lkml.org 
[lkml]   [2017]   [Jul]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v3 7/7] libsas: release disco mutex during waiting in sas_ex_discover_end_dev
    Date
    Disco mutex was introudced to prevent domain rediscovery competing
    with ata error handling(87c8331). If we have already hold the lock
    in sas_revalidate_domain and sync executing probe, deadlock caused,
    because, sas_probe_sata() also need hold disco_mutex. Since disco mutex
    use to prevent revalidata domain happen during ata error handler,
    it should be safe to release disco mutex when sync probe, because
    no new revalidate domain event would be process until the sync return,
    and the current sas revalidate domain finish.

    Signed-off-by: Yijing Wang <wangyijing@huawei.com>
    CC: John Garry <john.garry@huawei.com>
    CC: Johannes Thumshirn <jthumshirn@suse.de>
    CC: Ewan Milne <emilne@redhat.com>
    CC: Christoph Hellwig <hch@lst.de>
    CC: Tomas Henzl <thenzl@redhat.com>
    CC: Dan Williams <dan.j.williams@intel.com>
    ---
    drivers/scsi/libsas/sas_expander.c | 10 ++++++++++
    1 file changed, 10 insertions(+)

    diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
    index 9d26c28..077024e 100644
    --- a/drivers/scsi/libsas/sas_expander.c
    +++ b/drivers/scsi/libsas/sas_expander.c
    @@ -776,6 +776,7 @@ static struct domain_device *sas_ex_discover_end_dev(
    struct ex_phy *phy = &parent_ex->ex_phy[phy_id];
    struct domain_device *child = NULL;
    struct sas_rphy *rphy;
    + bool prev_lock;
    int res;

    if (phy->attached_sata_host || phy->attached_sata_ps)
    @@ -803,6 +804,7 @@ static struct domain_device *sas_ex_discover_end_dev(
    sas_ex_get_linkrate(parent, child, phy);
    sas_device_set_phy(child, phy->port);

    + prev_lock = mutex_is_locked(&child->port->ha->disco_mutex);
    #ifdef CONFIG_SCSI_SAS_ATA
    if ((phy->attached_tproto & SAS_PROTOCOL_STP) || phy->attached_sata_dev) {
    res = sas_get_ata_info(child, phy);
    @@ -832,7 +834,11 @@ static struct domain_device *sas_ex_discover_end_dev(
    SAS_ADDR(parent->sas_addr), phy_id, res);
    goto out_list_del;
    }
    + if (prev_lock)
    + mutex_unlock(&child->port->ha->disco_mutex);
    sas_disc_wait_completion(child->port, DISCE_PROBE);
    + if (prev_lock)
    + mutex_lock(&child->port->ha->disco_mutex);

    } else
    #endif
    @@ -861,7 +867,11 @@ static struct domain_device *sas_ex_discover_end_dev(
    SAS_ADDR(parent->sas_addr), phy_id, res);
    goto out_list_del;
    }
    + if (prev_lock)
    + mutex_unlock(&child->port->ha->disco_mutex);
    sas_disc_wait_completion(child->port, DISCE_PROBE);
    + if (prev_lock)
    + mutex_lock(&child->port->ha->disco_mutex);
    } else {
    SAS_DPRINTK("target proto 0x%x at %016llx:0x%x not handled\n",
    phy->attached_tproto, SAS_ADDR(parent->sas_addr),
    --
    2.5.0
    \
     
     \ /
      Last update: 2017-07-10 09:03    [W:2.389 / U:0.324 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site