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    Subject[PATCH 5.10 144/154] scsi: ufs: core: Fix task management completion
    Date
    From: Adrian Hunter <adrian.hunter@intel.com>

    commit f5ef336fd2e4c36dedae4e7ca66cf5349d6fda62 upstream.

    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>
    [Adrian: Backport to v5.10]
    Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    drivers/scsi/ufs/ufshcd.c | 52 ++++++++++++++++++++--------------------------
    drivers/scsi/ufs/ufshcd.h | 1
    2 files changed, 24 insertions(+), 29 deletions(-)

    --- a/drivers/scsi/ufs/ufshcd.c
    +++ b/drivers/scsi/ufs/ufshcd.c
    @@ -6099,27 +6099,6 @@ static irqreturn_t ufshcd_check_errors(s
    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
    @@ -6130,14 +6109,22 @@ static bool ufshcd_compl_tm(struct reque
    */
    static irqreturn_t ufshcd_tmc_handler(struct ufs_hba *hba)
    {
    - struct request_queue *q = hba->tmf_queue;
    - struct ctm_info ci = {
    - .hba = hba,
    - .pending = ufshcd_readl(hba, REG_UTP_TASK_REQ_DOOR_BELL),
    - };
    + unsigned long pending, issued;
    + irqreturn_t ret = IRQ_NONE;
    + int tag;
    +
    + pending = ufshcd_readl(hba, REG_UTP_TASK_REQ_DOOR_BELL);
    +
    + 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;

    - blk_mq_tagset_busy_iter(q->tag_set, ufshcd_compl_tm, &ci);
    - return ci.ncpl ? IRQ_HANDLED : IRQ_NONE;
    + complete(c);
    + ret = IRQ_HANDLED;
    + }
    +
    + return ret;
    }

    /**
    @@ -6267,9 +6254,9 @@ static int __ufshcd_issue_tm_cmd(struct
    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->req_header.dword_0 |= cpu_to_be32(task_tag);

    memcpy(hba->utmrdl_base_addr + task_tag, treq, sizeof(*treq));
    @@ -6313,6 +6300,7 @@ static int __ufshcd_issue_tm_cmd(struct
    }

    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);

    @@ -9235,6 +9223,12 @@ int ufshcd_init(struct ufs_hba *hba, voi
    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_vops_device_reset(hba);
    --- a/drivers/scsi/ufs/ufshcd.h
    +++ b/drivers/scsi/ufs/ufshcd.h
    @@ -734,6 +734,7 @@ 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;

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