scsi: srp_transport: Move queuecommand() wait code to SCSI core

[android-x86/kernel.git] / drivers / scsi / scsi_lib.c

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index f23ec24..0f81add 100644 (file)
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2734,6 +2734,39 @@ void sdev_evt_send_simple(struct scsi_device *sdev,
 EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
 
 /**
+ * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn()
+ * @sdev: SCSI device to count the number of scsi_request_fn() callers for.
+ */
+static int scsi_request_fn_active(struct scsi_device *sdev)
+{
+       struct request_queue *q = sdev->request_queue;
+       int request_fn_active;
+
+       WARN_ON_ONCE(sdev->host->use_blk_mq);
+
+       spin_lock_irq(q->queue_lock);
+       request_fn_active = q->request_fn_active;
+       spin_unlock_irq(q->queue_lock);
+
+       return request_fn_active;
+}
+
+/**
+ * scsi_wait_for_queuecommand() - wait for ongoing queuecommand() calls
+ * @sdev: SCSI device pointer.
+ *
+ * Wait until the ongoing shost->hostt->queuecommand() calls that are
+ * invoked from scsi_request_fn() have finished.
+ */
+static void scsi_wait_for_queuecommand(struct scsi_device *sdev)
+{
+       WARN_ON_ONCE(sdev->host->use_blk_mq);
+
+       while (scsi_request_fn_active(sdev))
+               msleep(20);
+}
+
+/**
  *     scsi_device_quiesce - Block user issued commands.
  *     @sdev:  scsi device to quiesce.
  *
@@ -2817,8 +2850,7 @@ EXPORT_SYMBOL(scsi_target_resume);
  * @sdev:      device to block
  *
  * Block request made by scsi lld's to temporarily stop all
- * scsi commands on the specified device.  Called from interrupt
- * or normal process context.
+ * scsi commands on the specified device. May sleep.
  *
  * Returns zero if successful or error if not
  *
@@ -2827,6 +2859,10 @@ EXPORT_SYMBOL(scsi_target_resume);
  *     (which must be a legal transition).  When the device is in this
  *     state, all commands are deferred until the scsi lld reenables
  *     the device with scsi_device_unblock or device_block_tmo fires.
+ *
+ * To do: avoid that scsi_send_eh_cmnd() calls queuecommand() after
+ * scsi_internal_device_block() has blocked a SCSI device and also
+ * remove the rport mutex lock and unlock calls from srp_queuecommand().
  */
 int
 scsi_internal_device_block(struct scsi_device *sdev)
@@ -2854,6 +2890,7 @@ scsi_internal_device_block(struct scsi_device *sdev)
                spin_lock_irqsave(q->queue_lock, flags);
                blk_stop_queue(q);
                spin_unlock_irqrestore(q->queue_lock, flags);
+               scsi_wait_for_queuecommand(sdev);
        }
 
        return 0;