scsi: fnic: Move fnic_fnic_flush_tx() to a work queue

Rather than call 'fnic_flush_tx()' from interrupt context we should be
moving it onto a work queue to avoid any locking issues.

Fixes: 1a19755 ("scsi: fcoe: Fix potential deadlock on &fip->ctlr_lock")
Co-developed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Lee Duncan <lduncan@suse.com>
Link: https://lore.kernel.org/r/ce5ffa5d0ff82c2b2e283b3b4bff23291d49b05c.1707500786.git.lduncan@suse.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/fnic/fnic.h

@@ -305,6 +305,7 @@ struct fnic {
 	unsigned int copy_wq_base;
 	struct work_struct link_work;
 	struct work_struct frame_work;
+	struct work_struct flush_work;
 	struct sk_buff_head frame_queue;
 	struct sk_buff_head tx_queue;
 
@@ -363,7 +364,7 @@ void fnic_handle_event(struct work_struct *work);
 int fnic_rq_cmpl_handler(struct fnic *fnic, int);
 int fnic_alloc_rq_frame(struct vnic_rq *rq);
 void fnic_free_rq_buf(struct vnic_rq *rq, struct vnic_rq_buf *buf);
-void fnic_flush_tx(struct fnic *);
+void fnic_flush_tx(struct work_struct *work);
 void fnic_eth_send(struct fcoe_ctlr *, struct sk_buff *skb);
 void fnic_set_port_id(struct fc_lport *, u32, struct fc_frame *);
 void fnic_update_mac(struct fc_lport *, u8 *new);

drivers/scsi/fnic/fnic_fcs.c

@@ -1182,16 +1182,17 @@ int fnic_send(struct fc_lport *lp, struct fc_frame *fp)
 
 /**
  * fnic_flush_tx() - send queued frames.
- * @fnic: fnic device
+ * @work: pointer to work element
  *
  * Send frames that were waiting to go out in FC or Ethernet mode.
  * Whenever changing modes we purge queued frames, so these frames should
  * be queued for the stable mode that we're in, either FC or Ethernet.
  *
  * Called without fnic_lock held.
  */
-void fnic_flush_tx(struct fnic *fnic)
+void fnic_flush_tx(struct work_struct *work)
 {
+	struct fnic *fnic = container_of(work, struct fnic, flush_work);
 	struct sk_buff *skb;
 	struct fc_frame *fp;
 

drivers/scsi/fnic/fnic_main.c

@@ -830,6 +830,7 @@ static int fnic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		spin_lock_init(&fnic->vlans_lock);
 		INIT_WORK(&fnic->fip_frame_work, fnic_handle_fip_frame);
 		INIT_WORK(&fnic->event_work, fnic_handle_event);
+		INIT_WORK(&fnic->flush_work, fnic_flush_tx);
 		skb_queue_head_init(&fnic->fip_frame_queue);
 		INIT_LIST_HEAD(&fnic->evlist);
 		INIT_LIST_HEAD(&fnic->vlans);

drivers/scsi/fnic/fnic_scsi.c

@@ -680,7 +680,7 @@ static int fnic_fcpio_fw_reset_cmpl_handler(struct fnic *fnic,
 
 	spin_unlock_irqrestore(&fnic->fnic_lock, flags);
 
-	fnic_flush_tx(fnic);
+	queue_work(fnic_event_queue, &fnic->flush_work);
 
  reset_cmpl_handler_end:
 	fnic_clear_state_flags(fnic, FNIC_FLAGS_FWRESET);
@@ -736,7 +736,7 @@ static int fnic_fcpio_flogi_reg_cmpl_handler(struct fnic *fnic,
 		}
 		spin_unlock_irqrestore(&fnic->fnic_lock, flags);
 
-		fnic_flush_tx(fnic);
+		queue_work(fnic_event_queue, &fnic->flush_work);
 		queue_work(fnic_event_queue, &fnic->frame_work);
 	} else {
 		spin_unlock_irqrestore(&fnic->fnic_lock, flags);