libiscsi: Fix iscsi_check_transport_timeouts possible infinite loop

Connection last_ping is not being updated when iscsi_send_nopout fails.
Not updating the last_ping will cause firing a timer to a past time
(last_ping + ping_tmo < current_time) which triggers an infinite loop of
iscsi_check_transport_timeouts() and hogs the cpu.

Fix this issue by checking the return value of iscsi_send_nopout.
If it fails set the next_timeout to one second later.

Signed-off-by: Ariel Nahum <arieln@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Odin.com>

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 33c74d3436c947a7f11ca22498206f6efa97fcc2..6bffd91b973a475d614500a077be0034dbf6786f 100644 (file)
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -976,13 +976,13 @@ static void iscsi_tmf_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
        wake_up(&conn->ehwait);
 }
 
-static void iscsi_send_nopout(struct iscsi_conn *conn, struct iscsi_nopin *rhdr)
+static int iscsi_send_nopout(struct iscsi_conn *conn, struct iscsi_nopin *rhdr)
 {
         struct iscsi_nopout hdr;
        struct iscsi_task *task;
 
        if (!rhdr && conn->ping_task)
-               return;
+               return -EINVAL;
 
        memset(&hdr, 0, sizeof(struct iscsi_nopout));
        hdr.opcode = ISCSI_OP_NOOP_OUT | ISCSI_OP_IMMEDIATE;
@@ -996,13 +996,16 @@ static void iscsi_send_nopout(struct iscsi_conn *conn, struct iscsi_nopin *rhdr)
                hdr.ttt = RESERVED_ITT;
 
        task = __iscsi_conn_send_pdu(conn, (struct iscsi_hdr *)&hdr, NULL, 0);
-       if (!task)
+       if (!task) {
                iscsi_conn_printk(KERN_ERR, conn, "Could not send nopout\n");
-       else if (!rhdr) {
+               return -EIO;
+       } else if (!rhdr) {
                /* only track our nops */
                conn->ping_task = task;
                conn->last_ping = jiffies;
        }
+
+       return 0;
 }
 
 static int iscsi_nop_out_rsp(struct iscsi_task *task,
@@ -2092,8 +2095,10 @@ static void iscsi_check_transport_timeouts(unsigned long data)
        if (time_before_eq(last_recv + recv_timeout, jiffies)) {
                /* send a ping to try to provoke some traffic */
                ISCSI_DBG_CONN(conn, "Sending nopout as ping\n");
-               iscsi_send_nopout(conn, NULL);
-               next_timeout = conn->last_ping + (conn->ping_timeout * HZ);
+               if (iscsi_send_nopout(conn, NULL))
+                       next_timeout = jiffies + (1 * HZ);
+               else
+                       next_timeout = conn->last_ping + (conn->ping_timeout * HZ);
        } else
                next_timeout = last_recv + recv_timeout;