iser-target: Fix command leak for tx_desc->comp_llnode_batch

This patch addresses a number of active I/O shutdown issues
related to isert_cmd descriptors being leaked that are part
of a completion interrupt coalescing batch.

This includes adding logic in isert_cq_tx_comp_err() to
drain any associated tx_desc->comp_llnode_batch, as well
as isert_cq_drain_comp_llist() to drain any associated
isert_conn->conn_comp_llist.

Also, set tx_desc->llnode_active in isert_init_send_wr()
in order to determine when work requests need to be skipped
in isert_cq_tx_work() exception path code.

Finally, update isert_init_send_wr() to only allow interrupt
coalescing when ISER_CONN_UP.

Acked-by: Sagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: <stable@vger.kernel.org> #3.13+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

2 files changed, 46 insertions, 6 deletions

diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index 614a6ef6a79d..8ee228e9ab5a 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -497,7 +497,6 @@ isert_connect_request(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
         kref_init(&isert_conn->conn_kref);
         kref_get(&isert_conn->conn_kref);
         mutex_init(&isert_conn->conn_mutex);
-        mutex_init(&isert_conn->conn_comp_mutex);
         spin_lock_init(&isert_conn->conn_lock);
 
         cma_id->context = isert_conn;
@@ -888,16 +887,17 @@ isert_init_send_wr(struct isert_conn *isert_conn, struct isert_cmd *isert_cmd,
          * Coalesce send completion interrupts by only setting IB_SEND_SIGNALED
          * bit for every ISERT_COMP_BATCH_COUNT number of ib_post_send() calls.
          */
-        mutex_lock(&isert_conn->conn_comp_mutex);
-        if (coalesce &&
+        mutex_lock(&isert_conn->conn_mutex);
+        if (coalesce && isert_conn->state == ISER_CONN_UP &&
             ++isert_conn->conn_comp_batch < ISERT_COMP_BATCH_COUNT) {
+                tx_desc->llnode_active = true;
                 llist_add(&tx_desc->comp_llnode, &isert_conn->conn_comp_llist);
-                mutex_unlock(&isert_conn->conn_comp_mutex);
+                mutex_unlock(&isert_conn->conn_mutex);
                 return;
         }
         isert_conn->conn_comp_batch = 0;
         tx_desc->comp_llnode_batch = llist_del_all(&isert_conn->conn_comp_llist);
-        mutex_unlock(&isert_conn->conn_comp_mutex);
+        mutex_unlock(&isert_conn->conn_mutex);
 
         send_wr->send_flags = IB_SEND_SIGNALED;
 }
@@ -1693,10 +1693,45 @@ isert_send_completion(struct iser_tx_desc *tx_desc,
 }
 
 static void
+isert_cq_drain_comp_llist(struct isert_conn *isert_conn, struct ib_device *ib_dev)
+{
+        struct llist_node *llnode;
+        struct isert_rdma_wr *wr;
+        struct iser_tx_desc *t;
+
+        mutex_lock(&isert_conn->conn_mutex);
+        llnode = llist_del_all(&isert_conn->conn_comp_llist);
+        isert_conn->conn_comp_batch = 0;
+        mutex_unlock(&isert_conn->conn_mutex);
+
+        while (llnode) {
+                t = llist_entry(llnode, struct iser_tx_desc, comp_llnode);
+                llnode = llist_next(llnode);
+                wr = &t->isert_cmd->rdma_wr;
+
+                atomic_sub(wr->send_wr_num + 1, &isert_conn->post_send_buf_count);
+                isert_completion_put(t, t->isert_cmd, ib_dev);
+        }
+}
+
+static void
 isert_cq_tx_comp_err(struct iser_tx_desc *tx_desc, struct isert_conn *isert_conn)
 {
         struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
         struct isert_cmd *isert_cmd = tx_desc->isert_cmd;
+        struct llist_node *llnode = tx_desc->comp_llnode_batch;
+        struct isert_rdma_wr *wr;
+        struct iser_tx_desc *t;
+
+        while (llnode) {
+                t = llist_entry(llnode, struct iser_tx_desc, comp_llnode);
+                llnode = llist_next(llnode);
+                wr = &t->isert_cmd->rdma_wr;
+
+                atomic_sub(wr->send_wr_num + 1, &isert_conn->post_send_buf_count);
+                isert_completion_put(t, t->isert_cmd, ib_dev);
+        }
+        tx_desc->comp_llnode_batch = NULL;
 
         if (!isert_cmd)
                 isert_unmap_tx_desc(tx_desc, ib_dev);
@@ -1713,6 +1748,8 @@ isert_cq_rx_comp_err(struct isert_conn *isert_conn)
         if (isert_conn->post_recv_buf_count)
                 return;
 
+        isert_cq_drain_comp_llist(isert_conn, ib_dev);
+
         if (conn->sess) {
                 target_sess_cmd_list_set_waiting(conn->sess->se_sess);
                 target_wait_for_sess_cmds(conn->sess->se_sess);
@@ -1752,6 +1789,9 @@ isert_cq_tx_work(struct work_struct *work)
                         pr_debug("TX wc.vendor_err: 0x%08x\n", wc.vendor_err);
 
                         if (wc.wr_id != ISER_FASTREG_LI_WRID) {
+                                if (tx_desc->llnode_active)
+                                        continue;
+
                                 atomic_dec(&isert_conn->post_send_buf_count);
                                 isert_cq_tx_comp_err(tx_desc, isert_conn);
                         }
diff --git a/drivers/infiniband/ulp/isert/ib_isert.h b/drivers/infiniband/ulp/isert/ib_isert.h
index 10be55a3185e..f6ae7f5dd408 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.h
+++ b/drivers/infiniband/ulp/isert/ib_isert.h
@@ -46,6 +46,7 @@ struct iser_tx_desc {
         struct isert_cmd *isert_cmd;
         struct llist_node *comp_llnode_batch;
         struct llist_node comp_llnode;
+        bool            llnode_active;
         struct ib_send_wr send_wr;
 } __packed;
 
@@ -127,7 +128,6 @@ struct isert_conn {
 #define ISERT_COMP_BATCH_COUNT  8
         int                     conn_comp_batch;
         struct llist_head       conn_comp_llist;
-        struct mutex            conn_comp_mutex;
 };
 
 #define ISERT_MAX_CQ 64