From: Lee Duncan <ldun...@suse.com>
iSCSI NOPs are sometimes "lost", mistakenly sent to the
user-land iscsid daemon instead of handled in the kernel,
as they should be, resulting in a message from the daemon like:
> iscsid: Got nop in, but kernel supports nop handling.
This can occur because of the new forward- and back-locks,
and the fact that an iSCSI NOP response can occur before
processing of the NOP send is complete. This can result
in "conn->ping_task" being NULL in iscsi_nop_out_rsp(),
when the pointer is actually in the process of being set.
To work around this, we add a new state to the "ping_task"
pointer. In addition to NULL (not assigned) and a pointer
(assigned), we add the state "being set", which is signaled
with an INVALID pointer (using "-1").
Signed-off-by: Lee Duncan <ldun...@suse.com>
---
drivers/scsi/libiscsi.c | 11 ++++++++++-
include/scsi/libiscsi.h | 3 +++
2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 1e9c3171fa9f..5eb064787ee2 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -738,6 +738,9 @@ __iscsi_conn_send_pdu(struct iscsi_conn *conn, struct
iscsi_hdr *hdr,
task->conn->session->age);
}
+ if (unlikely(READ_ONCE(conn->ping_task) == INVALID_SCSI_TASK))
+ WRITE_ONCE(conn->ping_task, task);
+
if (!ihost->workq) {
if (iscsi_prep_mgmt_task(conn, task))
goto free_task;
@@ -941,6 +944,11 @@ static int iscsi_send_nopout(struct iscsi_conn *conn,
struct iscsi_nopin *rhdr)
struct iscsi_nopout hdr;
struct iscsi_task *task;
+ if (!rhdr) {
+ if (READ_ONCE(conn->ping_task))
+ return -EINVAL;
+ WRITE_ONCE(conn->ping_task, INVALID_SCSI_TASK);
+ }
if (!rhdr && conn->ping_task)
return -EINVAL;
@@ -957,11 +965,12 @@ static int iscsi_send_nopout(struct iscsi_conn *conn,
struct iscsi_nopin *rhdr)
task = __iscsi_conn_send_pdu(conn, (struct iscsi_hdr *)&hdr, NULL, 0);
if (!task) {
+ if (!rhdr)
+ WRITE_ONCE(conn->ping_task, NULL);
iscsi_conn_printk(KERN_ERR, conn, "Could not send nopout\n");
return -EIO;
} else if (!rhdr) {
/* only track our nops */
- conn->ping_task = task;
conn->last_ping = jiffies;
}
diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
index c25fb86ffae9..b3bbd10eb3f0 100644
--- a/include/scsi/libiscsi.h
+++ b/include/scsi/libiscsi.h
@@ -132,6 +132,9 @@ struct iscsi_task {
void *dd_data; /* driver/transport data */
};
+/* invalid scsi_task pointer */
+#define INVALID_SCSI_TASK (struct iscsi_task *)-1l
+
static inline int iscsi_task_has_unsol_data(struct iscsi_task *task)
{
return task->unsol_r2t.data_length > task->unsol_r2t.sent;
--
2.26.2
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