• Andrew Donnellan's avatar
    powerpc/eeh: eeh_pci_enable(): fix checking of post-request state · 949e9b82
    Andrew Donnellan authored
    In eeh_pci_enable(), after making the request to set the new options, we
    call eeh_ops->wait_state() to check that the request finished successfully.
    
    At the moment, if eeh_ops->wait_state() returns 0, we return 0 without
    checking that it reflects the expected outcome. This can lead to callers
    further up the chain incorrectly assuming the slot has been successfully
    unfrozen and continuing to attempt recovery.
    
    On powernv, this will occur if pnv_eeh_get_pe_state() or
    pnv_eeh_get_phb_state() return 0, which in turn occurs if the relevant OPAL
    call returns OPAL_EEH_STOPPED_MMIO_DMA_FREEZE or
    OPAL_EEH_PHB_ERROR respectively.
    
    On pseries, this will occur if pseries_eeh_get_state() returns 0, which in
    turn occurs if RTAS reports that the PE is in the MMIO Stopped and DMA
    Stopped states.
    
    Obviously, none of these cases represent a successful completion of a
    request to thaw MMIO or DMA.
    
    Fix the check so that a wait_state() return value of 0 won't be considered
    successful for the EEH_OPT_THAW_MMIO or EEH_OPT_THAW_DMA cases.
    Signed-off-by: default avatarAndrew Donnellan <andrew.donnellan@au1.ibm.com>
    Acked-by: default avatarGavin Shan <gwshan@linux.vnet.ibm.com>
    Reviewed-by: default avatarDaniel Axtens <dja@axtens.net>
    Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
    949e9b82
eeh.c 46.4 KB