fcoe: convert to kworker

The driver creates its own per-CPU threads which are updated based on
CPU hotplug events. It is also possible to use kworkers and remove some
of the kthread infrastrucure.

The code checked ->thread to decide if there is an active per-CPU
thread. By using the kworker infrastructure this is no longer
possible (or required). The thread pointer is saved in `kthread' instead
of `thread' so anything trying to use thread is caught by the
compiler. Currently only the bnx2fc driver is using struct fcoe_percpu_s
and the kthread member.

After a CPU went offline, we may still enqueue items on the "offline"
CPU. This isn't much of a problem. The work will be done on a random
CPU. The allocated crc_eof_page page won't be cleaned up. It is probably
expected that the CPU comes up at some point so it should not be a
problem. The crc_eof_page memory is released of course once the module
is removed.

This patch was only compile-tested due to -ENODEV.

Cc: Vasu Dev <vasu.dev@intel.com>
Cc: "James E.J. Bottomley" <jejb@linux.vnet.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: fcoe-devel@open-fcoe.org
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
index a1881993982c..d6800afd0232 100644
--- a/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
+++ b/drivers/scsi/bnx2fc/bnx2fc_fcoe.c
@@ -486,7 +486,7 @@ static int bnx2fc_rcv(struct sk_buff *skb, struct net_device *dev,
 
         __skb_queue_tail(&bg->fcoe_rx_list, skb);
         if (bg->fcoe_rx_list.qlen == 1)
-                wake_up_process(bg->thread);
+                wake_up_process(bg->kthread);
 
         spin_unlock(&bg->fcoe_rx_list.lock);
 
@@ -2715,7 +2715,7 @@ static int __init bnx2fc_mod_init(void)
         }
         wake_up_process(l2_thread);
         spin_lock_bh(&bg->fcoe_rx_list.lock);
-        bg->thread = l2_thread;
+        bg->kthread = l2_thread;
         spin_unlock_bh(&bg->fcoe_rx_list.lock);
 
         for_each_possible_cpu(cpu) {
@@ -2788,8 +2788,8 @@ static void __exit bnx2fc_mod_exit(void)
         /* Destroy global thread */
         bg = &bnx2fc_global;
         spin_lock_bh(&bg->fcoe_rx_list.lock);
-        l2_thread = bg->thread;
-        bg->thread = NULL;
+        l2_thread = bg->kthread;
+        bg->kthread = NULL;
         while ((skb = __skb_dequeue(&bg->fcoe_rx_list)) != NULL)
                 kfree_skb(skb);