[SCSI] bnx2fc: IO completion not processed due to missed wakeup

Driver does not detect a new CQE (completion queue entry) if a thread receives
the wakup when it is in TASK_RUNNING state. Fix is to set the state to
TASK_INTERRUPTIBLE while holding the fp_work_lock.

Also, Use __set_current_task() since it is now set inside a spinlock with
synchronization.

Two other related optimizations:

1.  After we exit the while (!kthread_should_stop()) loop, use
__set_current_state() since synchronization is no longer needed.

2.  Remove set_current_state(TASK_RUNNING) after schedule() since it
should always be TASK_RUNNING after schedule().

Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: Bhanu Prakash Gollapudi <bprakash@broadcom.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

diff --git a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
index 2056890..e2e6475 100644 (file)
--- a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
+++ b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
@@ -437,17 +437,16 @@ static int bnx2fc_l2_rcv_thread(void *arg)
        set_current_state(TASK_INTERRUPTIBLE);
        while (!kthread_should_stop()) {
                schedule();
-               set_current_state(TASK_RUNNING);
                spin_lock_bh(&bg->fcoe_rx_list.lock);
                while ((skb = __skb_dequeue(&bg->fcoe_rx_list)) != NULL) {
                        spin_unlock_bh(&bg->fcoe_rx_list.lock);
                        bnx2fc_recv_frame(skb);
                        spin_lock_bh(&bg->fcoe_rx_list.lock);
                }
+               __set_current_state(TASK_INTERRUPTIBLE);
                spin_unlock_bh(&bg->fcoe_rx_list.lock);
-               set_current_state(TASK_INTERRUPTIBLE);
        }
-       set_current_state(TASK_RUNNING);
+       __set_current_state(TASK_RUNNING);
        return 0;
 }
 
@@ -569,7 +568,6 @@ int bnx2fc_percpu_io_thread(void *arg)
        set_current_state(TASK_INTERRUPTIBLE);
        while (!kthread_should_stop()) {
                schedule();
-               set_current_state(TASK_RUNNING);
                spin_lock_bh(&p->fp_work_lock);
                while (!list_empty(&p->work_list)) {
                        list_splice_init(&p->work_list, &work_list);
@@ -583,10 +581,10 @@ int bnx2fc_percpu_io_thread(void *arg)
 
                        spin_lock_bh(&p->fp_work_lock);
                }
+               __set_current_state(TASK_INTERRUPTIBLE);
                spin_unlock_bh(&p->fp_work_lock);
-               set_current_state(TASK_INTERRUPTIBLE);
        }
-       set_current_state(TASK_RUNNING);
+       __set_current_state(TASK_RUNNING);
 
        return 0;
 }