• Finn Thain's avatar
    ncr5380: Remove disused atari_NCR5380.c core driver · c4ec6f92
    Finn Thain authored
    Now that atari_scsi and sun3_scsi have been converted to use the NCR5380.c
    core driver, remove atari_NCR5380.c. Also remove the last vestiges of its
    Tagged Command Queueing implementation from the wrapper drivers.
    
    The TCQ support in atari_NCR5380.c is abandoned by this patch. It is not
    merged into the remaining core driver because,
    
    1) atari_scsi defines SUPPORT_TAGS but leaves FLAG_TAGGED_QUEUING disabled
    by default, which indicates that it is mostly undesirable.
    
    2) I'm told that it doesn't work correctly when enabled.
    
    3) The algorithm does not make use of block layer tags which it will have
    to do because scmd->tag is deprecated.
    
    4) sun3_scsi doesn't define SUPPORT_TAGS at all, yet the the SUPPORT_TAGS
    macro interacts with the CONFIG_SUN3 macro in 'interesting' ways.
    
    5) Compile-time configuration with macros like SUPPORT_TAGS caused the
    configuration space to explode, leading to untestable and unmaintainable
    code that is too hard to reason about.
    
    The merge_contiguous_buffers() code is also abandoned. This was unused
    by sun3_scsi. Only atari_scsi used it and then only on TT, because only TT
    supports scatter/gather. I suspect that the TT would work fine with
    ENABLE_CLUSTERING instead. If someone can benchmark the difference then
    perhaps the merge_contiguous_buffers() code can be be justified. Until
    then we are better off without the extra complexity.
    Signed-off-by: default avatarFinn Thain <fthain@telegraphics.com.au>
    Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
    Tested-by: default avatarMichael Schmitz <schmitzmic@gmail.com>
    Tested-by: default avatarOndrej Zary <linux@rainbow-software.org>
    Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
    c4ec6f92