Re: Patch added to scsi-rc-fixes-2.6: [SCSI] host lock push-down

[Jeff Garzik]

On 11/10/2010 05:40 PM, James Bottomley wrote:
> Your commit:
>
>      [SCSI] host lock push-down
>
>      Move the mid-layer's ->queuecommand() invocation from being locked
>      with the host lock to being unlocked to facilitate speeding up the
>      critical path for drivers who don't need this lock taken anyway.
>
>      The patch below presents a simple SCSI host lock push-down as an
>      equivalent transformation.  No locking or other behavior should change
>      with this patch.  All existing bugs and locking orders are preserved.
>
>      Minimal code disturbance was attempted with this change.  Most drivers
>      needed only two one-line modifications for their host lock push-down.
>
>      Signed-off-by: Jeff Garzik<jgarzik@xxxxxxxxxx>
>      Signed-off-by: James Bottomley<James.Bottomley@xxxxxxx>
>
> has been added to the upstream SCSI tree
> You can find it here:

No comments on renaming ->queuecommand to something else?

The consequences are rather dire if this goes unnoticed, yes?

	Jeff


In http://marc.info/?l=linux-ide&m=128891665713984&w=2 I wrote:
> An alternate arrangement, not presented by this patch, might
> be preferred:  in order to make it clear that queuecommand
> locking has changed, one could s/queuecommand/queuecommand_nl/ in
> Scsi_Host_Template, in order to guarantee that drivers are either
> (a) upgraded or (b) broken at compile time.  Compile-time detection of
> new locking may be desirable, and I'll volunteer to change my patch to
> do that, if community members prefer that route instead of below.

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