From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
This patch converts qla_tgt_wait_for_cmds() to hold qla_hw_data->hardware_lock
for qla_tgt_cmd state checks related to shutdown logic. This also includes
setting ->cmd_free_comp_set for all cases to signal shutdown in tcm_qla2xxx
code, and the removal of se_cmd->transport_wait_for_tasks() that forces all
outstanding descriptors to complete before tcm_qla2xxx code wakes up
->cmd_free_comp.
This patch also adds a secondary check in qla_tgt_handle_cmd_for_atio()
for qla_tgt->tgt_stop to prevent incoming I/O during full shutdown before
all qla_tgt_sess instances may have their ->tearing_down set, and adds
qla_tgt_cmd->cmd_stop_free_comp used by tcm_qla2xxx code to handle a
seperate completion race.
Reported-by: Roland Dreier <roland@xxxxxxxxxxxxxxx>
Cc: Roland Dreier <roland@xxxxxxxxxxxxxxx>
Cc: Madhuranath Iyengar <mni@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/scsi/qla2xxx/qla_target.c | 52 +++++++++++++++---------------------
drivers/scsi/qla2xxx/qla_target.h | 1 +
2 files changed, 23 insertions(+), 30 deletions(-)
diff --git a/drivers/scsi/qla2xxx/qla_target.c b/drivers/scsi/qla2xxx/qla_target.c
index 757e971..66eedd6 100644
--- a/drivers/scsi/qla2xxx/qla_target.c
+++ b/drivers/scsi/qla2xxx/qla_target.c
@@ -369,13 +369,15 @@ void qla_tgt_response_pkt_all_vps(struct scsi_qla_host *vha, response_t *pkt)
}
-static void qla_tgt_wait_for_cmds(struct qla_tgt_sess *sess)
+/*
+ * Called with qla_hw_data->hardware_lock held.
+ */
+static void qla_tgt_wait_for_cmds(struct qla_tgt_sess *sess, struct qla_hw_data *ha)
{
LIST_HEAD(tmp_list);
struct qla_tgt_cmd *cmd;
struct se_cmd *se_cmd;
unsigned long flags;
- int cmd_free;
spin_lock_irqsave(&sess->sess_cmd_lock, flags);
list_splice_init(&sess->sess_cmd_list, &tmp_list);
@@ -386,38 +388,27 @@ static void qla_tgt_wait_for_cmds(struct qla_tgt_sess *sess)
cmd = list_entry(tmp_list.next, struct qla_tgt_cmd, cmd_list);
DEBUG22(qla_printk(KERN_INFO, sess->vha->hw, "Waiting for cmd:"
" %p\n", cmd));
+ /*
+ * This will signal that completion should be called from
+ * tcm_qla2xxx_release_cmd() context.
+ */
+ atomic_set(&cmd->cmd_free_comp_set, 1);
+ spin_unlock_irq(&ha->hardware_lock);
- if ((atomic_read(&cmd->cmd_free) != 0) ||
- (atomic_read(&cmd->cmd_stop_free) != 0))
- cmd_free = 1;
- else {
- cmd_free = 0;
- atomic_set(&cmd->cmd_free_comp_set, 1);
- smp_mb__after_atomic_dec();
- }
list_del(&cmd->cmd_list);
- DEBUG22(qla_printk(KERN_INFO, sess->vha->hw, "Waiting for cmd: %p,"
- " cmd_free: %d\n", cmd, cmd_free));
-
se_cmd = &cmd->se_cmd;
-
- if (!cmd_free) {
- if (se_cmd->transport_wait_for_tasks) {
- DEBUG22(qla_printk(KERN_INFO, sess->vha->hw, "Before"
- " se_cmd->transport_wait_for_tasks cmd:"
- " %p, se_cmd: %p\n", cmd, se_cmd));
- se_cmd->transport_wait_for_tasks(se_cmd, 0, 0);
-
- DEBUG22(qla_printk(KERN_INFO, sess->vha->hw, "After"
- " se_cmd->transport_wait_for_tasks ----------->\n"));
- }
- }
-
+ /*
+ * Wait for completion of the outstanding descriptor in
+ * tcm_qla2xxx_release_cmd() from transport processing
+ * context, then a direct call to qla_tgt_free_cmd() below.
+ */
DEBUG22(qla_printk(KERN_INFO, sess->vha->hw, "Before"
" wait_for_completion(&cmd->cmd_free_comp); cmd: %p,"
" se_cmd: %p\n", cmd, se_cmd));
+
wait_for_completion(&cmd->cmd_free_comp);
+
DEBUG22(qla_printk(KERN_INFO, sess->vha->hw, "After"
" wait_for_completion(&cmd->cmd_free_comp); cmd: %p,"
" se_cmd: %p\n", cmd, se_cmd));
@@ -429,6 +420,8 @@ static void qla_tgt_wait_for_cmds(struct qla_tgt_sess *sess)
DEBUG22(qla_printk(KERN_INFO, sess->vha->hw, "After"
" qla_tgt_free_cmd --------------------->\n"));
+
+ spin_lock_irq(&ha->hardware_lock);
}
}
@@ -444,9 +437,7 @@ static void qla_tgt_free_session_done(struct qla_tgt_sess *sess)
tgt = sess->tgt;
sess->tearing_down = 1;
- spin_unlock_irq(&ha->hardware_lock);
- qla_tgt_wait_for_cmds(sess);
- spin_lock_irq(&ha->hardware_lock);
+ qla_tgt_wait_for_cmds(sess, ha);
/*
* Release the target session for FC Nexus from fabric module code.
@@ -3294,6 +3285,7 @@ static int qla_tgt_handle_cmd_for_atio(struct scsi_qla_host *vha, atio_t *atio)
INIT_LIST_HEAD(&cmd->cmd_list);
init_completion(&cmd->cmd_free_comp);
+ init_completion(&cmd->cmd_stop_free_comp);
memcpy(&cmd->atio.atio2x, atio, sizeof(*atio));
cmd->state = QLA_TGT_STATE_NEW;
@@ -3324,7 +3316,7 @@ static int qla_tgt_handle_cmd_for_atio(struct scsi_qla_host *vha, atio_t *atio)
}
}
- if (sess->tearing_down)
+ if (sess->tearing_down || tgt->tgt_stop)
goto out_free_cmd;
res = qla_tgt_send_cmd_to_target(vha, cmd, sess);
diff --git a/drivers/scsi/qla2xxx/qla_target.h b/drivers/scsi/qla2xxx/qla_target.h
index 42d5479..0e5cbfd8 100644
--- a/drivers/scsi/qla2xxx/qla_target.h
+++ b/drivers/scsi/qla2xxx/qla_target.h
@@ -902,6 +902,7 @@ struct qla_tgt_cmd {
atomic_t cmd_free;
atomic_t cmd_free_comp_set;
struct completion cmd_free_comp;
+ struct completion cmd_stop_free_comp;
struct se_cmd se_cmd;
/* Sense buffer that will be mapped into outgoing status */
unsigned char sense_buffer[TRANSPORT_SENSE_BUFFER];
--
1.7.2.5
--
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