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    ncr5380: Dont release lock for PIO transfer · 1678847e
    Finn Thain 提交于
    The calls to NCR5380_transfer_pio() for DATA IN and DATA OUT phases will
    modify cmd->SCp.this_residual, cmd->SCp.ptr and cmd->SCp.buffer. That
    works as long as EH does not intervene, which became possible in
    atari_NCR5380.c when I changed the locking to bring it closer to
    NCR5380.c.
    
    If error recovery aborts the command, the scsi_cmnd in question and its
    buffer will be returned to the mid-layer. So the transfer has to cease,
    but it can't be stopped by the initiator because the target controls the
    bus phase.
    
    The problem does not arise if the lock is not released. That was fine for
    atari_scsi, because it implements DMA. For the other drivers, we have to
    release the lock and re-enable interrupts for long PIO data transfers.
    
    The solution is to split the transfer into small chunks. In between chunks
    the main loop releases the lock and re-enables interrupts. Thus interrupts
    can be serviced and eh_bus_reset_handler can intervene if need be.
    
    This fixes an oops in NCR5380_transfer_pio() that can happen when the EH
    abort handler is invoked during DATA IN or DATA OUT phase.
    
    Fixes: 11d2f63b ("ncr5380: Change instance->host_lock to hostdata->lock")
    Reported-and-tested-by: NMichael Schmitz <schmitzmic@gmail.com>
    Cc: <stable@vger.kernel.org> # 4.5
    Signed-off-by: NFinn Thain <fthain@telegraphics.com.au>
    Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
    1678847e
atari_NCR5380.c 78.9 KB