• Bodo Stroesser's avatar
    scsi: target: Put lun_ref at end of tmr processing · f2e6b75f
    Bodo Stroesser authored
    Testing with Loopback I found that, after a Loopback LUN has executed a
    TMR, I can no longer unlink the LUN.  The rm command hangs in
    transport_clear_lun_ref() at wait_for_completion(&lun->lun_shutdown_comp)
    The reason is, that transport_lun_remove_cmd() is not called at the end of
    target_tmr_work().
    
    It seems, that in other fabrics this call happens implicitly when the
    fabric drivers call transport_generic_free_cmd() during their
    ->queue_tm_rsp().
    
    Unfortunately Loopback seems to not comply to the common way
    of calling transport_generic_free_cmd() from ->queue_*().
    Instead it calls transport_generic_free_cmd() from its
      ->check_stop_free() only.
    
    But the ->check_stop_free() is called by
    transport_cmd_check_stop_to_fabric() after it has reset the se_cmd->se_lun
    pointer.  Therefore the following transport_generic_free_cmd() skips the
    transport_lun_remove_cmd().
    
    So this patch re-adds the transport_lun_remove_cmd() at the end of
    target_tmr_work(), which was removed during commit 2c9fa49e ("scsi:
    target/core: Make ABORT and LUN RESET handling synchronous").
    
    For fabrics using transport_generic_free_cmd() in the usual way the double
    call to transport_lun_remove_cmd() doesn't harm, as
    transport_lun_remove_cmd() checks for this situation and does not release
    lun_ref twice.
    
    Link: https://lore.kernel.org/r/20200513153443.3554-1-bstroesser@ts.fujitsu.com
    Fixes: 2c9fa49e ("scsi: target/core: Make ABORT and LUN RESET handling synchronous")
    Cc: stable@vger.kernel.org
    Tested-by: default avatarBryant G. Ly <bryangly@gmail.com>
    Reviewed-by: default avatarBart van Assche <bvanassche@acm.org>
    Signed-off-by: default avatarBodo Stroesser <bstroesser@ts.fujitsu.com>
    Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
    f2e6b75f
target_core_transport.c 92.8 KB