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iser-target: Add missing se_cmd put for WRITE_PENDING in tx_comp_err
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This patch fixes a bug where outstanding RDMA_READs with WRITE_PENDING
status require an extra target_put_sess_cmd() in isert_put_cmd() code
when called from isert_cq_tx_comp_err() + isert_cq_drain_comp_llist()
context during session shutdown.

The extra kref PUT is required so that transport_generic_free_cmd()
invokes the last target_put_sess_cmd() -> target_release_cmd_kref(),
which will complete(&se_cmd->cmd_wait_comp) the outstanding se_cmd
descriptor with WRITE_PENDING status, and awake the completion in
target_wait_for_sess_cmds() to invoke TFO->release_cmd().

The bug was manifesting itself in target_wait_for_sess_cmds() where
a se_cmd descriptor with WRITE_PENDING status would end up sleeping
indefinately.

Acked-by: Sagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: <stable@vger.kernel.org> #3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
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Nicholas Bellinger committed Apr 7, 2014
1 parent 131e6ab commit 03e7848
Showing 1 changed file with 26 additions and 11 deletions.
37 changes: 26 additions & 11 deletions drivers/infiniband/ulp/isert/ib_isert.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1580,7 +1580,7 @@ isert_unreg_rdma(struct isert_cmd *isert_cmd, struct isert_conn *isert_conn)
}

static void
isert_put_cmd(struct isert_cmd *isert_cmd)
isert_put_cmd(struct isert_cmd *isert_cmd, bool comp_err)
{
struct iscsi_cmd *cmd = isert_cmd->iscsi_cmd;
struct isert_conn *isert_conn = isert_cmd->conn;
Expand All @@ -1596,8 +1596,21 @@ isert_put_cmd(struct isert_cmd *isert_cmd)
list_del_init(&cmd->i_conn_node);
spin_unlock_bh(&conn->cmd_lock);

if (cmd->data_direction == DMA_TO_DEVICE)
if (cmd->data_direction == DMA_TO_DEVICE) {
iscsit_stop_dataout_timer(cmd);
/*
* Check for special case during comp_err where
* WRITE_PENDING has been handed off from core,
* but requires an extra target_put_sess_cmd()
* before transport_generic_free_cmd() below.
*/
if (comp_err &&
cmd->se_cmd.t_state == TRANSPORT_WRITE_PENDING) {
struct se_cmd *se_cmd = &cmd->se_cmd;

target_put_sess_cmd(se_cmd->se_sess, se_cmd);
}
}

device->unreg_rdma_mem(isert_cmd, isert_conn);
transport_generic_free_cmd(&cmd->se_cmd, 0);
Expand Down Expand Up @@ -1652,7 +1665,7 @@ isert_unmap_tx_desc(struct iser_tx_desc *tx_desc, struct ib_device *ib_dev)

static void
isert_completion_put(struct iser_tx_desc *tx_desc, struct isert_cmd *isert_cmd,
struct ib_device *ib_dev)
struct ib_device *ib_dev, bool comp_err)
{
if (isert_cmd->pdu_buf_dma != 0) {
pr_debug("Calling ib_dma_unmap_single for isert_cmd->pdu_buf_dma\n");
Expand All @@ -1662,7 +1675,7 @@ isert_completion_put(struct iser_tx_desc *tx_desc, struct isert_cmd *isert_cmd,
}

isert_unmap_tx_desc(tx_desc, ib_dev);
isert_put_cmd(isert_cmd);
isert_put_cmd(isert_cmd, comp_err);
}

static int
Expand Down Expand Up @@ -1787,14 +1800,14 @@ isert_do_control_comp(struct work_struct *work)
iscsit_tmr_post_handler(cmd, cmd->conn);

cmd->i_state = ISTATE_SENT_STATUS;
isert_completion_put(&isert_cmd->tx_desc, isert_cmd, ib_dev);
isert_completion_put(&isert_cmd->tx_desc, isert_cmd, ib_dev, false);
break;
case ISTATE_SEND_REJECT:
pr_debug("Got isert_do_control_comp ISTATE_SEND_REJECT: >>>\n");
atomic_dec(&isert_conn->post_send_buf_count);

cmd->i_state = ISTATE_SENT_STATUS;
isert_completion_put(&isert_cmd->tx_desc, isert_cmd, ib_dev);
isert_completion_put(&isert_cmd->tx_desc, isert_cmd, ib_dev, false);
break;
case ISTATE_SEND_LOGOUTRSP:
pr_debug("Calling iscsit_logout_post_handler >>>>>>>>>>>>>>\n");
Expand All @@ -1808,7 +1821,7 @@ isert_do_control_comp(struct work_struct *work)
case ISTATE_SEND_TEXTRSP:
atomic_dec(&isert_conn->post_send_buf_count);
cmd->i_state = ISTATE_SENT_STATUS;
isert_completion_put(&isert_cmd->tx_desc, isert_cmd, ib_dev);
isert_completion_put(&isert_cmd->tx_desc, isert_cmd, ib_dev, false);
break;
default:
pr_err("Unknown do_control_comp i_state %d\n", cmd->i_state);
Expand Down Expand Up @@ -1850,7 +1863,7 @@ isert_response_completion(struct iser_tx_desc *tx_desc,
atomic_dec(&isert_conn->post_send_buf_count);

cmd->i_state = ISTATE_SENT_STATUS;
isert_completion_put(tx_desc, isert_cmd, ib_dev);
isert_completion_put(tx_desc, isert_cmd, ib_dev, false);
}

static void
Expand Down Expand Up @@ -1943,7 +1956,8 @@ isert_cq_drain_comp_llist(struct isert_conn *isert_conn, struct ib_device *ib_de
&isert_conn->post_send_buf_count);
else
atomic_dec(&isert_conn->post_send_buf_count);
isert_completion_put(t, t->isert_cmd, ib_dev);

isert_completion_put(t, t->isert_cmd, ib_dev, true);
}
}

Expand Down Expand Up @@ -1973,14 +1987,15 @@ isert_cq_tx_comp_err(struct iser_tx_desc *tx_desc, struct isert_conn *isert_conn
&isert_conn->post_send_buf_count);
else
atomic_dec(&isert_conn->post_send_buf_count);
isert_completion_put(t, t->isert_cmd, ib_dev);

isert_completion_put(t, t->isert_cmd, ib_dev, true);
}
tx_desc->comp_llnode_batch = NULL;

if (!isert_cmd)
isert_unmap_tx_desc(tx_desc, ib_dev);
else
isert_completion_put(tx_desc, isert_cmd, ib_dev);
isert_completion_put(tx_desc, isert_cmd, ib_dev, true);
}

static void
Expand Down

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