Re: [PATCH v3 10/17] scsi: ufs: Fix a deadlock in the error handler

[Bart Van Assche <bvanassche@acm.org>]

On 12/1/21 5:48 AM, Adrian Hunter wrote:
> I think cmd_queue is not used anymore after this.

Let's remove cmd_queue via a separate patch. I have started testing this patch:

Subject: [PATCH] scsi: ufs: Remove hba->cmd_queue

Suggested-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
  drivers/scsi/ufs/ufshcd.c | 11 +----------
  drivers/scsi/ufs/ufshcd.h |  2 --
  2 files changed, 1 insertion(+), 12 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 5b3efc880246..d379c2b0c058 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -9409,7 +9409,6 @@ void ufshcd_remove(struct ufs_hba *hba)
  	ufs_sysfs_remove_nodes(hba->dev);
  	blk_cleanup_queue(hba->tmf_queue);
  	blk_mq_free_tag_set(&hba->tmf_tag_set);
-	blk_cleanup_queue(hba->cmd_queue);
  	scsi_remove_host(hba->host);
  	/* disable interrupts */
  	ufshcd_disable_intr(hba, hba->intr_mask);
@@ -9630,12 +9629,6 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
  		goto out_disable;
  	}

-	hba->cmd_queue = blk_mq_init_queue(&hba->host->tag_set);
-	if (IS_ERR(hba->cmd_queue)) {
-		err = PTR_ERR(hba->cmd_queue);
-		goto out_remove_scsi_host;
-	}
-
  	hba->tmf_tag_set = (struct blk_mq_tag_set) {
  		.nr_hw_queues	= 1,
  		.queue_depth	= hba->nutmrs,
@@ -9644,7 +9637,7 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
  	};
  	err = blk_mq_alloc_tag_set(&hba->tmf_tag_set);
  	if (err < 0)
-		goto free_cmd_queue;
+		goto out_remove_scsi_host;
  	hba->tmf_queue = blk_mq_init_queue(&hba->tmf_tag_set);
  	if (IS_ERR(hba->tmf_queue)) {
  		err = PTR_ERR(hba->tmf_queue);
@@ -9713,8 +9706,6 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
  	blk_cleanup_queue(hba->tmf_queue);
  free_tmf_tag_set:
  	blk_mq_free_tag_set(&hba->tmf_tag_set);
-free_cmd_queue:
-	blk_cleanup_queue(hba->cmd_queue);
  out_remove_scsi_host:
  	scsi_remove_host(hba->host);
  out_disable:
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 411c6015bbfe..88c20f3608c2 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -738,7 +738,6 @@ struct ufs_hba_monitor {
   * @host: Scsi_Host instance of the driver
   * @dev: device handle
   * @lrb: local reference block
- * @cmd_queue: Used to allocate command tags from hba->host->tag_set.
   * @outstanding_tasks: Bits representing outstanding task requests
   * @outstanding_lock: Protects @outstanding_reqs.
   * @outstanding_reqs: Bits representing outstanding transfer requests
@@ -805,7 +804,6 @@ struct ufs_hba {

  	struct Scsi_Host *host;
  	struct device *dev;
-	struct request_queue *cmd_queue;
  	/*
  	 * This field is to keep a reference to "scsi_device" corresponding to
  	 * "UFS device" W-LU.