Much better... Just updated #upstream-fixes with the below patch.
James just posted to linux-scsi
[PATCH] Eliminate error handler overload of the SCSI serial number
but as Tejun pointed out, we _completely and entirely_ replace the SCSI
error handler apparatus with our own, thereby eliminating any
possibility that we would ever read or use cmd->serial_number.
Our lock profile is quite a bit improved.
Further simplifications and cleanups related to 'done' are possible,
but those are kept separate from the change below.
commit 23e701e6208191ad103517ae7a700f2dc59ab2ec
Author: Jeff Garzik <jeff@xxxxxxxxxx>
Date: Wed Nov 17 12:03:58 2010 -0500
[libata] remove SCSI host lock and serial number usage from ata_scsi_queuecmd
cmd->serial_number is never tested in any path we reach; therefore we may
remove the call to scsi_cmd_get_serial() inside DEF_SCSI_QCMD, the SCSI
host_lock acquisition surrounding it, and our own SCSI host_lock
unlock+relock cycle.
Signed-off-by: Jeff Garzik <jgarzik@xxxxxxxxxx>
drivers/ata/libata-scsi.c | 21 +++++++++------------
1 file changed, 9 insertions(+), 12 deletions(-)
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 19835d3..66aa4be 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3166,8 +3166,8 @@ static inline int __ata_scsi_queuecmd(struct scsi_cmnd *scmd,
/**
* ata_scsi_queuecmd - Issue SCSI cdb to libata-managed device
+ * @shost: SCSI host of command to be sent
* @cmd: SCSI command to be sent
- * @done: Completion function, called when command is complete
*
* In some cases, this function translates SCSI commands into
* ATA taskfiles, and queues the taskfiles to be sent to
@@ -3177,42 +3177,39 @@ static inline int __ata_scsi_queuecmd(struct scsi_cmnd *scmd,
* ATA and ATAPI devices appearing as SCSI devices.
*
* LOCKING:
- * Releases scsi-layer-held lock, and obtains host lock.
+ * ATA host lock
*
* RETURNS:
* Return value from __ata_scsi_queuecmd() if @cmd can be queued,
* 0 otherwise.
*/
-static int ata_scsi_queuecmd_lck(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
+int ata_scsi_queuecmd(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
{
struct ata_port *ap;
struct ata_device *dev;
struct scsi_device *scsidev = cmd->device;
- struct Scsi_Host *shost = scsidev->host;
int rc = 0;
+ unsigned long irq_flags;
ap = ata_shost_to_port(shost);
- spin_unlock(shost->host_lock);
- spin_lock(ap->lock);
+ spin_lock_irqsave(ap->lock, irq_flags);
ata_scsi_dump_cdb(ap, cmd);
dev = ata_scsi_find_dev(ap, scsidev);
if (likely(dev))
- rc = __ata_scsi_queuecmd(cmd, done, dev);
+ rc = __ata_scsi_queuecmd(cmd, cmd->scsi_done, dev);
else {
cmd->result = (DID_BAD_TARGET << 16);
- done(cmd);
+ cmd->scsi_done(cmd);
}
- spin_unlock(ap->lock);
- spin_lock(shost->host_lock);
+ spin_unlock_irqrestore(ap->lock, irq_flags);
+
return rc;
}
-DEF_SCSI_QCMD(ata_scsi_queuecmd)
-
/**
* ata_scsi_simulate - simulate SCSI command on ATA device
* @dev: the target device
--
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