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Subject: RE: RE: [PATCH v5 05/10] scsi: ufshpb: Region inactivation in host
 mode
Reply-To: daejun7.park@samsung.com
Sender: Daejun Park <daejun7.park@samsung.com>
From:   Daejun Park <daejun7.park@samsung.com>
To:     Avri Altman <Avri.Altman@wdc.com>, Can Guo <cang@codeaurora.org>
CC:     "James E . J . Bottomley" <jejb@linux.vnet.ibm.com>,
        "Martin K . Petersen" <martin.petersen@oracle.com>,
        "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        Bart Van Assche <bvanassche@acm.org>,
        yongmyung lee <ymhungry.lee@samsung.com>,
        Daejun Park <daejun7.park@samsung.com>,
        ALIM AKHTAR <alim.akhtar@samsung.com>,
        "asutoshd@codeaurora.org" <asutoshd@codeaurora.org>,
        Zang Leigang <zangleigang@hisilicon.com>,
        Avi Shchislowski <Avi.Shchislowski@wdc.com>,
        Bean Huo <beanhuo@micron.com>,
        "stanley.chu@mediatek.com" <stanley.chu@mediatek.com>
In-Reply-To: <DM6PR04MB65751EE32D25C7E57A6BABE8FC6B9@DM6PR04MB6575.namprd04.prod.outlook.com>
Message-ID: <2038148563.21615949282962.JavaMail.epsvc@epcpadp4>
Date:   Wed, 17 Mar 2021 11:28:48 +0900
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References: <DM6PR04MB65751EE32D25C7E57A6BABE8FC6B9@DM6PR04MB6575.namprd04.prod.outlook.com>
        <20210302132503.224670-1-avri.altman@wdc.com>
        <20210302132503.224670-6-avri.altman@wdc.com>
        <25da7378d5bf4c52443ae9b47f3fd778@codeaurora.org>
        <57afb2b5d7edda61a40493d8545785b1@codeaurora.org>
        <CGME20210316083014epcas2p32d6b84e689cdbe06ee065c870b236d65@epcms2p3>
Precedence: bulk

>> >> ---
>> >>  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???
>I think your comment applies to  ufshpb_issue_umap_all_req as well,
>Which is called from slave_configure/scsi_add_lun.
> 
>Since the host-mode series is utilizing the framework laid by the device-mode,
>Maybe you can add this comment to  Daejun's last version?

Hi Avri, Can Guo

I think ufshpb_issue_umap_single_req() can be moved to end of ufshpb_evict_region().
Then we can avoid rgn_state_lock when it sends unmap command.

Thanks,
Daejun


>Thanks,
>Avri
> 
>> 
>> 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 {
> 
> 
>