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Message-ID: <a5958ce2eca11b6ddcf75fa3aeeaaa4f@codeaurora.org>
Date: Wed, 17 Mar 2021 13:34:12 +0800
From: Can Guo <cang@...eaurora.org>
To: daejun7.park@...sung.com
Cc: Avri Altman <Avri.Altman@....com>,
"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>,
ALIM AKHTAR <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 2021-03-17 13:19, Daejun Park wrote:
>>>>> >> ---
>>>>> >> 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.
>>
>> I am not the expert here, please you two fix it. I am just reporting
>> what can be wrong. Anyways, ufshpb_issue_umap_single_req() should not
>> be called with rgn_state_lock held - think about below (another
>> deadly)
>> scenario.
>>
>> lock(rgn_state_lock)
>> ufshpb_issue_umap_single_req()
>> ufshpb_prep()
>> lock(rgn_state_lock) <---------- recursive spin_lock
>>
>> BTW, @Daejun shouldn't we stop passthrough cmds from stepping
>> into ufshpb_prep()? In current code, you are trying to use below
>> check to block cmds other than write/discard/read, but a passthrough
>> cmd can not be blocked by the check.
>>
>> if (!ufshpb_is_write_or_discard_cmd(cmd) &&
>> !ufshpb_is_read_cmd(cmd) )
>> return 0;
>
> I found this problem too. I fixed it and submit next patch.
You mean in V30, which has not been uploaded yet, right?
Thanks,
Can Guo.
>
> if (blk_rq_is_scsi(cmd->request) ||
> (!ufshpb_is_write_or_discard_cmd(cmd) &&
> !ufshpb_is_read_cmd(cmd)))
> return 0;
>
>
> Thanks,
> Daejun
>
>> Thanks,
>> Can Guo.
>>
>>>
>>> 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 {
>>>>
>>>>
>>>>
>>
>>
>>
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