switch (ch->status) {
 		case 0:
 			srp_change_conn_state(target, true);
+			ch->connected = true;
 			return 0;
 
 		case SRP_PORT_REDIRECT:
@@ -2367,7 +2368,7 @@ static int srp_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
 	case IB_CM_DREQ_RECEIVED:
 		shost_printk(KERN_WARNING, target->scsi_host,
 			     PFX "DREQ received - connection closed\n");
-		srp_change_conn_state(target, false);
+		ch->connected = false;
 		if (ib_send_cm_drep(cm_id, NULL, 0))
 			shost_printk(KERN_ERR, target->scsi_host,
 				     PFX "Sending CM DREP failed\n");
diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h
index a611556..95a4471 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.h
+++ b/drivers/infiniband/ulp/srp/ib_srp.h
@@ -170,6 +170,7 @@ struct srp_rdma_ch {
 
 	struct completion	tsk_mgmt_done;
 	u8			tsk_mgmt_status;
+	bool			connected;
 };
 
 /**
-- 
2.1.4