lkml.org 
[lkml]   [2015]   [Sep]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 3.13.y-ckt 32/57] libiscsi: Fix host busy blocking during connection teardown
    Date
    3.13.11-ckt27 -stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: John Soni Jose <sony.john@avagotech.com>

    commit 660d0831d1494a6837b2f810d08b5be092c1f31d upstream.

    In case of hw iscsi offload, an host can have N-number of active
    connections. There can be IO's running on some connections which
    make host->host_busy always TRUE. Now if logout from a connection
    is tried then the code gets into an infinite loop as host->host_busy
    is always TRUE.

    iscsi_conn_teardown(....)
    {
    .........
    /*
    * Block until all in-progress commands for this connection
    * time out or fail.
    */
    for (;;) {
    spin_lock_irqsave(session->host->host_lock, flags);
    if (!atomic_read(&session->host->host_busy)) { /* OK for ERL == 0 */
    spin_unlock_irqrestore(session->host->host_lock, flags);
    break;
    }
    spin_unlock_irqrestore(session->host->host_lock, flags);
    msleep_interruptible(500);
    iscsi_conn_printk(KERN_INFO, conn, "iscsi conn_destroy(): "
    "host_busy %d host_failed %d\n",
    atomic_read(&session->host->host_busy),
    session->host->host_failed);

    ................
    ...............
    }
    }

    This is not an issue with software-iscsi/iser as each cxn is a separate
    host.

    Fix:
    Acquiring eh_mutex in iscsi_conn_teardown() before setting
    session->state = ISCSI_STATE_TERMINATE.

    Signed-off-by: John Soni Jose <sony.john@avagotech.com>
    Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
    Reviewed-by: Chris Leech <cleech@redhat.com>
    Signed-off-by: James Bottomley <JBottomley@Odin.com>
    [ luis: backported to 3.16: adjusted context ]
    Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
    Signed-off-by: Kamal Mostafa <kamal@canonical.com>
    ---
    drivers/scsi/libiscsi.c | 25 ++-----------------------
    1 file changed, 2 insertions(+), 23 deletions(-)

    diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
    index b69b233..dbf27d6 100644
    --- a/drivers/scsi/libiscsi.c
    +++ b/drivers/scsi/libiscsi.c
    @@ -2911,10 +2911,10 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
    {
    struct iscsi_conn *conn = cls_conn->dd_data;
    struct iscsi_session *session = conn->session;
    - unsigned long flags;

    del_timer_sync(&conn->transport_timer);

    + mutex_lock(&session->eh_mutex);
    spin_lock_bh(&session->lock);
    conn->c_stage = ISCSI_CONN_CLEANUP_WAIT;
    if (session->leadconn == conn) {
    @@ -2926,28 +2926,6 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
    }
    spin_unlock_bh(&session->lock);

    - /*
    - * Block until all in-progress commands for this connection
    - * time out or fail.
    - */
    - for (;;) {
    - spin_lock_irqsave(session->host->host_lock, flags);
    - if (!session->host->host_busy) { /* OK for ERL == 0 */
    - spin_unlock_irqrestore(session->host->host_lock, flags);
    - break;
    - }
    - spin_unlock_irqrestore(session->host->host_lock, flags);
    - msleep_interruptible(500);
    - iscsi_conn_printk(KERN_INFO, conn, "iscsi conn_destroy(): "
    - "host_busy %d host_failed %d\n",
    - session->host->host_busy,
    - session->host->host_failed);
    - /*
    - * force eh_abort() to unblock
    - */
    - wake_up(&conn->ehwait);
    - }
    -
    /* flush queued up work because we free the connection below */
    iscsi_suspend_tx(conn);

    @@ -2960,6 +2938,7 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
    if (session->leadconn == conn)
    session->leadconn = NULL;
    spin_unlock_bh(&session->lock);
    + mutex_unlock(&session->eh_mutex);

    iscsi_destroy_conn(cls_conn);
    }
    --
    1.9.1


    \
     
     \ /
      Last update: 2015-09-22 21:41    [W:4.060 / U:0.032 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site