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From:   Avri Altman <Avri.Altman@wdc.com>
To:     "cang@codeaurora.org" <cang@codeaurora.org>
CC:     "asutoshd@codeaurora.org" <asutoshd@codeaurora.org>,
        "nguyenb@codeaurora.org" <nguyenb@codeaurora.org>,
        "rnayak@codeaurora.org" <rnayak@codeaurora.org>,
        "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
        "kernel-team@android.com" <kernel-team@android.com>,
        "saravanak@google.com" <saravanak@google.com>,
        "salyzyn@google.com" <salyzyn@google.com>,
        Alim Akhtar <alim.akhtar@samsung.com>,
        Pedro Sousa <pedrom.sousa@synopsys.com>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Stanley Chu <stanley.chu@mediatek.com>,
        Bean Huo <beanhuo@micron.com>,
        Venkat Gopalakrishnan <venkatg@codeaurora.org>,
        Tomas Winkler <tomas.winkler@intel.com>,
        open list <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v2 1/3] scsi: ufs: Put SCSI host after remove it
Thread-Topic: [PATCH v2 1/3] scsi: ufs: Put SCSI host after remove it
Thread-Index: AQHVr//RJYxYdS3dXUmhxTnGX2MLCqe0vdGQgAAIXgCAAANkQA==
Date:   Wed, 11 Dec 2019 11:22:16 +0000
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>=20
>=20
> On 2019-12-11 18:37, Avri Altman 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@codeaurora.org>
> >
> > This is not really part of this patchset, is it?
> >
>=20
> Hi Avri,
>=20
> I put this change in the same patchset due to #1. The main patch has
> dependency on it #2. Consider a scenario where platform driver is also co=
mpiled
> as a module, say ufs_qcom.ko.
>      In this case, we have two modules, ufs-qcom.ko and ufs-bsg.ko. If do=
 insmod
> ufs-qcom.ko
>      then rmmod ufs-qcom.ko and do insmod ufs-qcom.ko again, without this
> change, because scsi
>      host was not release, the new scsi host will have a different host n=
umber,
> meaning
>      hba->host->host_no will be 1, but not 0. Now if do insmod ufs-bsg.ko=
 now,
> the ufs-bsg dev
>      created in /dev/bsg/ will be ufs-bsg1, but not ufs-bsg0. If keep try=
ing these
> operations,
>      the ufs-bsg device's name will be messed up. This change make sure a=
fter ufs-
> qcom.ko is removed
>      and installed back, its hba->host->host_no stays 0, so that ufs-bsg =
device
> name stays same.
Looks like we needed to manage the ufs-bsg nodes using an IDA, instead of h=
ost_no?


>=20
> Thanks,
>=20
> Can Guo.
>=20
> >> ---
> >>  drivers/scsi/ufs/ufshcd.c | 1 +
> >>  1 file changed, 1 insertion(+)
> >>
> >> 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);
> >> --
> >> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
> >> Forum, a Linux Foundation Collaborative Project