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[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>
This commit is contained in:
Albert Lee 2005-04-29 17:34:59 +08:00 committed by Jeff Garzik
parent f85bdb9ce9
commit 21b1ed74ee
1 changed files with 4 additions and 2 deletions
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6
drivers/scsi/libata-core.c
View File

@ -2539,7 +2539,7 @@ static void atapi_request_sense(struct ata_port *ap, struct ata_device *dev,
ata_sg_init_one(qc, cmd->sense_buffer, sizeof(cmd->sense_buffer));
qc->dma_dir = DMA_FROM_DEVICE;
memset(&qc->cdb, 0, sizeof(ap->cdb_len));
memset(&qc->cdb, 0, ap->cdb_len);
qc->cdb[0] = REQUEST_SENSE;
qc->cdb[4] = SCSI_SENSE_BUFFERSIZE;
@ -2811,6 +2811,7 @@ void ata_qc_complete(struct ata_queued_cmd *qc, u8 drv_stat)
/* call completion callback */
rc = qc->complete_fn(qc, drv_stat);
qc->flags &= ~ATA_QCFLAG_ACTIVE;
/* if callback indicates not to complete command (non-zero),
* return immediately
@ -3229,7 +3230,8 @@ irqreturn_t ata_interrupt (int irq, void *dev_instance, struct pt_regs *regs)
struct ata_queued_cmd *qc;
qc = ata_qc_from_tag(ap, ap->active_tag);
if (qc && (!(qc->tf.ctl & ATA_NIEN)))
if (qc && (!(qc->tf.ctl & ATA_NIEN)) &&
(qc->flags & ATA_QCFLAG_ACTIVE))
handled |= ata_host_intr(ap, qc);
}
}