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scsi: ufs: core: Fix task management completion

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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 37f4a24c24
("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: 1235fc569e ("scsi: ufs: core: Fix task management request completion timeout")
Fixes: 69a6c269c0 ("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>
This commit is contained in:
Adrian Hunter 2021-09-22 12:10:59 +03:00 committed by Martin K. Petersen
parent c5336400ca
commit f5ef336fd2
2 changed files with 23 additions and 30 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

52
drivers/scsi/ufs/ufshcd.c
View file

@ -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);

1
drivers/scsi/ufs/ufshcd.h
View file

@ -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;