linux-kernel - Re: [PATCH 1/2] scsi: ufs: Put SCSI host after remove it

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Date:   Mon, 16 Dec 2019 09:34:27 +0800
From:   cang@...eaurora.org
To:     Bart Van Assche <bvanassche@....org>
Cc:     asutoshd@...eaurora.org, nguyenb@...eaurora.org,
        rnayak@...eaurora.org, linux-scsi@...r.kernel.org,
        kernel-team@...roid.com, saravanak@...gle.com, salyzyn@...gle.com,
        Alim Akhtar <alim.akhtar@...sung.com>,
        Avri Altman <avri.altman@....com>,
        Pedro Sousa <pedrom.sousa@...opsys.com>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        Stanley Chu <stanley.chu@...iatek.com>,
        Bean Huo <beanhuo@...ron.com>,
        Venkat Gopalakrishnan <venkatg@...eaurora.org>,
        Tomas Winkler <tomas.winkler@...el.com>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] scsi: ufs: Put SCSI host after remove it

On 2019-12-16 05:55, Bart Van Assche wrote:
> On 2019-12-14 14:24, cang@...eaurora.org wrote:
>> How do you think if I replace my patch with below one?
>> In this way, you can also move blk_cleanup_queue() behind
>> cancel_work_sync(eh_work).
>> 
>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>> index b5966fa..bd4ae75 100644
>> --- a/drivers/scsi/ufs/ufshcd.c
>> +++ b/drivers/scsi/ufs/ufshcd.c
>> @@ -8251,15 +8251,17 @@ void ufshcd_remove(struct ufs_hba *hba)
>>         ufs_bsg_remove(hba);
>>         ufs_sysfs_remove_nodes(hba->dev);
>>         scsi_remove_host(hba->host);
>> -       /* disable interrupts */
>> -       ufshcd_disable_intr(hba, hba->intr_mask);
>> -       ufshcd_hba_stop(hba, true);
>> -
>>         ufshcd_exit_clk_scaling(hba);
>>         ufshcd_exit_clk_gating(hba);
>>         if (ufshcd_is_clkscaling_supported(hba))
>>                 device_remove_file(hba->dev,
>> &hba->clk_scaling.enable_attr);
>> +       cancel_work_sync(&hba->eeh_work);
>> +       cancel_work_sync(&hba->eh_work);
>> +       /* disable interrupts */
>> +       ufshcd_disable_intr(hba, hba->intr_mask);
>> +       ufshcd_hba_stop(hba, true);
>>         ufshcd_hba_exit(hba);
>> +       ufshcd_dealloc_host(hba);
>>  }
>>  EXPORT_SYMBOL_GPL(ufshcd_remove);
> 
> Hi Can,
> 
> To which kernel tree does the above patch apply? I'm asking this 
> because
> I don't see the recently added blk_cleanup_queue() calls in the above
> patch. Please start from Martin's latest scsi-queue branch when
> preparing SCSI patches.
> 
> Additionally, is it on purpose that there is no scsi_host_put() call in
> the above code? I'd like to keep that call because without that call a
> memory leak will occur when unloading the ufshcd-core kernel driver.
> 
> Thanks,
> 
> Bart.


Hi Bart,

This is applied to 5.5/scsi-queue. The two changes I patsed from you are
not merged yet, I am still doing code review to them, so there is no
blk_cleanup_queue() calls in my code base. I am just saying you may move
your blk_cleanup_queue() calls below cancel_work_sync(&hba->eh_work) if
my change applies. How do you think?

scsi_host_put() was there before but explicitly removed by
afa3dfd42d205b106787476647735aa1de1a5d02. I agree with you, without this
change, there is memory leak.

Thanks,

Can Guo.