Hello.

On 09/06/2011 08:58 PM, Tejun Heo wrote:

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ata_sff_data_xfer[32]() use pad area if the transfer size isn't
multiple of transfer size; however, this area wasn't cleared and
garbage data in pad area could be transferred to the device.  Make
sure the pad area is cleared.

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Signed-off-by: Tejun Heo<tj@kernel.org>
Cc: Lei Ming<tom.leiming@gmail.com>

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    And what's the problem with garbage data? Why it's worse than 0s?

There were devices which puke on random garbage at the end of CDB and

    Note that ATAPI CDBs are always aligned to 4 bytes, so this path should 
never be hit when sending them.

in general sending indeterministic garbage to external device is a bad
idea.  It increases chance of problems which can be difficult to
reproduce and track down while gaining nothing.

    Problems with "don't care" padding bytes? Dunno...

It really is a stupid thing to do.

    Well, at least the old code was equally stupid before I patched it. :-)

Thanks.

WBR, Sergei