>> In its current implementation, scsi_unblock_requests() simply
>> clears host_self_blocked in the SCSI host struct. This means
>> that either a transaction must complete or a new transaction
>
>Suppose the queue is unblocked from inside the functions called to process
>the request. In that situation the old code is correct and your code might
>introduce other problems
Re-entrancy is only prevented by holding the io-request lock or in
some cases a per-controller or per-controller driver lock.
As the comment in scsi_unblock_requests() states, this API assumes
that no locks are held. If you hold a lock in calling this routine,
you may deadlock.
>> unblocks. scsi_queue_next_request() verifies all other state
>> to ensure queuing new transactions is safe prior to proceeding.
>
>Including recursion ?
I suppose a poorly implemented use of this API could tail recurse.
The aic7xxx driver calls this routine from a timeout handler so
there is no risk of stack explosion.
>The patch seems right apart from checking these details out further.
Well, the patch was written to have minimal impact to an API that
has never been used. A more correct solution might be to queue the
affected host controller to a queue drained by a bottom-half handler.
--
Justin
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
