3.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
commit 03e7848a64ed535a30f5d7fc6dede2d5a6a2534b upstream.
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@xxxxxxxxxxxx>
Cc: Or Gerlitz <ogerlitz@xxxxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/infiniband/ulp/isert/ib_isert.c | 29 +++++++++++++++++++++--------
1 file changed, 21 insertions(+), 8 deletions(-)
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -1201,7 +1201,7 @@ isert_unmap_cmd(struct isert_cmd *isert_
}
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;
@@ -1216,8 +1216,21 @@ isert_put_cmd(struct isert_cmd *isert_cm
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);
+ }
+ }
isert_unmap_cmd(isert_cmd, isert_conn);
transport_generic_free_cmd(&cmd->se_cmd, 0);
@@ -1271,7 +1284,7 @@ isert_unmap_tx_desc(struct iser_tx_desc
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->sense_buf_dma != 0) {
pr_debug("Calling ib_dma_unmap_single for isert_cmd->sense_buf_dma\n");
@@ -1281,7 +1294,7 @@ isert_completion_put(struct iser_tx_desc
}
isert_unmap_tx_desc(tx_desc, ib_dev);
- isert_put_cmd(isert_cmd);
+ isert_put_cmd(isert_cmd, comp_err);
}
static void
@@ -1336,14 +1349,14 @@ isert_do_control_comp(struct work_struct
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");
@@ -1382,7 +1395,7 @@ isert_response_completion(struct iser_tx
atomic_sub(wr->send_wr_num + 1, &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
@@ -1436,7 +1449,7 @@ isert_cq_tx_comp_err(struct iser_tx_desc
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
--
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