Messages in this thread | | | Date | Tue, 12 Jun 2007 17:05:19 +0100 | From | Alan Cox <> | Subject | Re: libata passthru: support PIO multi commands |
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> ata_scsi_pass_thru() is not executed at ioctl submission time (block > queue submission time), but rather immediately before it is issued to > the drive. At that point you know the bus is idle, all other commands > have finished executing, and dev->multi_count is fresh not stale. The > code path goes from ata_scsi_pass_thru() to ata_qc_issue() without > releasing the spinlock, even.
Think up to user space
Poorusersapp set multicount to 4
Evilproprietarytuningdaemon set multicount to 8
Poorusersapp issue I/O
at which point an error is indeed best.
> But the last point is true -- we should error rather than just warn > there, AFAICS.
Definitely. We've been asked "please do something stupid" and not even in a case where the requester may know better.
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