linux-kernel - Re: [PATCH v5 05/10] scsi: ufshpb: Region inactivation in host mode

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Date:   Mon, 15 Mar 2021 15:33:26 +0800
From:   Can Guo <cang@...eaurora.org>
To:     Avri Altman <avri.altman@....com>
Cc:     "James E . J . Bottomley" <jejb@...ux.vnet.ibm.com>,
        "Martin K . Petersen" <martin.petersen@...cle.com>,
        linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org,
        gregkh@...uxfoundation.org, Bart Van Assche <bvanassche@....org>,
        yongmyung lee <ymhungry.lee@...sung.com>,
        Daejun Park <daejun7.park@...sung.com>,
        alim.akhtar@...sung.com, asutoshd@...eaurora.org,
        Zang Leigang <zangleigang@...ilicon.com>,
        Avi Shchislowski <avi.shchislowski@....com>,
        Bean Huo <beanhuo@...ron.com>, stanley.chu@...iatek.com
Subject: Re: [PATCH v5 05/10] scsi: ufshpb: Region inactivation in host mode

On 2021-03-15 12:02, Can Guo wrote:
> On 2021-03-02 21:24, Avri Altman wrote:
>> I host mode, the host is expected to send HPB-WRITE-BUFFER with
>> buffer-id = 0x1 when it inactivates a region.
>> 
>> Use the map-requests pool as there is no point in assigning a
>> designated cache for umap-requests.
>> 
>> Signed-off-by: Avri Altman <avri.altman@....com>
>> ---
>>  drivers/scsi/ufs/ufshpb.c | 14 ++++++++++++++
>>  drivers/scsi/ufs/ufshpb.h |  1 +
>>  2 files changed, 15 insertions(+)
>> 
>> diff --git a/drivers/scsi/ufs/ufshpb.c b/drivers/scsi/ufs/ufshpb.c
>> index 6f4fd22eaf2f..0744feb4d484 100644
>> --- a/drivers/scsi/ufs/ufshpb.c
>> +++ b/drivers/scsi/ufs/ufshpb.c
>> @@ -907,6 +907,7 @@ static int ufshpb_execute_umap_req(struct 
>> ufshpb_lu *hpb,
>> 
>>  	blk_execute_rq_nowait(q, NULL, req, 1, ufshpb_umap_req_compl_fn);
>> 
>> +	hpb->stats.umap_req_cnt++;
>>  	return 0;
>>  }
>> 
>> @@ -1103,6 +1104,12 @@ static int ufshpb_issue_umap_req(struct 
>> ufshpb_lu *hpb,
>>  	return -EAGAIN;
>>  }
>> 
>> +static int ufshpb_issue_umap_single_req(struct ufshpb_lu *hpb,
>> +					struct ufshpb_region *rgn)
>> +{
>> +	return ufshpb_issue_umap_req(hpb, rgn);
>> +}
>> +
>>  static int ufshpb_issue_umap_all_req(struct ufshpb_lu *hpb)
>>  {
>>  	return ufshpb_issue_umap_req(hpb, NULL);
>> @@ -1115,6 +1122,10 @@ static void __ufshpb_evict_region(struct 
>> ufshpb_lu *hpb,
>>  	struct ufshpb_subregion *srgn;
>>  	int srgn_idx;
>> 
>> +
>> +	if (hpb->is_hcm && ufshpb_issue_umap_single_req(hpb, rgn))
> 
> __ufshpb_evict_region() is called with rgn_state_lock held and IRQ 
> disabled,
> when ufshpb_issue_umap_single_req() invokes blk_execute_rq_nowait(), 
> below
> warning shall pop up every time, fix it?
> 
> void blk_execute_rq_nowait(struct request_queue *q, struct gendisk 
> *bd_disk,
> 		   struct request *rq, int at_head,
> 			   rq_end_io_fn *done)
> {
> 	WARN_ON(irqs_disabled());
> ...
> 

Moreover, since we are here with rgn_state_lock held and IRQ disabled,
in ufshpb_get_req(), rq = kmem_cache_alloc(hpb->map_req_cache, 
GFP_KERNEL)
has the GFP_KERNEL flag, scheduling while atomic???

Can Guo.

> Thanks.
> Can Guo.
> 
>> +		return;
>> +
>>  	lru_info = &hpb->lru_info;
>> 
>>  	dev_dbg(&hpb->sdev_ufs_lu->sdev_dev, "evict region %d\n", 
>> rgn->rgn_idx);
>> @@ -1855,6 +1866,7 @@ ufshpb_sysfs_attr_show_func(rb_noti_cnt);
>>  ufshpb_sysfs_attr_show_func(rb_active_cnt);
>>  ufshpb_sysfs_attr_show_func(rb_inactive_cnt);
>>  ufshpb_sysfs_attr_show_func(map_req_cnt);
>> +ufshpb_sysfs_attr_show_func(umap_req_cnt);
>> 
>>  static struct attribute *hpb_dev_stat_attrs[] = {
>>  	&dev_attr_hit_cnt.attr,
>> @@ -1863,6 +1875,7 @@ static struct attribute *hpb_dev_stat_attrs[] = 
>> {
>>  	&dev_attr_rb_active_cnt.attr,
>>  	&dev_attr_rb_inactive_cnt.attr,
>>  	&dev_attr_map_req_cnt.attr,
>> +	&dev_attr_umap_req_cnt.attr,
>>  	NULL,
>>  };
>> 
>> @@ -1978,6 +1991,7 @@ static void ufshpb_stat_init(struct ufshpb_lu 
>> *hpb)
>>  	hpb->stats.rb_active_cnt = 0;
>>  	hpb->stats.rb_inactive_cnt = 0;
>>  	hpb->stats.map_req_cnt = 0;
>> +	hpb->stats.umap_req_cnt = 0;
>>  }
>> 
>>  static void ufshpb_param_init(struct ufshpb_lu *hpb)
>> diff --git a/drivers/scsi/ufs/ufshpb.h b/drivers/scsi/ufs/ufshpb.h
>> index bd4308010466..84598a317897 100644
>> --- a/drivers/scsi/ufs/ufshpb.h
>> +++ b/drivers/scsi/ufs/ufshpb.h
>> @@ -186,6 +186,7 @@ struct ufshpb_stats {
>>  	u64 rb_inactive_cnt;
>>  	u64 map_req_cnt;
>>  	u64 pre_req_cnt;
>> +	u64 umap_req_cnt;
>>  };
>> 
>>  struct ufshpb_lu {