From: Albert Lee <albertcc@tw.ibm.com>
Date: Fri, 29 Apr 2005 09:34:59 +0000 (+0800)
Subject: [PATCH] libata: Prevent the interrupt handler from completing a command twice
X-Git-Tag: v2.6.12-rc5~61^2^2~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=21b1ed74ee3667dcabcba92e486988ea9119a085;p=pandora-kernel.git

[PATCH] libata: Prevent the interrupt handler from completing a command twice

Problem:
   During the libata CD-ROM stress test, sometimes the "BUG: timeout
without command" error is seen.

Root cause:
  Unexpected interrupt occurs after the ata_qc_complete() is called,
but before the SCSI error handler.  The interrupt handler is invoked
before the SCSI error handler, and it clears the command by calling
ata_qc_complete() again.  Later when the SCSI error handler is run,
the ata_queued_cmd is already gone, causing the "BUG: timeout without
command" error.

Changes:
  - Use the ATA_QCFLAG_ACTIVE flag to prevent the interrupt handler
from completing the command twice, before the scsi_error_handler.

Signed-off-by: Albert Lee <albertcc@tw.ibm.com>
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