Re: smp dead lock of io_request_lock/queue_lock patch

From: Christoph Hellwig
Date: Sat Jan 17 2004 - 11:59:49 EST


On Sat, Jan 17, 2004 at 08:10:00AM -0500, Doug Ledford wrote:
> 4) The last issue. 2.6 already has individual host locks for drivers.
> The iorl patch for 2.4 adds the same thing. So, adding the iorl patch
> to 2.4 makes it easier to have drivers be the same between 2.4 and 2.6.
> Right now it takes some fairly convoluted #ifdef statements to get the
> locking right in a driver that supports both 2.4 and 2.6. Adding the
> iorl patch allows driver authors to basically state that they don't
> support anything prior to whatever version of 2.4 it goes into and
> remove a bunch of #ifdef crap.

Well, no. For one thing all the iorl patches miss the scsi_assign_lock
interface from 2.6 which makes drivers a big ifdef hell (especially
as the AS2.1 patch uses a different name for the lock as 3.0), and even
if it was there the use of that function is strongly discuraged in 2.6
in favour of just using the host_lock.

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