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

[cang]

On 2019-12-17 02:05, Greg KH wrote:
> On Mon, Dec 16, 2019 at 10:31:29PM +0800, cang@xxxxxxxxxxxxxx wrote:
> > On 2019-12-15 02:32, Bart Van Assche wrote:
> > > On 12/14/19 8:03 AM, Can Guo wrote:
> > > > In ufshcd_remove(), after SCSI host is removed, put it once so that
> > > > its
> > > > resources can be released.
> > > >
> > > > Signed-off-by: Can Guo <cang@xxxxxxxxxxxxxx>
> > > >
> > > > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> > > > index b5966fa..a86b0fd 100644
> > > > --- a/drivers/scsi/ufs/ufshcd.c
> > > > +++ b/drivers/scsi/ufs/ufshcd.c
> > > > @@ -8251,6 +8251,7 @@ void ufshcd_remove(struct ufs_hba *hba)
> > > >   	ufs_bsg_remove(hba);
> > > >   	ufs_sysfs_remove_nodes(hba->dev);
> > > >   	scsi_remove_host(hba->host);
> > > > +	scsi_host_put(hba->host);
> > > >   	/* disable interrupts */
> > > >   	ufshcd_disable_intr(hba, hba->intr_mask);
> > > >   	ufshcd_hba_stop(hba, true);
> > >
> > > Hi Can,
> > >
> > > The UFS driver may queue work asynchronously and that asynchronous
> > > work may refer to the SCSI host, e.g. ufshcd_err_handler(). Is it
> > > guaranteed that all that asynchronous work has finished before
> > > scsi_host_put() is called?
> > >
> > > Thanks,
> > >
> > > Bart.
> >
> > Hi Bart,
> >
> > As SCSI host is allocated in ufshcd_platform_init() during platform
> > drive probe, it is much more appropriate if platform driver calls
> > ufshcd_dealloc_host() in their own drv->remove() path. How do you
> > think if I change it as below? If it is OK to you, please ignore my
> > previous mails.
> >
> > diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
> > index 3d4582e..ea45756 100644
> > --- a/drivers/scsi/ufs/ufs-qcom.c
> > +++ b/drivers/scsi/ufs/ufs-qcom.c
> > @@ -3239,6 +3239,7 @@ static int ufs_qcom_remove(struct 
> > platform_device
> > *pdev)
> >
> >         pm_runtime_get_sync(&(pdev)->dev);
> >         ufshcd_remove(hba);
> > +       ufshcd_dealloc_host(hba);
> >         return 0;
> >  }
>
> Wait, why is this a platform device?  Don't you hang off of a pci
> device?  Or am I missing something earlier in this patchset?
>
> thanks,
>
> greg k-h

Hi Greg,

I am not saying someone is a platform device here. My point is
whoever allocates the SCSI host in its drv->probe(), should
de-allocate it in its own drv->remove(), just like what ufshcd-pci.c
does.

Thanks,

Can Guo.