scsi: ufs: core: Fix task management completion

The UFS driver uses blk_mq_tagset_busy_iter() when identifying task
management requests to complete, however blk_mq_tagset_busy_iter() doesn't
work.

blk_mq_tagset_busy_iter() only iterates requests dispatched by the block
layer. That appears as if it might have started since commit 37f4a24c2469
("blk-mq: centralise related handling into blk_mq_get_driver_tag") which
removed 'data->hctx->tags->rqs[rq->tag] = rq' from blk_mq_rq_ctx_init()
which gets called:

	blk_get_request
		blk_mq_alloc_request
			__blk_mq_alloc_request
				blk_mq_rq_ctx_init

Since UFS task management requests are not dispatched by the block layer,
hctx->tags->rqs[rq->tag] remains NULL, and since blk_mq_tagset_busy_iter()
relies on finding requests using hctx->tags->rqs[rq->tag], UFS task
management requests are never found by blk_mq_tagset_busy_iter().

By using blk_mq_tagset_busy_iter(), the UFS driver was relying on internal
details of the block layer, which was fragile and subsequently got
broken. Fix by removing the use of blk_mq_tagset_busy_iter() and having the
driver keep track of task management requests.

Link: https://lore.kernel.org/r/20210922091059.4040-1-adrian.hunter@intel.com
Fixes: 1235fc569e0b ("scsi: ufs: core: Fix task management request completion timeout")
Fixes: 69a6c269c097 ("scsi: ufs: Use blk_{get,put}_request() to allocate and free TMFs")
Cc: stable@vger.kernel.org
Tested-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 188de6f9105000dc69af6e48bc0a24624b5cc0ce..95be7ecdfe10b8c00d166535e2ec54bfe4c4f72e 100644 (file)
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6377,27 +6377,6 @@ static irqreturn_t ufshcd_check_errors(struct ufs_hba *hba, u32 intr_status)
        return retval;
 }
 
-struct ctm_info {
-       struct ufs_hba  *hba;
-       unsigned long   pending;
-       unsigned int    ncpl;
-};
-
-static bool ufshcd_compl_tm(struct request *req, void *priv, bool reserved)
-{
-       struct ctm_info *const ci = priv;
-       struct completion *c;
-
-       WARN_ON_ONCE(reserved);
-       if (test_bit(req->tag, &ci->pending))
-               return true;
-       ci->ncpl++;
-       c = req->end_io_data;
-       if (c)
-               complete(c);
-       return true;
-}
-
 /**
  * ufshcd_tmc_handler - handle task management function completion
  * @hba: per adapter instance
@@ -6408,18 +6387,24 @@ static bool ufshcd_compl_tm(struct request *req, void *priv, bool reserved)
  */
 static irqreturn_t ufshcd_tmc_handler(struct ufs_hba *hba)
 {
-       unsigned long flags;
-       struct request_queue *q = hba->tmf_queue;
-       struct ctm_info ci = {
-               .hba     = hba,
-       };
+       unsigned long flags, pending, issued;
+       irqreturn_t ret = IRQ_NONE;
+       int tag;
+
+       pending = ufshcd_readl(hba, REG_UTP_TASK_REQ_DOOR_BELL);
 
        spin_lock_irqsave(hba->host->host_lock, flags);
-       ci.pending = ufshcd_readl(hba, REG_UTP_TASK_REQ_DOOR_BELL);
-       blk_mq_tagset_busy_iter(q->tag_set, ufshcd_compl_tm, &ci);
+       issued = hba->outstanding_tasks & ~pending;
+       for_each_set_bit(tag, &issued, hba->nutmrs) {
+               struct request *req = hba->tmf_rqs[tag];
+               struct completion *c = req->end_io_data;
+
+               complete(c);
+               ret = IRQ_HANDLED;
+       }
        spin_unlock_irqrestore(hba->host->host_lock, flags);
 
-       return ci.ncpl ? IRQ_HANDLED : IRQ_NONE;
+       return ret;
 }
 
 /**
@@ -6542,9 +6527,9 @@ static int __ufshcd_issue_tm_cmd(struct ufs_hba *hba,
        ufshcd_hold(hba, false);
 
        spin_lock_irqsave(host->host_lock, flags);
-       blk_mq_start_request(req);
 
        task_tag = req->tag;
+       hba->tmf_rqs[req->tag] = req;
        treq->upiu_req.req_header.dword_0 |= cpu_to_be32(task_tag);
 
        memcpy(hba->utmrdl_base_addr + task_tag, treq, sizeof(*treq));
@@ -6585,6 +6570,7 @@ static int __ufshcd_issue_tm_cmd(struct ufs_hba *hba,
        }
 
        spin_lock_irqsave(hba->host->host_lock, flags);
+       hba->tmf_rqs[req->tag] = NULL;
        __clear_bit(task_tag, &hba->outstanding_tasks);
        spin_unlock_irqrestore(hba->host->host_lock, flags);
 
@@ -9635,6 +9621,12 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
                err = PTR_ERR(hba->tmf_queue);
                goto free_tmf_tag_set;
        }
+       hba->tmf_rqs = devm_kcalloc(hba->dev, hba->nutmrs,
+                                   sizeof(*hba->tmf_rqs), GFP_KERNEL);
+       if (!hba->tmf_rqs) {
+               err = -ENOMEM;
+               goto free_tmf_queue;
+       }
 
        /* Reset the attached device */
        ufshcd_device_reset(hba);

diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index f0da5d3db1fa70e7af38ad40fab4ab914a4f2506..41f6e06f91856469113e2e14f5e4639c935114df 100644 (file)
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -828,6 +828,7 @@ struct ufs_hba {
 
        struct blk_mq_tag_set tmf_tag_set;
        struct request_queue *tmf_queue;
+       struct request **tmf_rqs;
 
        struct uic_command *active_uic_cmd;
        struct mutex uic_cmd_mutex;