lkml.org 
[lkml]   [2007]   [Jun]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: libata passthru: support PIO multi commands
> 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.

Alan
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-06-12 18:03    [from the cache]
©2003-2011 Jasper Spaans